Note: This video is designed to help the teacher better understand the lesson and is NOT intended to be shown to students. It includes observations and conclusions that students are meant to make on ...

It is tempting to think that some materials are always heavier than other materials. For example, someone might say that metal is heavier than air. But it depends on how much of each material there is ...

But what does that mean? The simple answer is how heavy something is for its size. If something seems very heavy for its size (like a heavy metal object), we say it is more dense. If something seems ...