Simple Machines, Part II

This week at Catalina we'll be exploring another Simple Machine! This time we'll test the effectiveness of an inclined plane (one of 6 simple machines) using marbles and tracks. This is an old favorite with my older students, as you may have seen in a previous post about Rube Goldberg machines. For preschoolers, a very simple 5-minute introduction to slope and velocity (i.e. how fast the marble goes) is enough to get them started building their own marble tracks. You'll be surprised at how adept they are at making these.

There is no shortage of materials you can use to build your own marble tracks. Here are some materials you may find at home:

• hotwheels tracks (these make excellent tracks for any age and are easy to put together)
• PVC pipe, any diameter or length
• outer casing of fluorescent light bulb tubes (I found someone at Ace Hardware who dug some up for me, as they're not usually sold on the shelf)
• wood cove moulding (found at home improvement stores, about $0.70 per linear foot for standard pine)
• cardboard boxes, building blocks, foam blocks, or cardboard bricks (for propping up the track and creating different slope grades)

If you use wood cove moulding, you can cut these to several different lengths to make it more interesting. Glue two equal-length sides together, side by side, to make a nice concave track for the marble, and that will also sit flat on the bottom. I used regular Elmer's "Glue All" to glue the pieces together and then clamped them together while they dried.

Try these out and have fun!