Points to remember

Points to remember

* The main source of heat is sun, we can obtain heat from combustion, friction, and electricity.

* Heat is an energy that raises the temperature of a thing by causing the molecules in that thing to move faster

* Heat is the total Kinetic energy of constituent particles of objects.

* SI unit of Heat is joule (J).

* The measurement of warmness or coldness of a substance is known as its temperature.

* SI unit of temperature is kelvin.

* Temperature determines the direction of flow of heat when two bodies are placed in contact.

* Two objects are said to be in thermal contact if they can affect each other’s temperature.

* Thermal equilibrium exists when two objects in thermal contact no longer affect each other’s temperature.

* Most substances expand when heated and contract when cooled. The expansion of a substance on heating is called the thermal expansion of that substance.

* A solid has a definite shape, so when a solid is heated, it expands in all directions i.e., in length, area and volume, all increase on heating.

ICT Corner

Heat

Through this activity you will be able to understand the ‘Thermal Energy Transfer'.

Step 1: Use the given URL in the browser. ‘THERMAL ENERGY TRANSFER activity page will open.

Step 2: Click the = icon on the top left of the activity window, a list will drop down, from the list select a title.

Step 3: A small flash video window will open, click the play icon to play the video and observe.

Step 4: From the list select any title under the 'Example" list, a small flash activity window will open, click anyone of the tab given under the window to know the process of thermal transfer. Repeat the activity with different titles from the menu.

THERMAL ENERGY TRANSFER URL:

http://d3tt741pwxqwm0.cloudfront.net/WGBH/conv16/conv16-int-thermalenergy/index.html#/intro

*Pictures are indicative only