Just to clarify the ice cube problem. If you had a glass full to the brim with ice and let it melt it would fill less space (i.e volume) Displacement refers to equal weight and not equal volume :wink:
If your said bus was travelling at the speed of light and the driver switched his headlamps on. Would they shine ahead of him so he could see where he was going?
Most of the buses around here barely get above 15mph before they start belching out black smoke but nice idea anyway :D :D :D :D