1
00:00:00,370 --> 00:00:14,849
Heat is the transfer of thermal energy that passes from a body that has a higher temperature to one

2
00:00:14,849 --> 00:00:23,449
with a lower temperature. Heat can be transmitted in three ways conduction, convection and radiation.

3
00:00:23,449 --> 00:00:32,429
Conduction is the transfer of heat from a hot object to a cooler object when they are in contact.

4
00:00:33,149 --> 00:00:38,990
The molecules of the hot object move faster. When they collide with those of the cold object,

5
00:00:38,990 --> 00:00:44,750
they transmit that movement causing them to move faster and increase the temperature. At the same

6
00:00:44,750 --> 00:00:52,829
time, the temperature of the hot object will drop until both temperatures are equal. Heat can also

7
00:00:52,829 --> 00:00:57,869
travel through a single object because molecules collide with each other and transmit motion.

8
00:01:02,429 --> 00:01:13,629
Metals are very good thermal conductors, however, other materials such as wood are thermal insulators

9
00:01:13,629 --> 00:01:17,069
because they do not conduct heat easily.

10
00:01:17,069 --> 00:01:23,170
This experiment shows how heat travels through the spoon melting the wax and making the clips

11
00:01:23,170 --> 00:01:47,980
fall.

12
00:01:47,980 --> 00:01:52,980
is the circular movement that happens when warmer particles in a fluid, which

13
00:01:52,980 --> 00:02:00,299
are less dense, rise, while cooler particles, which are denser, drop. These

14
00:02:00,299 --> 00:02:07,599
can be applied to liquids and gases. This room here is filled with air. If we make

15
00:02:07,599 --> 00:02:14,979
some fire at the bottom, those particles, which are close to the fire, will heat up.

16
00:02:14,979 --> 00:02:19,860
When they are hotter, they are less dense than the other ones, so they will rise

17
00:02:19,860 --> 00:02:29,479
and that space will be filled by other cool particles. Then those cool particles

18
00:02:29,479 --> 00:02:33,300
will heat up and rise as the previous ones had done, and the process will be

19
00:02:33,300 --> 00:02:40,960
repeated again and again. And finally radiation, which is the process by which

20
00:02:40,960 --> 00:02:47,479
heat, in the form of electromagnetic waves, is emitted in all directions. The

21
00:02:47,479 --> 00:03:23,979
The best example is the heat of the Sun that travels to the Earth.