Group Activity � CARTESIAN DIVER - DOC by yJ3P74


									                        CLINM WORKSHOP

NAME(S): Lisa Bozzo, Maryam Raymond, Don Angelo

SCIENCE CONCEPT (Main Idea): Students conduct an energy audit
   to determine how much carbon dioxide their classroom is releasing
   into the atmosphere and then make recommendations for
   minimizing the classroom’s carbon footprint.

CONCEPTUAL BACKGROUND: Before talking about energy
  efficiency, it is helpful to have an understanding of units of power
  and energy (like watts, kilowatts, and kilowatt-hours). Power tells
  us the quantity of energy that changed during a certain period of
  time. For example, one watt is equal to one joule per second. A 60-
  watt light bulb converts 60-joules of electrical energy into thermal
  energy (heat) and radiant energy (heat) each second.

CONTENT STANDARDS: Science: 6.3 Heat (Thermal Energy), 6.6
Resources, 6.7 Investigation and Experimentation. Math:

LEARNING OBJECTIVES: Students will be able to:
  1. understand the units of power and energy.
  2. determine the cost of running various classroom and household
  3. find the amount of carbon dioxide emitted for different types of
     energy consumption.
  4. determine ways of reducing energy consumption and carbon
     dioxide output.

  1. formative: class discussions

  2. summative: strategies to reduce classroom energy use, end-of-
     unit test, home energy audit

  1. Make a list on the board of devices and activities that require
     power. Challenge your students to try to rank these activities
     from least to highest power consumption. Next ask the students
     to estimate how much power (in watts) each activity consumes.
     After they have made their estimates, write the actual amounts
     on the board.

    Estimated Power Draw          Activity: Actual Power Draw (watts)
    ____________________          Freight Train: 3,730,000
    ____________________          Hand-Held Flashlight: 1
    ____________________          Incandescent Lamp Bulb: 60-100
    ____________________          Human Sitting Calmly: 75
    ____________________          Human Walking: 383
    ____________________          Human Running: 745
    ____________________          CFL Light Bulb: 13-25
    ____________________          Average Car: 89,520
    ____________________          Space Shuttle Takeoff: 11,000,000,000

    The list shows typical power consumption for various activities,
    but to know how much energy is consumed we have to add in
    the time factor. For example: A light bulb drawing 100 watts of
    power left on for 10 hours consumes 1,000 watt-hours (or 1
    kilowatt-hour) of energy. In other words, WATT (power) tells us
    how hungry a device is for power. WATT-HOUR (energy) is the
    quantity of electrical energy the device used over a period of

  2. Ask students if they know where the energy they use on a daily
     basis comes from. (When students say "the gas station" or "the
     electric company," ask them to go further. Where does the gas
     that is delivered to the gas station come from? Where is the
     power plant that produces the electricity? What type of fossil
     fuel or nuclear source is transformed into the electric energy?)
     Explain to students that energy is power usage over time.
     Power is measured in watts. Electrical energy usage is usually
     measured in kilowatt-hours (kWh—a kilowatt-hour is when 1000
     watts is used for 1 hour).
3. Bring in several electricity bills or find a sample to use (NSTAR
   provides a sample online). Review the bill with students. What
   is charged for in the bill? (There is usually a charge for energy
   consumption and one for energy delivery.) Does the charge for
   a kilowatt-hour remain the same throughout the year? (Charges
   for kilowatt-hours usually vary throughout the year depending
   on how much energy a household uses or whether the energy
   is being delivered during a time of year when energy is in high
   demand. In addition, costs usually vary by region.) In which
   months does the family use the most electricity? (Many families
   use more electricity during the summer months.) What might be
   the reason for this? (Increased air conditioning use is one
4. Tell students they will now calculate how much it costs to run a
   TV all night for a month. To estimate the appliance's energy
   use, have students use the following formula (students should
   find out how much a kilowatt-hour costs in their community):

        Power (Watts) × Time (Hours) = 1 Kilowatt-Hour / 1000
         = Daily Kilowatt-Hour (kWh) Consumption
        Daily kWh Consumption × Cost per kWh = Energy Use

        If a 200-Watt TV were left on 12 hours and each kWh
        costs 10 cents, the cost to run the run the TV for all night
        for one month would be $7.20 (200 Watts × 12 Hours ×
        0.001 = 2.4 Kilowatt-Hours; 2.4 Kilowatt-Hours × $0.10
        per Kilowatt-Hour = $0.24; $0.24 × 30 days = $7.20).

  Now that students are familiar with the concept of watts you can
  do an energy audit. Ask students to estimate how many watts
  the classroom uses on average. Look around the classroom
  and think about all the power being used.

2. Use watt meters or the power consumption chart to tally up the
   total power being used in your classroom.

3. Discuss the results with students. Which appliances use the
   most power? Which use the least? What steps could students
      and teachers take to reduce the power used in a classroom?
      How many watt-hours of energy are used to power this
      classroom for 1 hour? How many watt-hours of energy are used
      to power this classroom for a full school day (8 hours)? How
      many kilowatt-hours is this (divide previous answer by 1,000.)?
      If electricity costs 12 cents per kilowatt-hour, how much money
      does it cost to power this classroom for a full school day?

CONNECTIONS TO OTHER SUBJECTS (e.g. math, literacy, etc.):
    Math, technology

     1. Have students do an energy audit at home to determine how
        much carbon dioxide their family is releasing into the
        atmosphere and design a plan for reducing their family’s
        carbon footprint. Allow students to use the watt meters.
     2. Have the students do a case study of their school’s energy
        use and suggest changes for improvement.

clip: Green Ninja “Footprint Renovations”; chart showing average
power consumption of electrical appliances (one per group); Kill A Watt
electricity usage monitor (one per group- optional); calculator (optional)

If you do not have access to a watt meter, you can find charts showing average
power consumption from various electrical appliances at:


Adapted from:

Watt Meter Video:

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