Welcome 5Welcome 5thth & 6 & 6thth grade grade students at St. Mary’sstudents at St. Mary’s
We are going to be learning We are going to be learning about simple machines. We about simple machines. We will learn what a simple will learn what a simple machine is, how we use them, machine is, how we use them, and why we use them.and why we use them.
Welcome to a world full of Welcome to a world full of machines!machines!
There are machines all around There are machines all around us!us!
Turn to your neighbor and Turn to your neighbor and discuss what kinds of discuss what kinds of machines you saw on your machines you saw on your way to school today.way to school today.
The 6 Simple MachinesThe 6 Simple Machines
All machines are made up of some of All machines are made up of some of the 6 simple machines. They are:the 6 simple machines. They are:
Wheel and axleWheel and axle PulleyPulley LeverLever WedgeWedge ScrewScrew Inclined PlaneInclined Plane
Why do we need simple Why do we need simple machines?machines?
Work means that we are exerting Work means that we are exerting force and moving something. The force and moving something. The 6 simple machines make our work 6 simple machines make our work easier. We won’t have to use as easier. We won’t have to use as much force with our simple much force with our simple machines.machines.
The Wheel and AxleThe Wheel and Axle
Two or more wheels Two or more wheels are connected by an are connected by an axle. axle.
The wheel turns with The wheel turns with or around the axle.or around the axle.
This car wheel has a This car wheel has a big axle that it big axle that it rotates around when rotates around when the car moves. the car moves.
Why do we need wheels?Why do we need wheels?
Wheels help us move heavy objects. Wheels help us move heavy objects. They roll easily.They roll easily. Did you know a doorknob is really Did you know a doorknob is really
two wheels connected by an axle? two wheels connected by an axle? You can’t see the axle because it’s You can’t see the axle because it’s inside the wheels, but it’s there! inside the wheels, but it’s there!
If there wasn’t an axle, the doorknob If there wasn’t an axle, the doorknob wouldn’t turn!wouldn’t turn!
Another kind of wheel is Another kind of wheel is called a gear!called a gear!
A gear is a wheel with teeth. A gear is a wheel with teeth. The teeth fit in between each other The teeth fit in between each other
and turn. and turn. When one gear turns, its teeth push When one gear turns, its teeth push
against the teeth of the other gear against the teeth of the other gear and they both turn. and they both turn.
There are gears on your bike, on a There are gears on your bike, on a can opener and on an egg beater.can opener and on an egg beater.
Pulleys Pulleys
Lifting a bucket full of water Lifting a bucket full of water is a lot of work!is a lot of work!
A pulley is a wheel with a A pulley is a wheel with a rope running over it. The rope running over it. The wheel has a groove, called a wheel has a groove, called a sheave, and it keeps the sheave, and it keeps the rope from slipping off the rope from slipping off the wheel. wheel.
Remember, since there is a Remember, since there is a wheel in a pulley there also wheel in a pulley there also has to be an axle!has to be an axle!
These two men are using a These two men are using a pulley to help them lift their pulley to help them lift their
heavy bucket.heavy bucket.
LeversLevers
There are three There are three parts to a lever:parts to a lever:
Load Load ForceForce Fulcrum: support Fulcrum: support
or balanceor balance
A seesaw is a leverA seesaw is a lever
Let’s pretend you are Let’s pretend you are riding a seesaw with riding a seesaw with your friend. your friend.
The center support is The center support is the fulcrum, which does the fulcrum, which does not move. not move.
The load is your friend The load is your friend sitting on one end.sitting on one end.
You exert the force at You exert the force at the other end trying to the other end trying to lift your friend off the lift your friend off the ground. ground.
When you push down on When you push down on your seat, (the force) you your seat, (the force) you can lift your friend (the can lift your friend (the load) while the fulcrum load) while the fulcrum acts as the pivot point, acts as the pivot point, making the seesaw go up making the seesaw go up and down. and down.
It’s easy to lift your It’s easy to lift your friend this way instead of friend this way instead of just picking her or him up just picking her or him up by yourself!by yourself!
The Wedge The Wedge
A wedge is used to A wedge is used to split, tighten, or secure split, tighten, or secure a hold. a hold.
A wedge is usually a A wedge is usually a triangle shape with a triangle shape with a sharp point. sharp point.
If you apply force at If you apply force at one end, the wedge one end, the wedge will go between will go between something, in this case something, in this case an ax splits a piece of an ax splits a piece of wood.wood.
Where can we find Where can we find wedges?wedges?
Wedges that split:Wedges that split: Your teeth!Your teeth! Every time you bite Every time you bite
into something, you into something, you are using a wedge.are using a wedge.
Wedges that cut:Wedges that cut: A saw!A saw! A knife!A knife!
Wedges that Wedges that tighten:tighten:
A doorstop to keep A doorstop to keep the door open.the door open.
Wedges that hold Wedges that hold things together:things together:
A nail holds wood A nail holds wood to a wall or other to a wall or other wood.wood.
The ScrewThe Screw
The three parts to a screw:The three parts to a screw: HeadHead ShaftShaft TipTip The head is the part that The head is the part that
you exert a force on.you exert a force on. The shaft has ridges, The shaft has ridges,
called threads that wind called threads that wind around the screw. If it around the screw. If it doesn’t have the threads, doesn’t have the threads, it is probably just a nail.it is probably just a nail.
The tip is sharp.The tip is sharp.
How to use a screw:How to use a screw:
Fasten two things togetherFasten two things together When you turn it, the threads cut a When you turn it, the threads cut a
groove in the material, making a groove in the material, making a hole. The groove holds the screw hole. The groove holds the screw tightly in place. tightly in place.
To remove the screw you turn it To remove the screw you turn it the opposite way, you can’t just the opposite way, you can’t just pull it out. pull it out.
The Inclined PlaneThe Inclined Plane
It is a slanted surface It is a slanted surface or ramp. or ramp.
It makes moving It makes moving objects easier. objects easier.
Roads are also Roads are also inclined planes. inclined planes. Instead of going Instead of going straight up, like this: straight up, like this: roads go up at small roads go up at small angles, like the angles, like the picture.picture.
The 6 Simple MachinesThe 6 Simple Machines
Lever Pulley
Wheel and Axle
WedgeScrew
Inclined Plane
You have finished the slide You have finished the slide showshow
Be sure you have completed all of the questions on your
worksheet.
We will be going over this as a class.
