## Friday, April 26, 2013

### mini Pulley

materials:
string
2 cups
pencil
tape

Kids construct a miniature pulley and discover how wheels can help reduce friction! Students keep one cup on the ground and have the other cup suspended in the air (both attached to the pulley). They place 20 pennies in the cup on the ground. Then, they place a few pennies at a time into the other cup. How many pennies are needed to raise the cup off the ground?

Then, they remove the thread spool. They place the string connecting the cups over the pencil. They do the same experiment above (20 pennies to one cup and add a few at a time to the other). How many pennies are needed to lift the cup off the ground?

Kids "compare the number of pennies needed to raise the cup with and without the rotating spool." Visit Education.com for more details (experiment called SHOWTIME from Janice VanCleave's book Machines for kids)!

Construction:
tape two 6 inch pieces of string to a table
insert a pencil into an empty thread spool
attach the pencil to the hanging string
cut a long piece of string (depends on height of table) and attach to both cups