Thermal Energy

What happens to the molecules of a solid when it is heated?

• Slow down
• Speed up
• Don't change speed
• Shrink

The liquid in a thermometer ______________ as the temperature increases.

• expands
• disappears
• freezes
• explodes

Many objects, such as train tracks and road joints, are specifically designed to allow extra space for ...

• thermal energy
• specific heat
• thermal expansion
• conductors

The picture shows a bimetallic strip in a fire alarm. When there is a fire outbreak, the bimetallic strip will get hot, ....

• bend downwards, complete the circuit and the alarm rings.

• bend upwards, open the circuit and the alarm will not ring.

• becomes longer, open the circuit and the alarm will not ring.

Water always expands as it's heated.

• True

• False

When objects contract upon cooling...

• volume increases and density increases.
• volume increases and density decreases.
• volume decreases and density decreases.
• volume decreases and density increases.

Alex noticed that a metal door that sticks on hot days does not stick when it cools off at night. This is because the metal contracts as it cools. The reason for this is that, as the metal cools, the atoms:

• become smaller and take up less space
•  slow down and move closer together
• merge together to form fewer atoms
• speed up and move farther apart

What would happen to the pressure of a gas which is heated at constant volume?

• Its pressure would remain same

• Its pressure would increase

• Its pressure would decrease

A bimetallic strip is made up of _____________________ welded together.

• two metals of the same kind 
• two different metals that expand and contract unequally
• two different metals that expand and contract equally

When atoms vibrate more, they

• become further apart

• become closer together

• not changing distance