What is mass?
when one surface or object rubs against another
the force that attracts things towards Earth
the amount of matter in something
pushes and pulls
What is a force?
the amount of matter in something
the amount of matter in something
when one surface or object rubs against another
pushes and pulls that change the motion of objects
Why does rubbing your hands together warm them up?
friction!
What would happen if friction didn't exist.
We would all be slipping and sliding.
Give me two examples of friction in action!
.
Friction happens because most surfaces are completely smooth. True or false?
False! Most surfaces are not completely smooth. You just need a microscope to see it.
How does friction cause heat?
When surfaces get rubbed together, the molecules start moving faster. This movement causes the material to get hotter.
What is a friction burn?
Burns caused by friction working at high speeds.
True or False. Water has a skin that allows insects to stand on the water.
False! Water doesn't have skin. It has surface tension.
Can water surface tension support our weight?
No! It can only support a little bit of weight.
Is your weight the same in every planet of our Solar System? How about your mass?
Your weight is different, because it depends on the gravity. Your mass is the same!
How does a parachute work? Why do people wear them when they go parachuting?
When the parachute opens, the air resistance is greater than the gravity. This slows the person down and allows them to land safely.
How do we know if an object will sink or float in water?
to float, an object has to be less dense than water.
