Diffusion

							Diffusion
 Write down the stuff in red
       What is Diffusion?
• Diffusion is the
  movement of
  particles from high
  concentration to
  low concentration.

• Think of a slippery
  slide – you always
  go from high to
  low.
        What is Diffusion?
Think about an
  elevator…

If there are 20 people
    crammed inside an
    elevator, what is
    the first thing they
    do when the doors
    open?
       What is Diffusion?
If we could use a
   magic microscope
   that would show
   diffusion on a
   molecular level…


                      Particles are HIGHLY
                       concentrated and
                      “squished” together
                           (Draw this)
       What is Diffusion?
If we could use a
   magic microscope
   that would show
   diffusion on a
   molecular level…


                       Particles spread out
                      and DIFFUSE into areas
                             of LOWER
                          concentration
                              (Draw this)
             Prove It #1
• Does diffusion happen
  in a gas?

• Put your head down
  and close your eyes.

• Raise your hand when
  the “smell particles”
  reach your nose.
                          HOW did the molecules
                                  move?
• Which way did the         Are there any fans
  molecules move?                 going?
    Draw a Conclusion
• Evidence:   • Inference:
              Prove It #2
• Does diffusion happen
  in a gas?

• Shine a flashlight in a
  darkened room.

• See any “alien
  spaceships” floating in
  the air?

• Are they falling
                            What is making the
  downward, or moving
  in all directions?         particles move?
    Draw a Conclusion
• Evidence:   • Inference:
Diffusion happens in a gas.
             Prove It #3
• Does diffusion happen
  in a liquid?

• Put a drop of food
  coloring into a clear
  container of water.

• Make some
  observations

• Which way did the       HOW did the molecules
  molecules move?                move?
    Draw a Conclusion
• Evidence:   • Inference:
           Prove It #4
• Does diffusion happen
  in a liquid?

• Put a few drops of
                          • Brownian Motion
  milk on a microscope
  slide.

• Look into the
  microscope and make
  some observations.
                            Was there anything
• What is happening?         mixing the milk?
    Draw a Conclusion
• Evidence:   • Inference:
Diffusion happens in a liquid.
            Prove It #5
• Does diffusion happen
  in a solid?

• Think of your prior
  experience…

• Have you ever seen
  solids rearrange by
  themselves?
    Draw a Conclusion
• Evidence:   • Inference:
Diffusion does not happen in a
            solid.