Homemade Pulleys

Saturday October 17, 2009
These homemade pulleys work great as long as they glide freely over the coat hanger wire (meaning that if you give them a spin, they keep spinning for a few more seconds).  You can adjust the amount of friction in the pulley by adjusting the where the metal wire bends after it emerges from the pulley.

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Return-Mechanism Pulley System

Saturday October 17, 2009
Silly as our application for this experiment may sound, we use this system to keep pens handy near the shopping list on the fridge.  It’s saved us from many pen-searches over the years!

We install these at various places around the house (by the telephone, fridge, front door, anywhere that you usually need a pen at the last minute), and have even seen them at the counters of local video-rental stores.

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Block & Tackle

Saturday October 17, 2009
Simple machines make our lives easier. They make it easier to lift, move and build things. Chances are that you use simple machines more than you think. If you have ever screwed in a light bulb, put the lid on a jam jar, put keys on a keychain, pierced food with a fork, walked up a ramp, or propped open a door, you've made good use of simple machines. A block and tackle setup is also a simple machine.

Block and tackle refers to pulleys and rope (in that order). One kid can drag ten adults across the room with this simple setup – we've done this class lots of times with kids and parents, and it really works! Be careful with this experiment - you'll want to keep your fingers away from the rope and don't pull too hard (kids really get carried away with this one!)

If you haven't already, make sure you try out the broomstick version of this activity first.

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Pull Two Friends with One Hand

Saturday October 17, 2009
We're going to be using pulleys to pull two (or more) kids with one hand. You will be using something called ‘Mechanical Advantage’, which is like using your brains instead of brute strength. When you thread the rope around the broom handles, you use 'mechanical advantage' to leverage your strength and pull more than you normally could handle.

How can you possibly pull with more strength than you have? Easy - you trade ‘force’ for ‘distance’ - you can pull ten people with one hand, but you have to pull ten feet of rope for every one foot they travel.

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Simple Pulley Experiments

Saturday October 17, 2009
Are you curious about pulleys? This set of experiments will give you a good taste of what pulleys are, how to thread them up, and how you can use them to lift heavy things.

We'll also learn how to take data with our setup and set the stage for doing the ultra-cool Pulley Lift experiments.

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