The Particle Model · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Squashing Gases and Floating Ice

Science · Matter & Materials · ages 11-12
Name ______________________   Date ____________

  1. Why can a gas be squeezed into a smaller space?

    • Its particles shrink when pushed
    • Its particles have empty space to move in
    • Its particles turn into liquid when pushed

  2. In a gas, how are the particles arranged compared to a solid?

    • Spread far apart with gaps between them
    • Packed tightly together in a fixed pattern
    • Arranged in neat rows that never move

  3. Ice is denser than the liquid water it floats on.

    Circle one:   True   False

  4. A gas and a solid fill boxes of the same size. Which has fewer particles inside, and why?

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    • The gas, because its particles are spread far apart
    • The solid, because its particles are spread far apart
    • Both boxes hold the same number of particles

  5. Priya pushes the plunger on a sealed syringe full of air. It moves in easily. Why?

    • The air particles get smaller when pushed
    • The air leaks out through the syringe wall
    • The air particles are spread out, so there is space to push them closer together

  6. The same mass of a metal is compared as a solid block and as a gas. Which is true?

    • The gas takes up less space than the solid
    • The gas takes up far more space, so it is much less dense
    • They take up exactly the same space

  7. Leo says, "Ice floats because it is warmer than the water around it." Is Leo's reasoning correct?

    Circle one:   True   False

  8. Tom squashes a balloon full of air and it easily gets smaller. He tries to squash a plastic bottle completely full of water, and it will not squash at all. What explains the difference?

    • Air particles are magnetic, but water particles are not
    • Water is too heavy to squash, but air is light enough to squash
    • Air particles are far apart and can be pushed closer, but water particles are already touching with no room to move
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Squashing Gases and Floating Ice W1-mt_b6kZgqolEd-s1

  1. Its particles have empty space to move in · There's empty space between gas particles, so pushing them closer together is easy.
  2. Spread far apart with gaps between them · Gas particles have lots of empty space between them, unlike the tightly packed particles in a solid.
  3. False · Ice is actually less dense than liquid water. That's the only reason it floats instead of sinking.
  4. The gas, because its particles are spread far apart · Gas particles spread out, so far fewer of them fit in the same space compared to a solid.
  5. The air particles are spread out, so there is space to push them closer together · Gas particles start out far apart, so pushing the plunger just closes up the empty space between them.
  6. The gas takes up far more space, so it is much less dense · Spread-out gas particles mean the same mass of gas fills a much bigger space, so gases are far less dense than solids.
  7. False · Temperature is not the reason. Ice floats because its particles lock into a pattern with more space between them, making ice less dense than liquid water.
  8. Air particles are far apart and can be pushed closer, but water particles are already touching with no room to move · There is empty space between air particles to push into. Water particles are already packed together, so there's nowhere for them to go.
Worksheet · LightMySky