Rollers and Wheels
Which was made first, wheels or rollers?
Rollers were made first.
What is a pulley?
A pulley is a wheel with a groove in the rim. A rope sits in the rim of the wheel- which we pull to apply force.
What are the spikes on a gear called?
Teeth or cogs.
What is a lever?
Is a simple machine that uses leverage to life easier.
They usually consist of a long flat board and a fulcrum.
A simple machine is a device that makes our lives easier or helps lift and move heavy loads.
Wheels and rollers work by reducing which force?
Friction!
When you pull down on a pulley, the load will move ____
up!
What is a gear?
A gear is a wheel with teeth that slot together, so that when one gear turns the other turns with it.
Explain what a class 1 lever is. What is an example of a class 1 lever?
Class 1 levers have the fulcrum in the middle and the load and effort are on either side.
ex. seesaw, light switch, scissors
Define- "Wheel and Axle"
It is a machine where a wheel is attached to an axle and when force is applied, they rotate together.
Who invented the rollers?
The Egyptians
What are some objects or things that use a pulley?
Flag poles, blinds, crane....
How do you make gears turn in the same direction?
What is an example of a class two lever?
A class two lever is where the load is in the middle.
ex. wheelbarrow, bottle opener, suitcase...
Define "fulcrum"
The is the supporting part of a lever.
What was a wheel first used for?
It was used for pottery!
How does a pulley help us lift heavy objects?
When you pull down on a pulley, the downward force makes an upward force.
The gear that changes the direction of a gear train is called the ___________?
Idler gear.
Where do we move the fulcrum to make a load lighter?
You could move the fulcrum closer to the object you are lifting.
Define- "force"
It is a push or pull that causes a direction or movement.
An _________ goes in the wheel to help the wheel move?
axle
What happens when you use more than one pulley to lift a heavy object?
It magnifies the force we are using/applying.
There are two gears- one is attached to the pedals and one is attached to the back wheel. When you pedal the larger gear on the pedal, the smaller gear on the wheel spins more times. This means the wheel rotates more than the pedal.
What happens when we move a fulcrum in a lever?
It creates a mechanical advantage by moving the fulcrum. It makes the force stronger.
Define- "friction"
Friction is the resistance that a surface or object and encounters when moving against something else.