A Disappearing Pyrex Rod

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A Disappearing Pyrex Rod Powered By Docstoc

      Presenter: John Munro
        Highroad Academy

      Professional Development
    Password: “teachersonly123”
             Why Teachers Avoid Experiments
Preparation – setting up a lab takes too long

Materials – the equipment is not available

Failure – it might not go as planned

Risk – some activities are too dangerous

Cost – it is too expensive to supply the class with the

Content – I have too much material to cover

Knowledge – I do not have enough background in science
        Why We Should Use Experiments:

    Because getting into it is the whole point of

   The application of the scientific method is the
    means by which the content of science is

                       And …

It’s a lot more exciting that way.
Scientific processes engage the learner and
require active learning…..
          CONTENT                        Curriculum
 Reaction type (combustion)               10-C4
 reaction rate
Concepts: chemical change, combustion, reactants and products
Materials: Large water cooler bottle; 30 mL of isopropyl alcohol; 1 m long stick with
wooden splint attached; safety goggles; fire safety blanket (highly recommended); safety
shield (highly recommended)
-do not use methanol it is far too volatile
-do not perform in a high oxygen environment
-perform in well ventilated area
-recap bottle of alcohol and remove from demonstration area before igniting alcohol
-wear protective eyewear; a shield is highly recommended
-do not use a glass bottle; use only a plastic bottle
PROCEDURE: (read carefully)
-pour 20-30 mL of isopropyl alcohol into a large water cooler bottle
-swirl contents to ensure that all interior surfaces are covered
-pour off excess alcohol to avoid afterburning
-ensure 4 feet min of overhead height
-wear goggles and use a protective Plexiglas shield
-ignite from a distance with a wooden splint attached to a pole
-keep your distance
-after flame goes out you can pour off the water to show the formed products of
combustion this is a one-time demo since the O2 in the bottle is depleted by the combustion
and CO2 has built up; you can show that a second attempt will not ignite by repeating the
experiment but I usually don’t want to waste the propanol
-demonstrate the products of combustion by pouring off the water produced in the
reaction. The bottle is filled with CO2
-may be repeated with diluted isopropyl alcohol (try rubbing alcohol). It will be much less
exciting and can be related to reaction rate and concentration.
              CONTENT                    Curriculum Link
 Bohr’s theory of the atom                    9-C2
Introduction: a twist on the same of spectrum of metals test which investigates chemical
property in relation to alkali metals and Bohr models
Materials: borosilicate Petri dishes; ceramic tiles; methyl alcohol; copper (II) chloride;
     lithium chloride; potassium chloride; strontium chloride; sodium chloride; lighter or

-methyl alcohol is extremely flammable
-remove capped container from demonstration area
-use only borosilicate Petri dishes
-never add methyl alcohol to hot dishes
-do not repeat demo until cooled
-use flame proof surface
-keep dishes separated to avoid jumping flames
-keep cover nearby for extinguishing flame
-wear goggles

     1. place Petri dishes in row on ceramic tiles
     2. add ~5g of each different solid salt to a separate dish
     3. add ~15 mL of methyl alcohol
     4. turn down lights and observe---extinguish flames with lid
     6. color will intensify as alcohol burns off
Try with barium chloride, calcium chloride, and rubidium chloride

               CONTENT                    Curriculum Link
 reaction rate/catalysts                      10-C4-5
 reaction type (decomposition)
Observe the effect of a catalyst on the reaction rate for the decomposition of hydrogen
Safety Considerations:
30% Hydrogen peroxide is a strong oxidizing agent and is extremely corrosive to skin, eyes
and respiratory tract
It is also a dangerous fire and explosion risk. DO NOT heat this material
Do not ingest any of the reactants used in this demonstration
Do not stand over the demonstration as steam is produced
Wear safety goggles and gloves
Place 20 mL of 30% H2O2 in a large graduated cylinder
Add a scoop of Alconox detergent to the cylinder
Place the graduated cylinder in a plastic demonstration tray
Quickly pour 5mL of 2M sodium iodide into the graduated cylinder
Can be repeated with less concentrated solutions of hydrogen peroxide
PHANTOM FUEL (not shown during workshop)
               CONTENT                    Curriculum Link
 Kinetic molecular theory                      8-C6
 Viscosity of a fluid
Observe the ignition of hexane vapour as an indication of fluid flow, density and chemical
Safety Considerations: take precautions to avoid open flame. Do not keep open bottle of
hexane near open flame. Keep clothing and hair clear of flame. Take care to avoid igniting
hexane in plastic bottle.
Place 5-10 mL of hexane in a 2 L plastic bottle. Cap the bottle and leave it to stand several
minutes in order to permit vapour to form. Set angled channel in a slightly elevated
position tilted toward a small lit candle. Remove cap from bottle and slowly and carefully
pour the vapour in the bottle into the channel. Hexane vapour will ignite upon reaching the
candle. Perform in a darkened room for greater effect.

Goldenrod Paper
             CONTENT                    Curriculum Link
 Acid/base properties                    Gr 10 chem

This goldenrod paper is colored with a dye which is an acid-base indicator. It turns bright
red in bases (eg. solutions of ammonia, baking soda or washing soda) and golden-yellow in
acids (eg. vinegar or lemon juice). Try the following:
1. With a Q-Tip, write a message with household ammonia. As the ammonia evaporates, the
red message will disappear.
2. Write a permanent message with a base such as a solution of baking or washing soda. The
message remains.
3. Write an invisible message on the goldenrod paper using a piece of candle wax. Spray the
paper with a basic solution to see the message.
4. Use goldenrod paper to classify safe household products as acidic or basic.
5. Use goldenrod indicator paper to test for acids and bases. For over 150 years litmus
paper has been used to test the acidity of a solution. Now you can use goldenrod paper in
the same way.

Note: You can change red litmus paper into blue litmus paper by soaking the red paper in a
weak solution of a base, such as, baking soda, NaHCO3 and allowing it to dry.
Note: You can change yellow goldenrod paper into red goldenrod paper by soaking the
yellow paper in a weak solution of a base, such as, baking soda, NaHCO3 and allowing it to

Suggested Activity: Provide students with the above litmus paper chart (not the goldenrod
chart), a few pieces of red and blue litmus paper, vinegar, baking soda, and a sheet of
goldenrod paper. The challenge is to prepare a similar type chart for
goldenrod paper.
                   CONTENT                    Curriculum Link       Text/ Section/ Page #
     Cell cycle / mitosis                          9-B1           (9) 2.4 p49/Inv2B p66
-photocopy on card stock; color and cut-out
-sharply crease all diagonal line backward (non-printed sides together)
-sharply crease all vertical lines forward (printed sides together)
-glue the sides together and then bend ends toward each other to tuck in tabs
-hold in place with scotch tape
-carefully print the stage of mitosis shown on each face of the kaleidocycle

               CONTENT                   Curriculum Link
 Use for creating shrinking cells;          Gr 9 bio
  magnification calculations
This is used as a two day lab. The first day, the students experiment in groups with percent
reduction of polystyrene using different geometric shapes. Next they design individual
projects and calculate what the preheated dimensions need to be using what they learned
the first day.

    scissors
    rulers
    balance
    permanent markers
    polystyrene - PS - (recyclable #6) plastic: salad trays, bakery boxes, etc.
    tray covered with aluminum foil
    spatula
    toaster oven
    pot holder
    hole punch
    two ceramic tiles (optional)

Advance Preparation:
    Collect enough items made of recyclable plastic #6 for each student to have one.
    Preheat the toaster oven to approximately 300° F. (Will vary from oven to oven.)

1. Draw the following geometric shapes on the board: circle, square, rectangle, triangle,
   and a rhombus. Have the students provide the formulas for calculating the area of each
   shape. Divide the students into 5 teams and assign each team one of the shapes. Each
   team is to cut out the largest shape possible from their piece of plastic. They are to
   measure the dimensions, calculate the area, and find the mass of their geometric shape
   and record all data on the board for all students to copy into their journals. Students
   should make observations about the plastic in their journals (color, thickness, rigidity,
2. Shrink each shape using the preheated toaster oven. Place the piece of polystyrene on
   an aluminum foil covered tray and place it in the oven. It should take about a minute.
   It will sometimes curl up as it heats. Once it has uncurled, it can be removed from the
   oven. Watch it carefully. Sometimes it will curl up and ―stick‖ to itself. You can
   usually ―undo‖ it by manipulating it with forks if it doesn’t harden too quickly. Use the
   spatula to flatten it while it is still hot if still slightly curled. Pressing the piece between
   two ceramic tiles works very well.

3. Have the students measure the dimensions, calculate the area, and measure the mass of
   their geometric shapes again. They should record the ―after heating‖ data on the board
   for all students to copy into their journals. Once again, have them make observations
   about the plastic in their journals.

4. Have students calculate the percent reduction and the percentage of plastic area
   remaining or represent the area of the shrunken shape as a fraction of the original area.

5. On the second day, the students design individual projects (key chains, pendants,
   earrings, Christmas ornaments, luggage tags, etc.). They draw the design in their
   journals showing the dimensions they wish their final project to have. Using the
   information gathered in the team activity, they determine what the original dimensions
   of their plastic will need to be. Have them make the object and compare the size of
   the completed project with their original drawing. Permanent markers may be used to
   add color and create designs. A hole punch can be used to make key chains luggage
   tags. Hint: You might want to demonstrate this for them. One punch shrinks too much
   to fit most key rings so usually multiple over-lapping punches are needed. Be sure to
   punch the holes before the shrinking process.

The plastic used in this activity (polystyrene) is easy to work with when heated. While hot,
polystyrene can be stretched into any shape required. Normally, the polymer chains in a
piece of polystyrene are jumbled together in an almost random way (think of wet spaghetti
noodles dumped on a plate). When heated, the strands can be stretched into a more
ordered pattern and ―frozen‖ in place. If the polystyrene is reheated, it returns to its
original shape (a type of ―memory polymer‖.) A plastic that softens upon heating and can
be reshaped is known as a thermoplastic. Thermoplastics can be melted or softened to
make new products and thus are recyclable. They include polyethylene, polypropylene,
polyvinyl chloride (PVC), and polystyrene (PS). Products and packaging made from one of
these thermoplastics are stamped with the recycling symbol – a triangle of arrows with a
number (1 – 7) inside.

Polystyrene is not the only plastic that behaves this way with heat. Soda bottles are also
made from plastic with similar qualities (recyclable #1 - PETE). Soda bottles are
transported as ―pre-forms‖. A pre-form is a rigid piece of plastic the size and shape of a
large test tube. When it gets to the bottling plant, it is heated and expanded by blow
molding into the desired size.
High density polyethylene (HDPE) bottles help to demonstrate the concept of
thermoplastics. HDPE is recyclable #2. Sunny Delight bottles and half gallon or one gallon
juice, milk, and distilled water jugs are usually #2. Heat the side of a clean #2 bottle with
a heat gun until it softens and becomes more transparent. Then gently blow into the
opening and watch it expand. It is a simplified demonstration of blow-molding.

This activity can help illustrate the Law of Conservation of Matter (mass).

Students may also measure thickness (both before and after heating) with calipers. This
will allow them to calculate the percent change in thickness and also compare volumes.
More math calculations!!!!!!

This activity was performed after comparing the solubility of natural (starch) and synthetic
(foamed polystyrene) packing materials in water and acetone. Thus the monomer and
formation of polystyrene had already discussed. Also, a burn test was done on both foamed
and non-foamed PS. Of course the students wanted to try shrinking a Styrofoam cup. It
works very well. The kids are amazed by how hard and brittle it becomes. (Have plenty of
cups on hand because they will want to try it more than once - right-side-up, up-side-down,
on its side, etc.). The clear polystyrene drinking cups found in some motel rooms also work
well. They shrink into nice little Frisbees. Dollar stores often have packages of 5 oz.
drinking cups made out of polystyrene. They shrink into flat circles and are very
inexpensive. They make great backpack tags, luggage tags, etc.

Have plenty of PS collected because the students will end up wanting to make more than
one project. They love watching it shrink - they describe it as ―looking like slugs when you
pour salt on them‖.

On the average, between 80% and 90% reduction in area occurs.

If the students make key chains, the holes need to be large and away from the edge.
Otherwise they will not be big enough or they will break from the weight of the keys.

The students love this activity (despite all the math calculations) and don’t want to stop. It
is a great activity to do at the end of school or before a holiday. Not a single problem with
discipline or keeping the students on task (other than fighting over the PS if the supply runs

Websites where sheets of polystyrene can be purchased:
              CONTENT                     Curriculum Link
 Light, refraction                         Gr 8 Optics

What is needed?
   Four or more Pyrex glass stirring rods; you could also use anything made from Pyrex
  including kitchen measuring cups
   Two clear plastic or glass containers.
   One container of Wesson Vegetable Oil or Canola Oil
   Tap water
What to Do
Fill one of the jars about half way up with tap water. Put two of the glass rods into the
water. Look through the jar at the rods. You can see them fairly clearly.
Next, fill up the other jar half way full with the Wesson Oil. Now put the Pyrex glass rods
into the jar. Look through the jar at the rods. Notice that the rods have disappeared. They
are practically invisible in the oil.
What is Happening?
This experiment introduces you to the concept of index of refraction. The index of
refraction of a material is a measure of how fast light travels in a material. If light goes
from one material to another, and the two materials have different indexes of refraction,
the light is bent. When two materials (like glass and air) are in contact and light shines
through them, the light bends a little at the surface separating the two materials. The
reason that the light bends is because the index of refractions are different for air and
glass. When light goes from air into glass, this happens. This is why you can see the glass
rods in air!
Now, if the two indexes of refraction are not too much different, the light does not bend
too much. When the Pyrex rods were in the water, you could still see them clearly because
the index of refraction of Pyrex and water are slightly different. When the Pyrex rods are
put in the Wesson vegetable oil, the story is quite different. The rods are practically
invisible in this oil. This is because the Wesson Oil and the Pyrex rods have practically the
same index of refraction. The light that is traveling through the jar into your eye is not
bending at the surface of the glass. Therefore you cannot see the Pyrex rods.

Other Things to Try
A related phenomenon to index of refraction is scattering. Look at a soap bubble floating in
the air. The soap itself has little color to it, the air inside is 'clear', and the water is also
'clear'. Why can you see the soap bubble? What happens when you get thousands of little
bubbles together like soap foam in the kitchen sink?
               CONTENT                  Curriculum Link
 Light, human vision; structure of        Gr 8 Optics
When held stationary, this ball appears to glow with a nearly white light. When spun in a
circle by the cord, one can see the white light separate into blinking red, blue, and green
lights, the primary colors of light.

Directions: Turn the light on by twisting the battery plug clockwise. Darken the room.
Place two fingers from one hand through loops on the cord. Making sure there is enough
room on either side, above and below you, swing the ball in a circular path in front of your
body. People in front of you will observe the results.

To Do and Notice:
    Turn the light on by twisting the battery plug clockwise. Describe what you see once the
light is on. Now place two fingers from one hand through loops on the cord. Making sure
there is enough room on either side, above and below you, swing the ball in a vertical circle
in front of your body. People in front of you will observe the results. Now have someone
else swing the ball so you can watch the ball as it moves.
    • What three colors do you see when the ball is motion?
    • What does this tell you about the colors needed to produce white?
    • Why do you suppose all three colors behave as if they were ―on‖ all the time when the
ball is stationary even though the lights are blinking?

What’s Going On:
    When the ball is spun in a circle, one can see the white light separate into blinking red,
blue, and green lights, the additive primary colors. When the ball is at rest, the
combination of red, green, and blue light makes white. To the eye/brain system, the three
colored lights seem to remain on when the ball is stationary, even though each is blinking.
This is due to the ability of our visual system to retain the impression of a light for a short
time after the light has disappeared. This physiological phenomenon is called persistence of
vision. This effect is familiar to anyone who has ever looked into a camera flash.
    Besides additive color mixing by overlapping red, green and blue lights, it is also
possible to obtain most colors, including white, by placing the primary colors so close to
each other that the eye cannot see them as separate. This type of additive mixing,
sometimes referred to as optical mixing, is used in the production of images by color TV
tubes and computer monitors and also by pointillist painters such as Seurat.
             CONTENT                   Curriculum Link
 Light, comparison of EM spectrum       Gr 8 Optics


This activity explores the temperature behavior of UV sensitive beads and investigates the
effectiveness of sunscreens. UV Beads are a type of sensor that detects ultraviolet light
given off from the sun. When UV beads are exposed to sunlight, they react by changing
colors. UV beads can do this because they contain certain pigments that change color when
exposed to sunlight or other forms of ultraviolet radiation. Exposure to UV radiation is
harmful to skin cells. Sunscreens contain substances that absorb UV radiation and their sun
protection factor (SPF) indicates how effective they are.

   Identify the properties of UV beads as a sensor which switches ―on‖ and ―off‖ with
       exposure to UV light.
   Recognize the wavelengths of radiation that reach the surface of the earth.
   Discover how sunscreen works and the importance of using it when exposed to the

    UV Beads
    Access to sunlight (such as a window) or UV light
    Aluminum foil
    Cookie sheet
    Oven
    At least 2 types of sunscreen including: SPF 8, SPF 15, SPF 30, and SPF 45 sunscreen
      (if only two are available, preferably higher and lower ends of the range)
    Fresh water and salt water
    3 small drinking glasses
    plastic wrap
    scissors
    white paper
    cotton swabs
    timer (such as a watch)

Before starting the activity, look at the UV beads and identify their properties.
    What color are they?

      Take one UV bead outside (or to a window or UV lamp) to see how light affects the
       bead. Describe what happens:

      Next, take the UV bead back inside, describe what the UV bead looks like as you
       bring it back inside:

Now, prepare your UV beads for the activity:

   1. Pre-heat the oven to 350 degrees.
      Safety: Make sure your parents are present when you are doing this activity! The
      oven gets very hot. Have oven mitts handy for taking your UV beads in and out of the

   2. Take a cookie sheet and cover it with aluminum foil. Do not put the UV beads
      directly onto the cookie sheet. Make sure to leave space (at least 1 inch) in-between
      your UV beads so they do not stick together. UV beads are plastic and could
      permanently damage the cookie sheet if aluminum foil is not used.

   3. Place the UV beads on the oven for 10 minutes or until they flatten to the size of a

   4. Remove the beads from the oven and allow them to cool for at least an hour.


I: Exposing UV beads to a light source (sunlight)
    1. Lay the UV sensitive beads on a piece of white paper. Use 4-5 different colors.
    2. Expose the UV beads to the sunlight, write your observations for each disk.
    3. Bring the UV beads away from the sunlight and observe the color of each UV bead.
    4. Repeat this process 2 more times.
   5. Use the table below to record your observations:

UV bead       Color 1:     Color 2:      Color 3:      Color 4:     Color 5:
Color the
UV bead
Time of
change (in

   Are some color changes easier to see than others?

      Based on your observations, which color disk is the most effective at sensing UV

       ->Now, we will experiment with one color only. Collect 6 disks of any color
         (only one color) for the next group of experiments.

II. Using UV Sunscreens to test the effectiveness of sunscreens
    1. Draw 4 circles on one piece of white paper.
    2. Label one disk ―control‖ and place one of the UV beads in it (use the color that you
        selected earlier).

   3. Take another disk of the same color and use a cotton swap to apply sunscreen to the
      UV bead. Make sure to cover the entire surface of the UV bead. Label another circle
      with the SPF number of the sunscreen you used and place the UV bead into the
   4. Repeat step ―3‖ two more times with sunscreens of differing SPF values.
   5. Expose all four disks to the sun for 2 minutes. Develop a scale of 1-5 to explain the
      variation of colors of the UV beads when exposed to sunlight. On this scale, 1 is the
      lightest color, 5 is the darkest color.
   6. Repeat the process two more times. Each time you repeat the process, use a new
      bead and reapply the sunscreen (using the same SPF values. However, keep your
      control bead the same.
   7. Record your results below:

Color bead      Control bead    Bead 1: SPF #    Bead 2: SPF #   Bead 3: SPF #
changed to                      _________        _________       _________
(Scale 1-5; 1
lightest, 5
Trial #1

Trial #2

Trial #3

**As an extension, repeat Activity II using another color and compare the data to your
results from the first color you used.

Is your sunscreen really waterproof?
       When you go swimming, does your sunscreen really stay on your skin? Put the UV
bead into fresh or salt water for 2 minutes. Use a cup for each bead and label that cup
either as ―control‖ or using the SPF that you used for each bead. You may use the same
beads that you used for Activity II. After 2 minutes, take the bead out of the water and
repeat Activity II. Record your data using the table below.

Color bead      Control bead    Bead 1: SPF #    Bead 2: SPF #   Bead 3: SPF #
changed to                      _________        _________       _________
(Scale 1-5; 1
lightest, 5
Trial #1

Trial #2
Trial #3


Home Made Sunscreen:
Obtain USP grade titanium oxide or zinc oxide (available from compounding pharmacies),
almond oil (or other good oil) and beeswax. Use 1 cup oil to 1 oz beeswax and 1-2
Tablespoons zinc or titanium oxide. Heat the oil just enough to melt the wax (grate or chop
it first), then add the titanium or zinc oxide.

UV beads:

Sunscreens and SPF:

Light, UV Light and the Electromagnetic Spectrum:
              CONTENT                   Curriculum Link
 Fluids and dynamics; forces               Gr 8 C5
Place three seemingly identical spheres on a horizontal track touching each other. Roll
another sphere slowly into the spheres at rest. Wow! All of a sudden the last sphere takes
off with tremendous velocity. The system seems to have gained energy!

Track, five metal spheres and one magnetic metal sphere.

Teacher Note:
The kinetic energy and the momentum of the initial moving spheres are transferred to the
final moving spheres. In this case, in order for both the Law of Conservation of Momentum
(mv) and the Law of Conservation of Kinetic Energy (1/2 mv2) to hold, the initial moving
spheres must equal the final moving spheres "What comes in is what goes out." Deviations
are due to friction, and the slight magnetism of the spheres, causing them to stick together
slightly and not roll well. What did you observe?

As the released sphere gets closer to the stationary magnetic sphere at the bottom of the
track, it becomes more and more attracted to the magnetic sphere. This causes a great
increase in velocity. As a result, the sphere on the other end shoots out quickly. Notice that
the final moving sphere is initially separated by another sphere from magnetic sphere.
Consequently, it is attracted less to the magnetic sphere.

Caution: the strong magnetic sphere is ceramic and may crack if dropped onto a hard
              CONTENT                Curriculum Link
 Fluids and dynamics; forces            Gr 8 C5
     A cylindrical neodymium magnet (check out Lee Valley Tool) and a 1m length of
       copper pipe.

In response to the falling magnet an electrical current is produced in the copper tube. The
result is a temporary electromagnet that opposes the motion of the falling neodymium
magnet. This slows its fall through the tube. This principle is used in damping the
oscillation of the lever arm of many mechanical balances. At the end of the arm a piece of
flat aluminum is positioned to move through the magnetic field of a permanent magnet.
The faster the arm oscillates, the greater the current and the greater the attraction to the
permanent magnet. However, when the arm comes to rest, the attraction is negligible.

Determine the time it takes for one magnet to fall down the one-meter copper tube.
Calculate the average velocity of the magnet based on the time and the tube length.
Assuming the velocity of the falling magnet to be constant, calculate the time it takes the
magnet to fall in the shorter tube of the same thickness.
              CONTENT                    Curriculum Link
 Fluids and dynamics; forces;               Gr 8 C5
  balanced forces

     hammer with a wooden handle
     wooden or plastic ruler
     short string or wire
1. Take a flat wooden or plastic stick (the length of a ruler) and hang the hammer (with a
wooden handle) with the iron part of it down, by means of a string.
2. Make a loop out of the string or wire (about 10 cm diameter), and slip it around the ruler
and the handle of the hammer (let the end of the handle press against the ruler end).
3. Let the other end of the ruler hang from the edge of a table top.
1. What made the heavy hammer stay up at the edge of the table?
2. Why do we need a hammer with a wooden handle?
3. Can we consider the ruler really to be loose?
4. Where is the center of gravity of the hammer alone?
5. Where is the center of gravity of the whole system of ruler, string, and hammer?
6. What is the difference between a stable and labile system?
This demonstration can only be carried out when the hammer has a wooden handle, as the
center of gravity is located in the iron part of the hammer. The plastic or wooden ruler and
string do not add much to the weight of the system on the handle side. They make the
position of the center of gravity of the whole system shift just a little towards the right and
If this center of gravity is under the pivot point (point of support), it is a stable system. If
the center of gravity is above the pivot point, it is a labile system and it falls.

Invitations To Science Inquiry, 2nd Edition, by Dr. Tik L. Liem, Demonstration 13.9
              CONTENT                    Curriculum Link
 Fluids and dynamics; forces;               Gr 8 C5
  balanced and unbalanced forces

Does a glass get heavier if you put your finger in the water? Find out in this experiment.
What you need: 2 plastic glasses; String; A stick or ruler; Alternatively use an electronic
balance and a container.

What to Do

The idea is to build some scales with a glass of water on each side. So first you want a way
of attaching the cups to some string. One way of doing this is by cutting two holes in
each cup slightly below the rim. Then tie the cups to the stick, and a piece of string in the
centre of the stick. Now fill the two glasses almost full. Add water so that the stick
balances when hung from the centre piece of string. Put your finger in one cup without
touching the sides. What happens?

What may Happen
You should find that the cup you put your finger into moves
One way of thinking about this is that if you put anything in water - a boat, a rubber duck
or just your finger, it will feel an upthrust force pushing up on it. This is the force which
makes boats float and is equal to the weight of water that is displaced by the object. Issac
Newton worked out that if you apply a force to something you will feel an equal and
opposite force (every action has an equal and opposite reaction). So if the water is
applying an upwards, up-thrust force to your finger, your finger must be applying a
downward force to the water. Another way of thinking of it is that when you put your finger
in the water it will increase the level of water in the cup. This means that there is more
water pressure at the bottom of the cup acting on the same area, so there is a greater
             CONTENT                    Curriculum Link
 Water systems on Earth;                  Gr 8 D1-3
  properties of water

A screen-covered jar is filled by pouring water into it. But when it is inverted, the water
remains inside! Students discover what makes this phenomenon possible.

Science activity appropriate for grades 1–12
Cross-Curricular Integration intended for grades 4–6

• adhesion and cohesion                           • properties of water
• atmospheric pressure                            • surface tension
• intermolecular forces of attraction             • gravity

Before doing this activity students should have previous
experience with other activities that involve surface
tension, air pressure, and gravity

• observing Students observe the One-Way Screen
apparatus as they manipulate it in different ways.
• communicating Students describe what happens in the
activity and discuss their observations.

Setup 10 minutes
Performance 5–10 minutes
Cleanup 10 minutes
One-Way Screen apparatus

For “Getting Ready” only
Per group of 3–4 students
• canning jar with screw ring or wide-mouthed plastic
container with plastic lid (Younger students will find
smaller containers easier to handle.)
• mesh screen (large enough to cover the jar mouth)
used for window screens
• scissors to cut screen
• marker

For the “Procedure”
Per group of 3–4 students
• One-Way Screen apparatus prepared in ―Getting Ready‖
• card (large enough to cover the jar mouth)
• container filled with about 1 L water. A “pop-beaker” made from a cut-off plastic 2-L
soft-drink bottle works well.
• plastic tub or bucket
• (optional) toothpicks thin enough (trimmed if necessary) to fit through screen
For the “Variation”
Per group
All materials listed for the ―Procedure‖ plus the following:
• different types of cloth, including cheesecloth
• rubber band

For the “Extensions”
➊ All materials listed for the ―Procedure‖ plus the following:
Per class
• soap

➋ All materials listed for the ―Procedure‖ plus the following:
Per group
• screen with different mesh sizes

➌ Per class
• 1 or more cloth umbrellas

Safety and Disposal
The screen can cause small scratches. If using glass containers, caution students to handle
them carefully. No special disposal procedures are required.

Prepare a jar for each group:
1. Use a marker to outline the lid on the screen.
2. Carefully cut the screen so it is neither too small (and not held by ring) nor too large
(causing the screen to buckle once put into the ring.) If using plastic jars/lids, cut (or melt)
out the top of the lid, leaving enough lip around the edge to grip the screen.
3. Place the screen over the mouth of the jar and screw on the ring or cut-out lid.

Introducing the Activity
As a demonstration for the class, do Steps 1–8 of the ―Procedure‖ without the screen. Be
sure to include Steps 2 and 6, which allow for class predictions. This demonstration
provides students with a point of reference to the activity and allows them to see it as a
discrepant event. You may also choose to do a demo with the screen in place. First fill the
jar by pouring water through the screen, put the card in place and invert. Many students
have seen this one before, but will be amazed when you remove the card and the water
stays in the jar.
1. Give each group a One-Way Screen apparatus and a plastic tub or bucket.
2. Ask students to predict what will happen if water is poured onto the screen.
3. Holding the apparatus over the tub, have a student from each group pour
water through the screen until the jar is completely full.
4. Tell a student from each group to put the card on top of the screen and hold it down
tightly with one hand.
5. Instruct the students to use the other hand to invert the jar while keeping it over the
tub. The jar must be in a vertical position, not tilted at an angle.
6. Ask students to predict what will happen if they remove the card from the screen.
7. Tell students to carefully slide the card from the screen.
8. Ask students to describe what happens to the water. Be sure that they look closely at the
bottom of the screen.
9. (optional) Suggest that each group push a toothpick through a hole in the screen. ―What
happens?‖ The toothpick passes through the hole and floats to the top of the jar, yet little,
if any, water comes out. ―What does this reveal?‖
No unseen barrier is covering the screen and preventing water from running out. ―If the
screen is permeable to large objects like toothpicks, how can it hold back the water?‖
10. Ask students to tap the screen with a finger. ―What happens?‖ If water does not gush
out of the jar, have the student slowly tilt the jar to one side until the water flows out.
11. Have groups discuss their observations and formulate plausible explanations.

The following explanation is intended for the teacher’s information. Modify the
explanation for students as required. As illustrated in the introduction, when an open jar
of water is inverted, the water falls out (as expected) because of the downward pull of
gravity on the water; however, with                                                 the
screen on the jar, the water seemingly                                              defies
gravity by staying in the jar.
Of course, the conditions are not
identical in these two cases. A close
examination of the inverted apparatus                                               (Step 8)
shows that little half-dome drops                                                   project
from the small holes in the screen.                                                 (See
Figure 1.) This shows that while the                                                water
can come through the screen, its                                                    further
movement is somehow hindered and                                                    the pull
of gravity is overcome. This
―antigravity‖ effect can be explained                                               in terms
of the nature of water and of air

Figure 1: Half-dome drops project from small holes in the screen.
All matter is made up of tiny particles. An important feature of the particles of a liquid is
that they are close enough to one another for the attractive forces to hold the particles
together. These forces are called intermolecular forces of attraction.
(―Inter‖ means ―between.‖) Water particles have an especially strong attraction for one
another. The attraction between particles of the same substance is called cohesion. Water
particles also have a strong attraction for particles of some other substances, such as glass.
The attraction between particles of different substances is called adhesion. Another
property of water is that its surface behaves as if it were an elastic film because of
cohesion between its particles. The measure of this elastic-like force existing at the surface
of liquids is called surface tension. The surface tension of a liquid is the amount of energy
required to stretch or increase its surface area; the surface tension of water is very high.
A final factor affecting the system results from the air acting as a fluid.
Atmospheric pressure exerts its force in all directions, helping support the water inside the
jar. But in spite of the forces of cohesion, adhesion, and air pressure, water still falls out of
an open inverted jar. If the size of the opening decreases sufficiently, the strength of the
forces can be larger than the gravitational force and the water does not fall out. With the
One-Way Screen apparatus, the\screen provides lots of surface to which the water particles
can adhere. Similarly, in the ―Variation‖ and in Extension 3, the ―holding‖ materials
provide enough surface forthe water particles to adhere and not pass through.
Although the surface of water behaves like an elastic film, the initial pouring of water
through the screen and putting the toothpick through the hole in the screen provide
evidence that no separate invisible film holds the water in the jar. Pulling a finger away
from the outside of the screen (when tapping on it) adds an adhesive force in the direction
of gravity and the water falls out of the jar. When soap (a surfactant) is added to the water
as in Extension 1, the soap particles come between the water particles and disrupt the
strong cohesive forces; thus, soapy water will not be held back when the container is
inverted because the surface tension is reduced.
Have each group fill a jar with water and wet a small cloth. Have each group place the wet
cloth over the top of a jar of water and attach with a rubber band. Have them turn the jars
upside down. ―Is the cloth waterproof?‖ Try this with different types of cloth including
1. Have students redo the ―Procedure‖ with a little soap added to the water. ―Is the One-
Way Screen still effective?‖
The soapy screen will not work subsequently as a One-Way Screen without being rinsed
numerous times.
2. Have the students use screens of different mesh size to find how large the holes can be
and still function as a One-Way Screen.
3. The next time a gentle rain is falling, take your students outside with one or more cloth
umbrella(s). Ask students, ―What keeps the rain from coming through the cloth? Can you
blow air through the cloth? What kind of ―skin‖ does an umbrella have? How does a cloth
tarp on a truck work? How does a cloth tent keep the rain off the campers?‖
NO-POP BUBBLES – use to demonstrate static electricity
Blow No-Pop Bubbles up into the air. Observe the colors (interference patterns) in the
bubbles as they float. In approximately 10 seconds (depending on the relative humidity),
the colors will begin to disappear. When the bubbles are colorless, they may be caught on
your finger without popping! Blow No-Pop Bubbles outside and watch how they glimmer on
the grass of your school field. In a dry environment, No-Pop Bubbles will last for weeks!

It's all in the solution.
At first glance, No-Pop Bubbles may seem like any other bubbles. While the bubble solution
is a bit more viscous, one blows No-Pop Bubbles like any other bubble. The small bubble
wand suspends a bubble film which, when air is blown through it, releases small bubbles
into the air. These bubbles, however, are no ordinary bubbles.

What are No-Pop Bubbles?
No-Pop Bubble solution begins as a regular soap and water bubble solution. To this is added
a small amount of a non-toxic water soluble polymer. When No-Pop Bubbles are first blown,
the bubbles behave like ordinary bubbles. As water evaporates from the bubble's surface,
however, an extremely thin plastic 'bubble skeleton' remains. It is this plastic bubble
skeleton which has the properties for which No-Pop Bubbles are named.

Activity #1: Bubbles and Static Charge
1. Inflate an ordinary rubber balloon.
2. Blow a bunch of No-Pop Bubbles into the air.
3. While the bubbles are 'drying', rub the balloon vigorously on your hair in order to develop
a static charge.
4. Use the charged balloon to attract the No-Pop Bubbles.
5. Observe how the bubbles behave before and after they are in contact with the charged
6. Experiment with other static sources, rods, or Van de Graaf generators, etc.

Activity #2: Observing Air Currents
1. Blow lots of No-Pop Bubbles outside, next to your school building on a windy day.
2. Observe how the bubbles float and fly in the air currents as the wind blows around the
3. See if you can find mini-tornados of air!
            CONTENT                     Curriculum Link
 Comparison of series and parallel           9-C7

Touch-N-Glow Ball

The Energy Ball may look like a simple ping-pong ball with two pieces of metal, but when
both pieces of metal are touched simultaneously, the ball lights up and makes noise.

   1. Touch one metal contact. What happens?
   2. Touch both metal contacts at the same time with the same hand. What happens?
      What happens if you use two hands? A hand and a toe?
   3. Touch one metal contact. Have a partner touch the other. What happens?
   4. Touch one metal contact. Have a partner touch the other with one hand, and have
      him/her touch your hand with the other. Does the ball light up?
   5. Touch one metal contact. Have a partner touch the other with one hand. With the
      free hand, have each person hold a piece of metal. Does the ball light up?
   6. Touch one metal contact. Have a partner touch the other with one hand. With the
      free hand, have each person hold a piece of plastic. Does the ball light up?
   7. Have two students each touch one of the metal contacts. Have the rest of the class
      hold hands (or make some kind of contact) with each person touching the metal
      contact in the circle. Does the ball light up? How big can you make the circle?
   8. Take two energy balls and line them up so that a metal contact on ball A is touching
      a metal contact on ball B. Touch each of the other metal contacts (one from each
      ball). Does it light up?
   9. Have two students touch one of the metal contacts. Have each student put a finger
      of the other hand in a glass of water without their fingers touching. Does it light up?

How does it work?
You should have observed that the ball lights up and makes noise when it is touched by the
same person or by two people touching each other. The Energy Ball contains two exposed
contacts and a small amount of electricity. The electricity cannot be used to turn on the
light in the Energy Ball unless the electricity can move freely from one metal contact to the
other. By touching each contact, you are completing an electrical circuit in the Energy Ball.
If electricity can move from one piece of metal to the other, the circuit is closed and the
ball will come to life.

You may know that tap water is an excellent conductor of electricity. (That’s why you
shouldn’t go swimming when there is lightning—the electricity from the lightning can travel
through the water and shock you.) The human body is about 65% water with salt dissolved
in it, so the electricity can travel through a human from one contact to the other. When we
perspire a layer of salt water is on the outer layer of skin. Most metals conduct electricity,
which is why two partners holding a piece of metal can make the ball light up. Plastic, on
the other hand, does not conduct electricity. Anything that does not conduct electricity is
called an insulator. When an insulator blocks the flow of electricity from one metal contact
to the other, the ball does not light up.
The word ―circuits‖ sounds like another word,
―circle.‖ This is not a coincidence. A circuit is a
closed circle through which electricity flows. If
there is a break in the circle or circuit, the
electricity cannot flow through it. When you flip
a light switch to the ―on‖ position, the electrical
circuit is closed, so the light can turn on. Turning
the light switch to the ―off‖ position creates a
break in the circuit, turning off the light.

Fun Facts
    Light bulbs work in much the same way as
       an Energy Ball. The filament in a light bulb
       (the small wire that emits light in the
       middle of the bulb) provides the
       connection to close the circuit. A dead light bulb stops emitting light because the
       filament breaks and the electricity cannot travel through it.
Insulators like certain kinds of rubber are used to cover electrical cords so that they are
safe to touch. Be careful not to touch an electric cord that does not have an insulator.
Properties of Matter
             CONTENT                     Curriculum Link
 Conservation of mass; No law of          Gr 10 Chem
  volume conservation

Hydrophilic water gel Growing Crystals are made from a polyacrylamide polymer with a
strong affinity for water. Chemists call this property hydrophilic. A hydrophilic substance is
one that takes up water easily – just as a dry sponge might if dropped into a pail of water.
If placed into water, Growing Crystals will absorb water and swell to several hundred times
their original size. Because the amount of water Growing Crystals will absorb depends on
the salt content of the water, we suggest you use pure clean water from the tap.
To prepare Growing Crystals, simply place them in clean water and allow them to sit. While
you may be able to observe some changes within just a few minutes, the crystals take
between two and eight hours to reach their maximum size. Hot water may be used to speed
up the process. To color the crystals, food coloring may be added to the water prior to
adding the crystals. Approximate mixing proportions are one gallon of water for two
tablespoons of Growing Crystals, or 250 mL of water for 1.5 teaspoons of Growing Crystals.
Once fully expanded, Growing Crystals have an index of refraction almost identical to that
of water. This means that when the clear, colorless, expanded hydrophilic polymers are
placed in water, they are nearly invisible. It is difficult to see the crystals in water because
light rays are not bent when they travel between two substances with the same indices of
refraction. Growing Crystals may be dried and expanded again and again. Simply spread the
expanded crystals on a flat surface and allow them to dry. When they have returned to
their original size, store them in a plastic bag or container. It is recommended that you use
distilled water if you intend to reuse your crystals.
Disappearing Crystals:
Tie a thread around a single expanded crystal. Lower the crystal into a cup of water and
make an observation. This can be done on an overhead projector as a demonstration for an
entire class. Try carefully pushing a small nail or thin wire through the crystal. When
lowered into water, the nail or wire appears to be completely suspended.
Growing Bulbs:
Grow flowering bulbs in the clear expanded crystals. This allows you to see the roots as
they grow. Simply expand the crystals by placing them in clean water overnight. Pour off
any excess water and plant your bulb, stem side up, about ½ way into the crystals.
Remember to use a clear container and to keep your crystals out of direct sunlight.
(Paperwhite bulbs work the best!)
Important Notes:
While Growing Crystals are generally considered to be non-toxic, they should not be
consumed!!! Growing Crystals are sensitive to direct sunlight. Exposure to direct sunlight
will decompose the polyacrylamide polymer and slowly destroy the crystals' ability to
absorb water. (Teachers, this might make for a good experiment!)

            CONTENT                      Curriculum Link
 Demo conservation of mass but            Gr 10 chem
  no conservation of volume

Immediately after hydrating the snow polymer have students touch the expanded material.
It should be slightly warm to the touch as the reaction between the water and the polymer
produces heat. If students touch a sample of snow that was previously expanded (10
minutes or more) they will find it cool to the touch. Question students as to why this might
be, (the reason is that the water in the polymer is beginning to evaporate and it takes heat
energy for this process to occur).
Have students brainstorm what variables might affect the evaporation rate of the water
over a long period of time. Possible variables might be the size of the container it is left in,
the shape of the container, the temperature of the room, the humidity of the room, etc.
Students should select ONE of these variables to test how the evaporation rate of the
hydrated polymer is affected. All the other possible variables must be kept constant.

Students should design an experiment based on the variable they select to examine. Each
group should have 3 different values to test. For example, if they select the size of the
container the snow is kept in, there should be three different containers. Students should
be sure that the containers are all made from the same material, are kept in the same
area, etc. After the groups have properly planned their experiment they should begin the
data collection stage. Give each group the same amount of expanded snow to use to test
their hypothesis. Over the next two weeks have students measure each of their samples,
using a balance each day and recording the mass on their data table. This should take very
little time, so the remainder of the experiment can be completed for homework. Upon
writing a conclusion, students can be expected to report their findings to the class. This is a
wonderful lab activity to give students a basic understanding of the steps involved in the
scientific method.

In this lab, you and your group will investigate an independent variable to see how it
affects a dependent variable. The dependent variable for all groups will be the evaporation
rate of the water in the snow polymer.
1. Brainstorm a list of variables you think may be important in changing the rate of
evaporation of the water from the snow polymer.
2. Now, with your group, choose only ONE of these variables to be your independent
variable. Record:
3. Write your problem: State as, ―What is the relationship between (your chosen
independent variable) and the rate of water evaporation?‖
4. Write your hypothesis (how you think your independent variable may affect the rate of
5. ALL the variables you listed in #1 that are NOT your independent variable are your
constants. In the space below, please list these variables that you will not allow to change
as you conduct your experiment. How will you ensure that each is unchanged?
6. Now discuss and record the actual design of your experiment, listing procedures you plan
to follow. You’ll need at least 3 trials of at least 3 different values of your independent
variable. Remember to mention keeping the constants and be sure to explain how you will
keep your measurements of the dependent variable accurate. Make a step-by-step,
numbered rough draft of your general lab procedures in the space below.
7. Design a Data Table to record your measurements of a two-week period. (See sample
below) Mass (g) Date Sample 1 Sample 2 Sample 3
8. Create a graph to display your data. Be sure to label your x and y axes appropriately.
9. Write a conclusion that summarizes the relationship between each change of the
independent variable and the dependent variable. A reasonable explanation of your results
should be included.
Magic Sand, contrary to its name, is not magic. Magic sand is, in fact, normal sand that has
been covered in a special coating: trimethylhydroxysilane, (CH 3)3SiOH. This protective
coating is hydrophobic, or ―water fearing.‖ Like oil and water, magic sand and water do not
mix – at all. This gives the magic sand some interesting properties that you and your
students can explore.
First, demonstrate to your students the terms ―hydrophobic,‖ (water fearing) and
―hydrophilic‖ (water loving). The simplest way to do this is to add some food coloring to
water in an empty soda bottle, and then, as your students watch, add oil. The oil and water
will not mix, even when the bottle is shaken, because oil is hydrophobic. The molecules of
oil will bond much more readily with each other than with the water molecules, and
therefore the two substances do not mix. For a fun example of a hydrophilic substance, try
a Gro-Beast. Small dinosaurs and alligators are available at dollar stores and will slowly
grow when placed in water.
Next, introduce your students to magic sand by pouring some on to a piece of paper. Invite
students to touch the dry sand. Ask them if they think the sand will be hydrophilic or
hydrophobic. If you are able, provide some normal, ―non magical‖ sand for comparison. For
an amazing display of magic sand’s hydrophobic property, quickly pour the sand into a clear
container filled with water. The hydrophobic nature of the magic sand allows the sand to
retain its shape under water. In fact, using a stirring rod or even your finger, you can mould
the sand into different shapes. Notice the silver sheen on the surface of the sand.
Challenge students to explain what causes this. The reflection or refraction of light might
enter into the discussion. Another interesting demonstration of Magic Sand’s properties is to
gently tap some sand on the top of a glass of water. If done gently, the water’s surface
tension will cause the magic sand to float on top of the water. Once a thick, even coat of
sand is floating on top of the water, you can try two different experiments. First, gently
press your finger down on the sand, until your finger appears beneath the surface of the
water. This is especially impressive in a glass with clear sides. Remove your finger, and it
should still be perfectly dry. If you press too deeply or quickly, the magic sand may clump
and sink to the bottom. The second experiment also requires a floating layer of sand – once
an even layer is achieved, use a pipet to gently drop water on top of the sand. Your
students will be amazed to see the water bead on top of the sand! Adding enough water
will cause the layer of sand to break and sink.
Play Catch with Water!
Take two plastic spoons and cover them first in rubber cement, then in magic sand. This
creates a hydrophobic surface that can be used toss a drop of water back and forth!
Younger students will love watching and learning about hydrophobic surfaces this way.
How to Destroy Your Sand:
Magic Sand can lose its hydrophobic properties if the special coating on the sand is removed
or damaged. This can be done one of two ways. Oil will readily mix with magic sand, and
this can cause your sand to become ―wet,‖ and you will not be able to reuse the sand.
Common soaps such as dishwater detergent will remove the hydrophobic coating from
magic sand, causing it to become ordinary, hydrophilic sand. While this can make for an
interesting demonstration, please remember that the process is irreversible.
The History of Magic Sand:
Magic Sand was originally created as a way to mop up ocean oil spills. The idea was that
magic sand would repel water but absorb oil and sink to the bottom, allowing the oil to be
dredged from the bottom of the water at a later time. Today, magic sand is used by arctic
utility companies. Sometimes buried equipment in the arctic needs repairs, but frozen
arctic ground is very difficult to dig through. These companies will sometimes bury their
equipment in magic sand, which will not absorb water or freeze, providing easier access to
damaged equipment. (See for details!)
The Future of Magic Sand: YOU!
What uses can you and your students come up with for magic sand? Underwater sandcastles?
Waterproofing sandboxes? The possibilities are endless!
When you’re done with your sand, simply pour as much water as you can from the glass and
then add a small piece of paper towel to the sand. Gently shake the container with the
sand. Remove the wet towel and return the sand to its container for storage. It’s perfectly
dry! Magic Sand can be used over and over again, and stored in the same bottle.

Make Your Own Magic Sand:
This procedure can be used to make a simple form of Magic Sand. This will not be
Materials needed:
Beach sand or horticultural sand (sharp sand); Baking pan; Spoon or stirring rod
ScotchgardTM fabric protector spray
Safety Precautions:
Scotchgard fabric protector must be used in a well ventilated area.
Magic Sand can be reused as long as it is not contaminated with oil-type materials.
Excessive handling will result in the transfer of oils from your skin to the Magic Sand.
After use, pour off as much water as possible. Pour the Magic Sand onto paper towels or
open sheets of newspaper. The paper towels or newspaper will absorb any remaining water.
Pour the Magic Sand into a storage container such as a jar or plastic zip-lock bag.
Experimental Procedure
Preheat an oven to 250°F (120°C). Place some clean sand in a baking pan. Bake the sand,
to remove any water from its surface, for a minimum of one hour.
Remove the sand from the oven and allow to cool. You can work with the baking pan or you
may want to spread the sand on some newspaper in a well ventilated area.
Spray the sand with Scotchgard fabric protector. (Several light coats of Scotchgard are
better than a single heavy coat.) Allow to dry. Stir. Spray again. Allow to dry. Stir. Spray for
a third application. Allow to dry. Test your home made Magic Sand using the investigation
in the first part of this experiment.
Sodium Polyacrylate (Diaper Polymer)
Sodium Polyacrylate is a white granular powder which rapidly absorbs water. It will
instantly absorb from 500 to 1,000 times its mass in water. One of its greatest uses is in
making diapers super-absorbent. Table salt, NaCl, destroys the gel and releases the water.

Suggestions for Use:

1. How much water will a super-absorbent diaper hold?
      Show students a super-absorbent diaper, a glass, and a pitcher of water. Ask
      students how many glasses of water the diaper will hold. While one student is
      holding the diaper open, slowly pour glasses of water into the entire length of the
      diaper. If you are careful, it will hold 7 to 10 glasses of water. One might conclude
      that babies only need to be changed once a day!
      The fibers of the diaper contain a small amount of sodium polyacrylate, which
      instantly gels the water.

2. What’s inside of a super-absorbent diaper? (Good for small groups)
      Over a tabletop, cut a super-absorbent diaper in half and pull out some of the fibers.
      Shake the fibers and pull them apart, allowing the sodium polyacrylate granules and
      fibers to fall onto the table. With your hand, push everything that has fallen into a
      pile. Pick up and discard the top fibers. The white granules that remain are sodium
      polyacrylate, which makes the diaper super-absorbent. Using a dropper, slowly add
      water to the granules and watch the gel instantly form. Show the students a bottle
      of sodium polyacrylate and ask them to predict how many super-absorbent diapers
      could be made with this amount of powder.

3. How many drops of water can you hold on the tip of your finger?
      Ask students to guess the number of drops of water that can fit on one of their
      fingers – usually only a few. Then, with a dropper, show them that you can keep as
      many as twenty drops of water on your fingertip.
      Simply place a few granules of sodium polyacrylate on your fingertip, and slowly add
      the drops of water, allowing one drop to gel before adding another.

4. How good are your powers of observation? – "Three Cup Monty"
      (Good for both large and small groups)
      Start with three tall white Styrofoam™ cups and a pitcher of water. After showing
      students that the cups are empty, fill one halfway with water. Tell students to
      carefully observe the cup with water as you quickly move the cups back and forth.
      Ask them which cup has the water. Then show them that they are correct by pouring
      the water into one of the other cups. Do this several times until finally everyone
      guesses wrong. Simply invert the cup they guessed. Then ask them to guess among
      the two remaining cups. Wrong again, invert this cup on top of the first inverted cup.
      Finally, show them that the water has disappeared by inverting the remaining cup
      and adding it to the stack.
      Beforehand, add a heaping teaspoon of sodium polyacrylate to one of the three cups.
      It is so white no one will notice when you initially show them that the cups are
      empty. In the initial pourings, never pour the water into this prepared cup. Then,
      when you want the water to "disappear", pour the water into the cup containing the
      sodium polyacrylate. The water will instantly gel and stick to the inside of the
      Styrofoam™ cup.

5. Can you invert a glass of water without the water flowing out?
      (Good for both large and small groups)
      Start with two beakers or two clear plastic cups, one of which contains a heaping
      teaspoon of sodium polyacrylate. From a pitcher, pour water into the empty
      container. Holding both containers, one in each hand, pour the water into the one
      containing the sodium polyacrylate. Quickly pour the water back and forth until it
      completely gels. Then invert. To reverse the process and release the water, add a
      few heaping teaspoons of table salt to the gel and stir.

6. Can you follow directions?
      (Good for both large and small groups)
      Pour water into a Styrofoam™ cup, place a card over the opening, invert, and place
      on top of a student's head. Ask the student to hold this inverted cup on top of his
      head. Pull out the card and have the student who is holding the cup read what is on
      the card. It says:
      "DO NOT REMOVE THIS CARD FROM THE CUP!" Pick up the cup and show that the
      water seems to have disappeared.
      Before starting, add a heaping teaspoon of sodium polyacrylate to the cup.
Science Concepts: Polarity, Solubility To see the difference between how polar and non-
polar things dissolve.
A pie plate; 50 mL of water; 50 mL of acetone (this can be replaced with finger nail polish
remover); 3 Styrofoam cups; Styrofoam packing peanuts; small film container
Directions: Procedure A – Packing Peanut Push
1. Place a small amount of acetone in the bottom of a black film container out of sight of
2. Next ask students to guess how many packing peanuts will fit into the film container.
Guesses will be low (1-3 at most)
3. Slowly add the peanuts to the container. The acetone will dissolve each peanut
permitting you too add many more than believed possible.
Procedure B - Bottom Falls Out
1. Give one cup to a person, and you hold the other one.
2. Give the person a cup full of acetone in a glass beaker or jar and you take the one full of
3. Both people pour the "water" into their styrofoam cups. Make sure that the cup with
acetone is held over the pie plate to catch the remains.
4. Observe what happens.
5. Finish by putting the cup into the pie plate and watch it disappear.
Alternate Procedure B - Tower of cups
1. Start with two pie plates and put about a 1/2 inch of acetone in the bottom of one and
the same amount of water in the second.
2. Have a race to see how can make the tallest tower of cups.
3. The cups in the acetone will slowly dissolve and shrink into the acetone, while the ones
in the water will remain intact.

A Styrofoam cup is made of styrofoam. The styrofoam cup is a polymer, and a polymer is a
long chain of monomers. The long chain polymers are held together rather loosely by non-
polar bond interactions between the chains. In addition, the polymer is made as a foam so
there are lots of air spaces between groups of polymers. Styrofoam is a non polar
substance, which means it has no charge to it.
When the acetone was poured into the cup, the cup dissolved. (Avoid saying that the cup
melts, because this is not true). The reason for this happening is because the acetone and
the Styrofoam cup share the same properties, they are both non- polar. Likes dissolves
likes. Non-polar things have no charge, and polar things have positive and negative charges.
The Styrofoam cup didn't dissolve with the water because, they have different properties,
the water is polar, and the cup is non-polar. Acetone is actually what girls use to take off
their nail polish.
Safety: acetone is flammable and poisonous care must be taken.
FUNNY FISH – a simple controlled experiment

The Fortune Fish is a very thin piece of red cellophane in the shape of a fish, 8.9 cm (3.5
inch). When placed in the palm of a hand it twists and curls. It seems to move magically,
different for different people.
Classroom Ideas
1. Place a Fortune Fish in the hand of each student and observe. Ask students to brainstorm
possible causes for the movements.
2. Moisten a small piece of paper towel, ca. 12 cm2 (2 in2), with two drops of water.
Holding the Fortune Fish by the tail and horizontal, slowly lower the head over the
moistened piece of towel, without ever touching the towel. What do you observe? What
happens when you lower the Fortune Fish, held vertically?
3. Use a small piece of tape to fasten the tail of the fish to a table. Bring the moist paper
towel close to its head. A Fortune Fish, which continuously moves up and down, can be
called a Fortune Fish motor. Can you make one? What is the energy source for this motor?
Can you find ways to increase the frequency of the up and down movement? How many
repeating cycles can you observe without touching either the cellophane or the paper
towel? Does the motor work better when the air is warmer or cooler? When covered with a
large glass or not covered?
4. Out of sight of students, place two drops of water on a scrap of rug, ca 20 cm2. Then,
ask students to find the location of the water by using the Fortune Fish as a moisture
5. Discover other uses for the Fortune Fish.

A common incorrect hypothesis is that heat causes the movement of the Fortune Fish. To
show that this is not the correct, hold the tail of the Fortune Fish with tweezers over
something warm. No movement is expected.
When the Fortune Fish is placed in a hand, moisture is absorbed on one side of the
cellophane, causing that side to expand. If only one side expands, the thin cellophane
curls. When the water on the cellophane evaporates, the fish becomes flat.
The Fortune Fish motor absorbs water when close to the moist paper towel and curls
upward. Away from the higher concentration of water vapour, the water molecules are
released from the cellophane and the fish becomes flat. For the Fortune Fish motor to work
there must be a difference in concentration of water vapour, so that water can be both
absorbed and released. Slight circulation of air sometimes helps.

Twist about one inch of thread around each index finger. Bang the hanger on a table or wall
and listen to the sound it makes. Now put your index fingers in your ears and bang the
hangar again. How does the sound change?

The coat hanger hitting a solid object would vibrate and act as the source of the sound.
The vibrations travel through the string and the finger to the ear drum. As the string and
the finger are solids, it is much easier for sound waves to travel through them than through
the air. It is the vibrations of the finger that are immediately transferred to the ear drum
that makes the sound so audible.

Similarly, we place our ear against someone’s chest in order to hear his/her heartbeat.
Singing Rod
When a long metal rod is held in the center with one hand and stroked with the other, a
high-pitched sound is produced.

A. Crushed Rosin
B. Singing Rods (solid aluminum rods 1cm diameter; lengths: 100cm, 80cm and 60 cm)

Procedure A:
1. Firmly hold the center of the
aluminum rod horizontally using the
thumb and forefinger of one hand.
2. Pinch and release a small amount of
crushed rosin with the thumb and
forefinger of the other hand.
3. Gently stroke the aluminum rod from
the center to the end of the rod using
your rosin coated thumb and forefinger.
Repeat and slightly increase the pressure
of your stroking hand until you hear a
high-pitched tone. Too little pressure
will not set up vibrations in the rod; too
much pressure will dampen the sound. It
takes practice!

Procedure B:
1. Firmly hold the aluminum rod
vertically at a point that is ¼ the
distance from the upper end.
2. Repeat Steps 2 and 3 in Procedure A
until you hear a different pitched tone.

Every material has a set of natural vibrations. When you hold the aluminum rod in the
center and stroke it with rosin coated fingers, your fingers slip and stick as they slide along
the rod. This causes the rod to start moving with one of its natural frequencies of
vibration—a half-wave tone. As you continue to stroke the rod, the vibrations increase and
the loudness increases. The node is a place on the object that is not moving. An anti-node
is a place on the object with maximum vibration. Touching a node will not dampen the
sound; touching an anti-node will.

Note: Stroking the rod produces a compression wave within the aluminum in the direction
of the arrows. A transverse wave is drawn for simplicity of representation.
A basic lesson that can be seen immediately is causing the longer of the two Singing Rods to
―sing‖ by holding the center point of the rod and noting its pitch (wave pattern A). Then
take the same rod and hold it by one of the nodes near the end. When the rod begins to
sing, a noticeable change in pitch can be heard (wave pattern B). This will reinforce the
idea of the inverse relationship between frequency and wavelength.
Examine the diagrams above and notice that the wavelength of wave pattern B is half that
of wave pattern A. That means that the frequency is doubled. You may be able to notice
that the higher tone is exactly one octave above the lower.

Note: The tone you hear is not the only wave occurring in the rod. When you force a node
in the center of the rod, higher resonant frequencies with nodes in the center also exist.
The longest wave is the loudest, though, and that is the one you hear. Ex: When you
produce wave pattern A, wave pattern C also exists, although you cannot hear it.

Next, while the rod is ―singing‖ in wave pattern B, grasp it at the mark near the opposite
end. Since the mark represents the other node in that wave pattern, grasping it there will
not stop the vibration. Touching the rod anywhere else will stop the sound.
Other wave patterns can be produced in the rod (wave patterns C, D, and beyond), but
their pitches are too high for most people to hear.


½ inch PVC pipe cut to the lengths listed below. The pipes can be
marked with permanent marker or fingernail polish. The students
hold the pipe in one hand and strike one of the open ends on the
palm of the other hand, producing the pitch which corresponds to
the length of the pipe.

                            Note      Length      Frequency
                                       *(cm)        **(Hz)
                             A          38.5         220
                             Bb         36.4         233
                              B        34.3           247
                             C         32.3          261.5
                             C#        30.5           277
                             D         28.8          293.5
                             D#        27.1           311
                              E        25.6          329.5
                              F        24.1           349
                             F#        22.7           370
                             G         21.4           392
                             Ab        20.2          415.5
                             A         19.0           440
                             Bb        17.9           466
                              B        16.9           494
                             C         15.9           523
                             C#        15.0           554
                             D         14.1           587
                             D#        13.3           622
                              E        12.5           659
                              F        11.8           698
                             F#        11.1           740
                             G         10.5           784
                             Ab        9.8            831
   * Lengths of these pipes are based on an air temperature of 20° C and 0.5 in
   ** Frequencies taken from

Adapted and expanded from an activity presented by Hugh Henderson of Plano (Texas)
Senior High School at the 2003 AP Physics Institute, Texas A&M University.
                          TWINKLE, TWINKLE LITTLE STAR
                        (Nearly the same tune as the “Alphabet Song”)

         Twin - kle, twin - kle lit - tle star, How I won - der what you are
Melody:  F     F C         C D       D C       Bb Bb A      A G     G F
Harmony: C     C     A     A Bb Bb A G G F                  F E      E C

              Up a - bove the world so high, Like a dia - mond in the sky,
Melody:      C C Bb Bb        A   A G       C C Bb       Bb   A A G
Harmony:     A A     G G      F    F C       A A G        G   F F C

            Twin - kle, twin - kle lit - tle star, How I won - der what you are
Melody:      F    F C         C D       D C       Bb Bb A      A   G G F
Harmony:    C     C     A     A Bb Bb A G             G F      F   E    E C

                                   HAPPY BIRTHDAY

                Hap - py birth - day to you, hap - py birth - day to you;
                C    C D        C F E       C     C D        C G F

                          Hap - py birth - day dear Ein - stein;
                          C    C C         A   F E        D

                               Hap - py birth - day to you!
                               Bb   Bb A        F G F

                                    LONDON BRIDGE

           Lon - don bridge is fall - ing down, fall - ing down, fall - ing down;
           G    A    G     F E       F    G    D      E    F     E     F    G

                   Lon - don bridge is fall - ing down, my fair la - dy.
                   G    A    G     F E       F    B    D G E        C
                 ROW, ROW, ROW YOUR BOAT

       Row, row, row your boat gen - tly down the stream;
       C   C    C    D    E   E     D    E   F     G

      Mer - ri - ly, mer - ri - ly, mer - ri - ly, mer - ri - ly,
      C    C C G          G G E          E E       C    C C

                        Life is but a dream.
                        G F E D C

                    (or Are You Sleeping?)

“Where is Pin - ky? Where is Pin - key?” “Here I am! Here I am!”
  C D E        C     C D E        C       E F G      E F G

     “How are you to - day sir?” “Ver - y well I thank you.”
      G A G F          E C        G A G F E            C

                     Run a - way, run a - way.
                     C G     C    C G     C

          Tonic   W    Third Fourth   Fifth   Sixth   H    Tonic
            C     D      E      F       G       A     B      C
           C#     D#     F     F#      G#      A#     C     C#
            D     E     F#     G        A       B     C#     D
           D#      F     G     G#      A#       C     D     D#
            E     F#    G#     A        B      C#     D#     E
            F     G      A     A#       C       D     E      F
           F#     G#    A#     B       C#      D#      F    F#
            G     A      B     C        D       E     F#     G
           G#     A#     C     C#      D#       F     G     G#
            A     B     C#     D        E      F#     G#     A
           A#     C      D     D#       F       G     A     A#
            B     C#    D#     E       F#      G#     A#     B
            C     D      E      F       G       A     B      C
                                          Great WebSites Lessons, WebTools and teacher resources for teaching science     Check out the teacher resource and student resource areas for
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