Dear Mythbusters. I hope you know that I think you are awesome. I know you are not scientists, but rather master robot builders. I respect that. I envy your robot-building abilities. Please forgive me for pointing this out – but even if a tree is 90% air, that does not mean a ball has a 90% probability of passing through it.

For those of you who are unaware, in the last episode of MythBusters, they explored the idea that a golf ball should pass through a tree 90% of the time. What if they were to test following alternative myth:

*A golf ball has a 90% chance of passing through something that is 90% air.*

Here is my test object:


It is a steel box with air inside. I did not give the dimensions, but you can imagine it would not be difficult to make this 10% steel and 90% air. What would happen if I hit a golf ball at this? I think there were would be a 0.000000000000000000001% percent chance of it going through (smaller than that – but I think you get the idea).

What is really important is the scattering cross-section, not the density.