## Coin Landing On Its Edge

December 2, 2015 Leave a comment

I flip a fair Swiss franc* and it falls in mousse**. **What is the probability that the coin stays on its edge after the mousse melts? **

*One Swiss franc is about 1 USD; diameter 23.20mm , thickness 1.55mm, weight 4.4g. During a coin toss, the coin is thrown into the air such that it rotates edge-over-edge several times.

**A mousse (French ‘foam’) is a prepared food that incorporates air bubbles to give it a light and airy texture.

**Solution**

The probability that the coin stays on its edge is about 4% for a Swiss franc and 5% for an American dime.

http://www.aplusclick.com/t.htm?q=5135

Such an outcome on a hard and flat surface is fairly unlikely, having been estimated at approximately 1 in 6000 tosses.

https://en.wikipedia.org/wiki/Coin_flipping

https://www.seas.harvard.edu/softmat/downloads/2011-10.pdf