Paragraph: (Science-textbook/science-g3-12.txt)
Sent 1: You know that friction also causes heat.
Sent 2: Think about when you rub your hands together.
Sent 3: It is friction that makes them warm.
Sent 4: But why does this happen?
Sent 5: Friction causes the molecules on rubbing surfaces to move faster.
Sent 6: Faster moving particles have more heat energy.
Sent 7: Heat from friction can be useful.
Sent 8: Can you think of other places where you might find friction?
Sent 9: Friction also lets you light a match.
Sent 10: Heat from friction can also cause problems.
Sent 11: It can cause a car to overheat.
Sent 12: To reduce friction, oil is added to the engine.
Sent 13: Oil coats the surfaces of moving parts.
Sent 14: This coating of oil makes them slippery.
Sent 15: When things are slippery there is less friction.
Sent 16: Have you ever seen a sign that says, slippery when wet?
Sent 17: This too has to do with friction.
Sent 18: Water, like oil, can reduce friction.
Sent 19: The wet surface may allow your shoes to slide more easily.

Question: What would happen if all the oil leaked out of a running car engine? (true/0)

Question: What problem can friction cause? (false/1)

Question: Why do rubbing your hands make them warm? (true/2)

Due to friction
Friction
Friction causes molecules on the surface to move faster and faster molecules have more heat energy
Mass
From chemical reaction
Because of friction making the particles move faster
From electric current
From mechanical reaction
Moving hands

Question: How does oil reduce friction between moving car parts? (false/3)

Question: Do particles rubbed against a slippery surface move faster or slower? (true/4)

Moving
Faster
Slower

Question: What can happen in a car when there is too much friction? (false/5)

Question: What is friction? (true/6)

A chemical reaction
Friction causes the molecules on rubbing surfaces to move faster
Friction causes molecules to move faster in order to create heat energy
Friction causes the molecules on rubbing surfaces to move faster. Faster moving particles have more heat energy
The exchange of molecules
Friction destroys molecules
The force that holds things to earth

Question: Why do your hands become warmer when you rub them together? (false/7)

Due to friction
Because of friction
The friction produced by rubbing them together causes molecules to move faster, and faster moving molecules have more heat energy
From chemical reaction
From electric current
Because of friction making the molecules move faster
Because of mass
From mechanical reaction
Moving hands

Question: What can be done to prevent friction problems in engines? (true/8)

Question: Can oil reduce the amount of heat that is produced from the moving parts of a car? (true/9)

Yes
Sometimes
Can cause overheat

Question: What happens when you rub your hands together? (true/10)

Question: If you try to warm your hands by rubbing them together when they are wet, will they warm up as well as rubbing them together when they're dry? (true/11)

No
Sometimes

Question: Are you likely to experience more friction walking on a surface covered in oil or water than on a dry surface? (true/12)

Surface covered in oil or water
Dry surface
Oil friction