The Law of Conservation of Energy says:

In physics, the law of conservation of energy states that the total energy of an isolated system remains constant—it is said to be conserved over time. Energy can neither be created nor destroyed; rather, it transforms from one form to another.

As a teacher this idea has so much that can be done with it, it starts with a class physics demonstration.

So there lots of ways you can go with this one. The same principle in the video applies to some games found at carnivals, fairs, and amusement parks known as Roller Bowler and Swinger. These games like many, are almost impossible to beat. Its not lack of skills, its trying to beat scientific laws.

Step 1: Swinger

A wooden pin sits on a table. Above it hangs a ball suspended from a rope. The object of the game is to swing the ball past the pin and knock it over as it returns towards you.

Step 2: Roller Bowler

The challenging game Roller Bowler is played by trying to roll the ball with just enough force so that it goes over the hump and stays in the pocket area on the other side. Just when it looks it is going to stay in the pocket area the ball comes rolling back.

Step 3: Building the Swinger Game





Table top

Find a way to attach to string to the ball and then mount it above. Depending how you mount the string and type of string used you do offer the potential to have the ball spin and add another variable making the game easier to win. But for the most part the its pretty negligible. You will want to adjust the string to appropriate height so the ball rest just over your table.

I had some light weight bowling balls and Pin that worked well courtesy of the Physical Education teachers.

Step 4: Roller Bowler Game

For this game I had to scale it down. For starters the bowling ball used in most game is way to expensive, let alone to work to bend and weld the metal your own Roller Bowler game.

So I decide it to scale it down.

You could use a billiards ball, but I decide to go smaller. I wanted my students to be able to create their own little version at a minimal cost.


Large Marble

3 feet of metal shelf strips


Wood board

The key to the game is to make the initial distance long enough that one can exert to much force on the marble causing the marble to eventually come back.

I think about 18 inches is good because it leaves you will enough slack to make a hill and a catch hill at the end.

Depending on how much metal you have to work with yours could vary. 18 Inches seems to work well in terms of proportion of the original game. The hill basically needs to have a slope of somewhere between 1/3 and 1/6.

Next you will want to bend the metal to create a small hill. This is tricky as you do not want to bend the metal to drastically that the marble will catch. It needs a smooth transition. The initial hill size can vary but the second hill definitely will need to larger than the first hill. I was much more successful with a smaller first hill and flatter pitch on to return the ball. It seems you pick up more friction with this design than the standard bowling ball.

Definitely a trial and error process to make this as easy or challenging as you like. I recommend two people here on the hold the metal rail and one play the game consistently. I found bending the ball on a basketball allow me to use the seams as landmarks and gave me some not subtle bends.

A few screws to hold the shelf in place and you a small scale Roller Bowler game!

<p>The pendulum demonstration is misleading. The theatrical professor gave the impression that the tremendous kinetic energy that the bowling ball achieves at the bottom of its arc would be just millimeters from impinging on his chin. But at the top of its arc, the velocity of the bowling ball is ZERO. That's ZERO kinetic energy. Even if he accidentally gave the bowling ball a small initial velocity, the kinetic energy his chin would have to absorb would also be small.</p>
<p>Correct. But it was fun to watch. And probably unforgettable. Unlike most of the physics education in school we got (admittedly I had a very good teacher for a while, but that was an exception).</p>

About This Instructable




Bio: I am a middle school math teacher in North Central Indiana. I have taught for the past 11 years. In addition to teaching middle school ... More »
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