# heat (thermal)

when energy moves into matter, the matter becomes hot

- Computed level: L20 (depth in the emergence graph, not abstraction)
- Status: review  ·  Domain: everyday  ·  Arena: everyday

## Emergence
**Emerges from:** [energy](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-energy.capacity), [matter](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-matter.substance), [become](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-become.change), [hot](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-hot.temperature)

**Through:** energy capacity moves into matter substance, causing a change that results in higher temperature.

**Novel properties:**
- increased thermal energy
- detectable temperature rise
- molecular motion increase

## Examples
- The Sun heats Earth's surface to an average of 15°C by radiating energy absorbed by land and oceans. *(astronomy)*
- A car engine reaches 90°C during operation as friction and combustion transfer energy to metal parts. *(engineering)*
- Lava in Kīlauea volcano rose to 1,200°C after magma transferred thermal energy to surrounding rock. *(geology)*

## Used by
- [fire](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-fire.combustion) (L21)
- [smith](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-smith.metalwork) (L22)
- [summer](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-summer.season) (L21)

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*Canonical: https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-heat.thermal*  
*Structured data: https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-heat.thermal.json*  
*Every definition provably resolves to space, time, energy and pattern.*