Friday, July 11, 2008

Make your own balance toy

I have came across an interesting wooden balance toy, usually found in the markets of Vietnam and Thailand. Unfortunately, I lost mine and this is the only similiar picture I can find online:

However, you could make your own balance toy by simply using a piece of cardboard!

Step 1 - Download the picture (click on it and download the full size).

Step 2 - Print the shape on a piece of carboard and cut out the shape.

Step 3 - Bend at the lines to create this:

There you have it! Now watch as it does a seemingly impossible act by balancing on the tip of a pen.

Questions to ponder:

  1. Is the toy considered stable?

  2. Where do you think is the CG of the toy?

  3. Do you think the toy is able to balance if you do not let the 'wings' droop down?

Ans: (highlight the space below with your cursor)

  1. Yes, because the toy returns to its original position after being tilted.

  2. The C.G. is below the tip (pivot), along the line of gravity pull.

  3. No. This is because moving the wings upwards will cause the C.G. to move upwards, resulting in an unstable equilibrium. I.e. the moments created by the weight of the toy when the C.G. is above the pivot will tend to topple it. When the C.G. is below the pivot, the moments created by the weight will tend to move the toy back to the original position.

Wednesday, July 2, 2008

My posting

I realise I haven't update that I've been posted to Kranji Secondary school. You can find out more from their website: A beginning teacher is a very busy person...

Sorry Shuqunites, I did request to go back but I guess Shuqun do not lack Physics teacher. Still, all the best for your 'O's! If you need help just let me know.