Jimmy is cooking pasta in a pot of water on the stove. He uses a stopwatch to see how long the pasta takes to cook depending on the temperature of the water in the pot. What is the independent variable and why?

Which of the following correctly describes what happens when an atomic bomb explodes? small pieces of fissionable material are joined and form a body with a mass greater than the critical mass, the relative number of neutrons escaping decreases, and a chain reaction and explosion result. large pieces of fissionable matter are brought together quickly and form a body with a mass smaller than the critical mass, the relative number of escaping neutrons increases, and a chain reaction and explosion result.