Often a poor choice of words or a mis-use of words can leave an incorrect
impression in the minds of our students. In other words, sometimes through
our own carelessness, we “shoot ourselves in the foot!” Throughout this
course, we will make note of places where these might occur.
Nope! Heat causes molecules in the air to move more quickly and the air
becomes less dense. Being less dense, warm air rises.
Cold water is heavier than warm water, so it sinks.
Close, but be careful! Cold water is denser than warm water, so
it sinks. It is important that we differentiate between weight and density.
However, if you actually have the same volume of each, the cold water
will actually weigh slightly more, because there are more molecules per