An example of a grad-school level question?
Falling and rising air and water molecules inside of clouds are believed to be factors in the formation of lightning. Which kind of energy transfer is taking place to cause this weather phenomenon?

An example of a grad-school level question?
A student wraps a wire around an iron nail. The student then connects the wire to a battery. The nail attracts another nail and they stick together. What force holds the two nails together?

An example of a grad-school level question?
A group of scientists predicts that Earth's oceans will be able to take up more carbon dioxide as atmospheric carbon dioxide levels increase and the atmosphere warms. Which of these statements about the solubility of gases in ocean water would lead you to question this prediction?

An example of a grad-school level question?
Large populations of tortoises inhabited the Galapagos Islands before humans. When humans settled on the islands and introduced goats, the number of tortoise declined. What is most likely the explanation for the decrease in the tortoise population?