Wheels and Rollers
What is the difference between a wheel and axle and a roller?
A wheel is attached to an object but a roller is not. Rollers are usually longer.
What is a lever?
A simple machine with a long board or rod that rotates on a fulcrum
What is a gear?
A circular simple machine that has teeth (cogs) that can be spun and attached to other gears
What type of lever is a pair of scissors?
Why are machines important?
They make work easier
When would you choose to use a roller instead of a wheel and axle?
When the distance a load needs to move is always the same
Why do we use levers?
They make it easier to lift objects
What is a drive system?
The combination of parts to make things move
Give an example of a roller
A grocery store conveyor belt
What type of simple machine can help us to lift a heavy load?
A pulley or a lever
When would you choose to use a wheel and axle instead of a roller?
You would choose to use a wheel and axle when the distance changes and when the load can have wheels attached. Or you can use a wheel to make something like a cart to carry a load.
How can we remember the difference between the three classes of levers?
FLE 123
What is the first gear in a drive system called?
The driver
What type of lever is a pair of tongs?
Class three (the effort is in the middle)
What is an example of a lever found in this classroom?
Scissors, stapler, hole-punch, etc.
What problems might you run into when using rollers?
They are not attached to the object, so eventually the load will reach the end of the rollers/fall off the rollers
How could you adjust your lever if the object you were trying to lift was too heavy?
You could move the fulcrum closer to the object you are lifting
What is the difference between a drive system that uses wheel-to-wheel contact and a drive system that uses a belt, elastic, or chain?
In wheel-to-wheel contact, one wheel causes another wheel to turn by rolling against it. In a belt or elastic drive system, a belt or elastic is attached to one wheel, causing another to turn (the wheels or gears don’t touch).
In wheel-to-wheel contact, the wheels turn in opposite directions, when using a belt or elastic they turn in the same direction.
What type of drive system is a bicycle (wheel-to-wheel contact, belt/elastic, a chain, or gears)
a chain
If the driver is smaller than the second gear, what will happen to the speed and force of the second gear?
The second gear turns slower but with more force
What force to wheels and rollers help against?
Friction
How could you adjust your lever if you needed to lift an object higher?
You could move the fulcrum closer to where you are applied effort (further from the load)
If the driver is bigger than the second gear, what will happen to the speed and force of the second gear?
The second gear will turn faster but with less force
What type of lever is a wheelbarrow?
Second class (the load is in the middle0
Which takes less effort to turn: parallel gears (when gears are beside each other) or intersecting gears (when one gear is at a 90-degree angle to the other)?
Intersecting gears (90-degree angle)