Heat and temperature
Touch a hot block to a cold one and watch heat flow from fast-jiggling particles to slow ones until both are the same.
Standards: MS-PS1-4MS-PS3-3
1Wonder
Leave a hot cup of cocoa on the table and it cools down. Leave a cold glass of juice and it warms up. Both end up at room temperature. What is actually moving, and why does it always go the same way?
2Explore
This activity needs a bigger screen
Turn your phone sideways, or open this lesson on a tablet or computer. The explanation and quiz below work here.
- Make the left block hot and the right block cold. Watch the particles. How do they move differently?
- Press Let them touch. Which way does the heat arrow point? When does it stop?
- Make the left block Big and try again. Is the final temperature still halfway?
- Turn on Put foam between them. What changes on the graph?
3Explain
Temperature is jiggling
Everything is made of particles that are always jiggling. In a hot object they jiggle fast; in a cold one, slowly. Temperature measures how fast the particles move, on average.
Temperature is how fast the particles jiggle. Heat is energy flowing from hotter to colder, until both are at the same temperature. Bigger objects hold more heat; insulators slow heat down, conductors let it through.
4Practice
Which way does heat flow on its own?
5Recap
- Temperature measures how fast particles jiggle.
- Heat flows from hot to cold until the temperatures are equal (thermal equilibrium).
- Big objects hold more heat energy than small ones at the same temperature.
- Conductors (metals) pass heat quickly; insulators (wood, foam, wool) slow it down.