How can a map of the seafloor be generated using mechanical waves?

The reaction q+r2=r2q is found to be first order in r2 and

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.

Light waves can move through , but they travel fastest when they move through a(n) .