Lesson 12 Reading One— How Can the _________________ of a Balloon Change without Removing or Adding Air?

• Mass

• Volume

• Density

• Pressure

Popcorn pops because each kernel contains water. As you

heat popcorn, the water molecules inside each kernel move ____________________.

• slower

• faster

• smoother

• more slowly

The reasons that a popcorn kernel pops are the same reasons that a balloon shrinks and expands as the molecules inside of it are heated and ___________________.

• warmed up

• cooled

• slowly warming

• respected

What happens inside a balloon and what happens inside a popcorn kernel can both be explained by knowing the behavior of ______________________.

• parts

• skills

• particles

• bikes

Longer arrows mean the particles are moving _________________. Shorter arrows mean they are moving more slowly.

• slower

• faster

A balloon can stretch if something pushes against it. As the

gas particles push the balloon, they make the ______________ stretch, and it gets larger.

• bike

• bat

• balloon

• ball

As more gas is added to a balloon, the pressure against the sides of the balloon increases. The gas particles move further apart and push against the sides of the ___________.

• ball

• balloon

• button

• bike

If you put more gas into a balloon than it

can stretch to hold, the balloon will ________________.

• get smaller

• hum

• sing

• break

If you tie a balloon shut and then put it in ice, the particles slow down. They do not have as much __________________.

• sun

• power

• joules

• energy

Molecules spread all over the space inside the balloon, not just in the center or in any other spot.

• true

• false