1
00:00:01,840 --> 00:00:08,060
Well, sound, light, and today, heat. With this, we finish the explanations of this unit.

2
00:00:09,119 --> 00:00:16,160
So, heat. What is heat? Heat is thermal energy, okay? Sometimes we confuse it with temperature,

3
00:00:16,500 --> 00:00:24,559
but temperature is a measure of this energy. It can be 0 degrees, 10, 20, okay? Here I've got this,

4
00:00:24,559 --> 00:00:35,259
you know look at this okay 36 as a human or 100 when water boils okay this is the measure this

5
00:00:35,259 --> 00:00:41,820
is temperature but heat is the thermal energy okay it can travel in any direction but it always flows

6
00:00:41,820 --> 00:00:51,000
from hot to cold all right from hot to cold and temperature measures how hot or cold something is

7
00:00:51,000 --> 00:00:56,920
the higher the temperature is the faster the molecules move think we here we got a pan

8
00:00:57,560 --> 00:01:06,359
okay the water is cold the molecules are still they are not moving however in a pan when we hit

9
00:01:06,359 --> 00:01:16,920
the water it starts moving the molecules look very fast uh like in like in lights we get two

10
00:01:16,920 --> 00:01:21,959
different types. We get artificial heat sources and natural ones. Okay, artificial

11
00:01:21,959 --> 00:01:26,819
heat sources like electrical energy and chemical energy, they can be transformed

12
00:01:26,819 --> 00:01:34,540
into heat energy. And natural heat sources, imagine life on Earth would not exist

13
00:01:34,540 --> 00:01:39,719
without the heat from the sun, the same as with light. And we also get heat from

14
00:01:39,719 --> 00:01:44,459
inside the Earth called geothermal energy. Remember from last unit we studied

15
00:01:44,459 --> 00:01:51,900
this different type non-renewable or renewable how was it renewable no yes your thermal energy

16
00:01:51,900 --> 00:01:59,579
was a renewable uh type of energy like solar one okay but both types are thermal energy

17
00:02:00,459 --> 00:02:07,340
heat can also change the state of matter you remember what were the states of matter we got

18
00:02:07,340 --> 00:02:17,819
three three solids liquids and gas okay so three possibilities with heats one when solids like

19
00:02:17,819 --> 00:02:25,659
butter and ice are heats they become liquids this is called melting or fusion you got the ice

20
00:02:25,659 --> 00:02:31,900
melting then when liquid water is heats it turns into a gas this is called evaporation think about

21
00:02:31,900 --> 00:02:36,759
the example of before and we were saying if we boil water we heat the temperature

22
00:02:36,759 --> 00:02:42,759
it can evaporate and finally as matter is heat it will expand or get bigger

23
00:02:42,759 --> 00:02:49,080
because the molecules move around more and faster this is called expansion the

24
00:02:49,080 --> 00:02:53,860
best example think about the hot air balloon when we heat the air contained

25
00:02:53,860 --> 00:03:01,180
inside it expands and this is why it's called hot air balloon well that's it

26
00:03:01,180 --> 00:03:07,740
sounds light and heat with this we have finished the explanations of the units

27
00:03:07,740 --> 00:03:13,120
during this week and next one we will be doing activities and practicing these

28
00:03:13,120 --> 00:03:16,539
units so don't worry if you don't understand something but please don't

29
00:03:16,539 --> 00:03:23,139
forget to ask your teachers as many times as you need all right well see you

30
00:03:23,139 --> 00:03:26,280
on Friday bye