Lesson 13 of 15
The big picture
Show on a big screenLeft alone, heat goes from hot to cold. Only the way it travels changes.
| Idea | Remember | Example |
|---|---|---|
| Heat vs temperature | Temperature is a number. Heat moves to change it. | 6 mugs need 6 × the heat of 1 mug for the same rise |
| Which way | Left alone: hot to cold. Stops when both are the same. | blocks at 80 °C and 20 °C both end at 50 °C |
| Conduction | Along a solid. The solid stays in place. | steel spoon in hot dal |
| Convection | Warm liquid or gas rises. Cool part sinks. | water in a pan, sea breeze |
| Radiation | Nothing in between is needed. | the Sun warming the Earth |
| Surfaces | Dark, dull surfaces take in more heat. | a dark, dull tank gets warmer |
| Insulators | Poor conductors slow heat down. | wooden handle, quilt |
| Water cycle | The Sun heats water into vapour. Cooled vapour makes clouds. Clouds give rain or snow, and the water flows back. | sea to cloud to rain |
| Seeping | Gravel lets water through fastest. Sand is slower. Clay is slowest. Wide gaps let water through faster. These rules are for packed ground. | gravel, sand, clay |
| Breezes | By day, cool air moves from sea to land: a sea breeze. At night it moves from land to sea: a land breeze. | wind blows the other way at night |
| Ice stupas | An ice stupa freezes winter water into a cone of ice. The cone melts slowly and gives water in spring. | Ladakh |
Now open Chapter 7, Heat Transfer in Nature, in your NCERT book. Ask of each question: what carried the heat?