fun with simple machines! wheels at work by bernie zubrowski and roy doty

My third grader is at home for a school holiday, and we decided to do a project together from this book, Wheels at Work.  We found this at our local library, and it has some really interesting yet doable science projects centered around building simple machines.  We chose the pulley project.  

If you would like to have fun with pulleys right along with us, here is the way to set up the experiment.  We used a 2x4 board that we had laying around and positioned it across the backs of two dining chairs.  We went to the hardware store and bought clothesline pulleys in several different sizes along with rope.  Make sure that the rope is the right size for fitting into the pulley grooves. You will also need a weight of some kind for the pulley to pull up and down.  The book suggests filling a milk carton with sand.  It was trash day, and all of our milk jugs had already gone out with the recycling.  We used a small beach bucket instead.  Yes that means that the sand can and will spill out.  See below.  I just vacuumed it up later. 

The book has several different set ups for the pulley so that we could see not only the many ways a pulley can work but also which set ups were more efficient at pulling the weight.  Here are the different ways to set up the pulley. 

While we constructed each pulley, we talked about force and how pulleys help us lift heavy objects.  When we lift a bucket of sand on with our hands, the hand is providing all of the force to lift the bucket.  When we employ pulleys, lifting is easier because the force is divided among the hand, the pulley, and the board.  My kiddo really enjoyed this simple project, and once he got the hang of how the pulley worked, he was inspired to try to think up his own arrangements and see if they worked.  I liked the project because it was relatively easy to set up, the book instructions were simple and clear, and the material was age-appropriate enough that he could do the project with a small amount of help from me.  I love projects where he can really take the reigns and feel confident.  Try it out! recommended age: 8-12