Simple Machines

We read the book The Very Last First Time for co-op last week.  In the book, the girl uses a stick to pry up mussels from the sea floor.  This is a simple machine called a lever.  I had Alex study simple machines.  He learned the difference between a simple machine (one that uses human effort to work) and a complex machine (one that uses artificial power to work.)  After he read about the simple machine and understood it, I had him look in a book that lists experiments for each.  He was to do the experiment with Nicolas in order to explain the concept to him.  He learned about the following simple machines and examples of each, along with the experiment that went along with it.

inclined plane (a ramp or a slide)

A raw egg dropped from the height of the can onto the plate broke.  (Actually it fell to the floor and broke on my rug, so we had to do a little laundry.)  But an egg rolled down an inclined plane from the same height did not break because there is less force.

a lever (shovel or a see saw)

The stool with Nicolas on it was hard to lift by hand, but when using a broomstick and chair as the fulcrum point, it was easier to lift.  This is because he was using his weight to push down in order to lift the stool rather than using his strength against gravity to lift the stool on his own power.

pulleys (on a crane)

We made our own pulley using an empty spool of thread and ribbon.  The pulley reverses the effort so that we need to pull down on the ribbon to lift up the bucket.

wedges (an axe or a nail)

For wedges, the boys cut wedges out of carrots and stuck them into an apple.  They discovered that it is easier to push carrots in when they have the point at the end than when the edges of the carrots are rounded.

screws (self explanatory)
wheels and axles (also self explanatory)

We did not do experiments for these two types because they are so common.

Here is the lapbook he created:

Characteristics of a simple machine.

This is a machine Alex invented that uses several simple machines - the lever to move the axes, wheels and axles to move from tree to tree and in the steering wheel and wedges to cut down trees.