Summary
If ice is made of water, how come it floats? How can a single substance be liquid, solid, or gas anyway? To answer these and many other riddles of nature, you have to know about density, a fundamental property of all matter. You can figure out the density of any substance by calculating the ratio of its mass to its volume. Atoms give matter its mass, and their arrangement determines the matter’s volume. Changes in their arrangement affect the substance’s density—and can turn solids into liquids, or liquids into gases. Density can help you solve everyday mysteries, too, like figuring out what an object is made of. But there’s a catch: What if an object’s shape makes it too complicated to calculate its volume? Fear not, there is a way to do that. Press “play” to see for yourself!
Viewer safety
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Teaching resources
Discussion questions
A few questions to talk through after watching Density:
- What is one new thing you learned about density?
- Can you explain it to a partner in your own words?
- Where might you see this in the real world?
- What is one question you still have?
Quick work-a-long
Try it:
- Write one sentence explaining density.
- Draw or give one example of your own.