Simple Machines

Before Video

• Pushing a shopping cart at the grocery store or pushing your friend on the swing are some examples of pushing heavy things.

• You could have a friend help you or you could use ropes to help lift it. You can also use simple machines!

• Bikes, cars, shopping carts and strollers all have wheels.

• Pulling a door closed, pulling a tissue out of a tissue box or pulling on a dog leash are examples of pulling.

• Heavy things are harder to pull than lighter things. Examples of heavy things might be a big dog on a leash, pulling your friend in a wagon or pulling yourself up on the monkey bars.

• Lifting heavy things onto the shelf in a closet or picking up a stack of books from the floor and putting them on a tall desk are all examples.

After Video

• Simple machines have few or no moving parts. They make work easier by changing the direction of a force or by changing the amount of force needed.

• Simple machines can help make work easier. Without simple machines you might not be able to move something really heavy.

• A pulley uses a wheel to change the direction of a force. As you pull down, the object goes up. Sometimes pulling down is easier because the force of gravity helps.

• When you push down on one end of a lever, the other end moves up in the opposite direction, like a seesaw. By moving the middle part of it called the fulcrum close to the object you want to lift, it becomes easier to lift it. Elijah did this in the video to lift the rock.

• When the ground is not smooth, friction can make it difficult to move heavy things, which is what happens when things rub against each other. A wheel and axle reduce friction by allowing things to roll, which makes them rub against each other less.

• An axe is a wedge that can be used to split a piece of wood. A knife is a wedge you use every day. You can also use a wedge to hold open a door.

Tools that make difficult tasks easier by changing the direction of the force or the amount of force needed to do something.

A simple machine that has a gently sloped surface so it can be used to move objects upwards with less force. Ramps are examples of inclined planes.

An inclined plane wrapped around a center rod. An example of a screw is a spiral staircase.

A simple machine that gets thinner at one end that is used to split material such as wood. A knife is an example of a wedge.

A plank that rests on something underneath and moves up and down. A seesaw is a lever.

A wheel and rope that can change the direction of a force. A flagpole uses a pulley to raise the flag.

A simple machine used to move objects across a distance using a round part (wheel) and a long part (axle). Cars have wheels and axles.