Simple Machines: Let’s Make a Pulley

Today we are doing some fun hands on activities exploring simple machines. Simple machines are tools that make our work easier by letting us push or pull things with less effort. They help us lift, move, or secure objects more easily by changing the direction or the amount of force we need to apply. When put into action, a simple machine looks more like play than work!

What is a Simple Machine?

A simple machine is a device that has a mechanism that can be used as a building block for more complicated machine. There are six types of simple machines. Each of these simple machines are things that we can build at home to lessen our “work” load:

• lever (like a seesaw)
• wheel and axle (like a doorknob)
• inclined plane (like a ramp)
• wedge (like a doorstop)
• screw (like a jar lid)
• pulley (like a flagpole)

Today we are going to concentrate on one of these simple machines: the pulley. By building a pulley together we can see all sorts of ways that pulleys can be used to help people lessen the load.  

Supplies Needed to Build a Pulley

• string or rope
• rolling pin
• something to lift* (a bucket works great)

*Instead of a bucket, we lifted the VERY heavy English book.  

How to Build a Simple Pulley with Kids

Step 1

Start by tying your string or rope onto the item you are going to lift. If you are using a bucket or something that has a handle, then tie it onto the handle. If you are using something like we did, a book, then first tie the book across each side (like you would a package) and then attach the rope or string onto the mid point of the book in the middle.

Step 2

Have the child lift the item using the string/rope without the pulley and assess how easy or hard it is to move upward.

Step 3

THEN loop the string OVER the rolling pin and tried to lift the book again using the end of the rope/string.

Science Behind Pulleys

A pulley is a wheel on an axle that is designed to support movement of a cable or belt along its circumference. – Oxford English Dictionary

Pulleys can be used to lift weight.  In the simplest terms, a pulley works because the portions of rope on either side are supporting 1/2 the weight. There are ways to cut this load even more by combining fixed pulleys, making the pulley movable, or combining fixed and movable pulleys into a compound pulley.

We weren’t too worried about the math implications of all this today, but exploring that could put numbers to something that they can experience.

Our Experience Making a Pulley

• Each boy expressed amazement at how much easier it was to lift the book with the pulley.
• They then took another 50 or so turns followed by a hunt through the house for things to practice lifting with and without our fancy pulley.
• The boys went through the house and garage looking for pulley machines at work.
• The most notable were the light fixture in our game room and a Lego pulley built into the boys’ Lego village, but the boys remembered a MUCH better pulley…

…the bucket pulley at Grandpa’s tree house.

More Science Fun for Kids from Kids ACtivities Blog

• Lift an ice cube with a string
• Gravity Experiment for Kids
• How to make a compass
• How to make a catapult
• Recycled Robot Craft
• Science fair ideas kids love
• Fun science experiments you can do at home
• Science games! <–need I say more?
• Air pressure experiment fun
• Our favorite preschool science activities
• Egg and vinegar experiment
• Build your own atom model
• Grab our fun scientific method worksheet for kids

Did you build a pulley? What did you lift? Tell us in the comments below!