# Newton’s Tower

Yesterday, Travis and I marveled at some good oldĀ laws of physics and inertia, making pennies fall into a cup. We wanted a repeat of this magic today, so made this tower named in honor of Isaac Newton and his first law of motion: that an object will stay at rest unless acted upon by an external force.

The idea here is to hit only the bottom box in a tower of boxes. The bottom box is moved by an external force, but not so the others. So what would happen to these higher boxes?

You’ll want to use small boxes for this experiment. I had some old gift boxes that were probably about as big as you want to go; smaller would be even better.

To make them pretty, I wrapped each in a separate shade of construction paper.

To start, Travis and I tested if we could make the experiment work only three levels high. Zoom! The orange got whacked away with a dowel, and the red and yellow stayed put.

Could we make it work with four? It worked perfectly – not the orange box off to the side, now.

Notice the orange off to the side there.

Needless to say, Travis loved a science experiment that involved whacking things with a stick. I taught him that the secret is to whack the bottom box as hard and as fast as you can. Finally, we challenged ourselves with all 5 boxes.

Boom!

# Motion Magic

You’ll stun your kids with the way a penny doesn’t move in these games, a fantastic illustration of inertia. You can give a quick physics lesson – basically, things that aren’t moving want to stay put – but whether they grasp the concept or not, they’ll be amazed by the results.

We tried out the motion magic in two ways. For the first, we cut a square of cardboard as a base (using a bit of our Kiwi Crate from the Disk Launchers set). Place the cardboard over a glass, and put a penny on top.

Quickly flick the cardboard away (from the side, not from underneath). The cardboard will fly away but the penny…

…falls in the glass! This got a whoa from Travis, who then tried himself and was so proud it worked.

There is something sort of magical about inertia, even for grown-ups. Logically we want that penny to fly away, and every time we heard the clink of the penny in the glass, we were excited.

For the second method, we cut a strip from cardstock. Form it into a circle and staple the edges.

Place the circle over the glass, with the penny on top.

Very quickly, put a finger inside the cardstock circle and flick it out of the glass. Where did our penny go?

Down inside!

Want to really up the wow factor? Try the classic trick of pulling a tablecloth out from under a plate (you might want to use a paper plate, just in case).

Is it magic? Nope, it’s inertia of course.