# Ignition Temperature

Ignition Temperature

### Transcript

• 0:0Ignition temperature. It is one of the
• 0:7
• 0:7essential conditions required for a
• 0:9
• 0:9substance to burn or for a substance to
• 0:12
• 0:12start its combustion. What are the other
• 0:15
• 0:15conditions? We know that the other
• 0:18
• 0:18conditions are for combustion, a fuel is
• 0:20
• 0:20required and to burn the fuel, oxygen is
• 0:24
• 0:24required. An ignition temperature is the
• 0:26
• 0:26third essential condition for
• 0:28
• 0:28combustion to take place. Let us understand
• 0:31
• 0:31this ignition temperature with
• 0:33
• 0:33the help of some examples. Take an
• 0:36
• 0:36example of a candle. Does a candle burn
• 0:39
• 0:39on its own? No. You have to light it
• 0:43
• 0:43with a match stick that means you have
• 0:46
• 0:46to give it some heat.
• 0:48
• 0:48Ok. Take the example of a wood. Can we burn
• 0:52
• 0:52the wood with the matchstick? No. We
• 0:55
• 0:55have to burn it with some more flame.
• 0:58
• 0:58Either you burn it with the paper or
• 1:0
• 1:0you burn it with using kerosene oil.
• 1:4
• 1:4One more thing, have you seen forest fires? When
• 1:9
• 1:9does this forest fire occur? Does it
• 1:11
• 1:11occur in all the seasons? No. It
• 1:15
• 1:15occurs when there is extreme amount of
• 1:17
• 1:17heat in the atmosphere and due to which some
• 1:21
• 1:21grasses catch fire and slowly from these
• 1:24
• 1:24grasses, entire forests catches fire.
• 1:27
• 1:27So all these examples, tell us that
• 1:30
• 1:30different substances require different
• 1:32
• 1:32amount of heat to burn. More the heat
• 1:36
• 1:36required, more will be the temperature
• 1:38
• 1:38required for the substance to burn. That
• 1:41
• 1:41means, we can say, that the lowest
• 1:43
• 1:43temperature required for the substance
• 1:46
• 1:46to burn will be known as its ignition
• 1:49
• 1:49temperature. So, what is the definition of
• 1:51
• 1:51ignition temperature. The lowest
• 1:54
• 1:54temperature required for the substance
• 1:56
• 1:56to burn is called its
• 1:58
• 1:58ignition temperature. So, now let us
• 2:1
• 2:1understand this ignition temperature
• 2:3
• 2:3better with some activity. We take two
• 2:7
• 2:7paper cups. In one of the cups, we put 50
• 2:10
• 2:10ml of water.
• 2:11
• 2:12Now, let's start burning both the cups
• 2:14
• 2:14with the candle.
• 2:16
• 2:16What are you observing here? You observe
• 2:19
• 2:19that the empty paper cup has started burning
• 2:22
• 2:22whereas the paper cup of water has yet not
• 2:27
• 2:27started burning.
• 2:28
• 2:28What does this indicate? This indicates that the
• 2:32
• 2:32empty paper cup has reached its ignition
• 2:34
• 2:34temperature. So, it has started burning
• 2:36
• 2:36because we're supplying continuous heat
• 2:39
• 2:39to it. But in the second case, the cup with
• 2:42
• 2:42water has not reached its ignition
• 2:44
• 2:44temperature but we're still supplying heat
• 2:47
• 2:47to it and where is that heat going? Like
• 2:50
• 2:50heat is being transferred to the water
• 2:52
• 2:52in the cup
• 2:53
• 2:53due to which the paper cup does not
• 2:57
• 2:57catch fire because the ignition
• 3:0
• 3:0temperature of the paper cup has not
• 3:1
• 3:1met. So, this activity clarifies that
• 3:5
• 3:5ignition temperature is very much
• 3:8
• 3:8essential for a substance to start
• 3:9
• 3:9burning. It is the third most requirement
• 3:13
• 3:13for starting combustion. Ok. Moving
• 3:17
• 3:17further, we have two substances - kerosene
• 3:20
• 3:20and wood. We tried burning both of them.
• 3:23
• 3:23Which substance will burn quickly? Kerosene,
• 3:27
• 3:27right? and wood will take a little more
• 3:29
• 3:29time to burn. That means, the heat
• 3:32
• 3:32required by kerosene to burn is less compared
• 3:34
• 3:34to wood. So, the ignition temperature of
• 3:37
• 3:37kerosene, I can say is lower than
• 3:40
• 3:40wood. Ok. These substances which catch
• 3:44
• 3:44fire very soon are called inflammable
• 3:48
• 3:48substances. The ignition temperature are
• 3:50
• 3:50much lower. So, how can we define
• 3:53
• 3:53inflammable substances? The substances
• 3:56
• 3:56which catch fire very soon or the
• 3:58
• 3:58substances whose ignition temperature is
• 4:1
• 4:1very low are called inflammable substances.
• 4:5
• 4:5Now, the other examples of inflammable
• 4:8
• 4:8substances are petrol, diesel, CNG, LPG all
• 4:14
• 4:14these fuel are much much inflammable.
• 4:17
• 4:17Ok. You have to keep them stored in such
• 4:20
• 4:20a way, that
• 4:21
• 4:21they don't catch fire easily. So, what have
• 4:24
• 4:24you learned about ignition temperature?
• 4:26
• 4:26That ignition temperature is very much
• 4:29
• 4:29essential for a substance to burn. It
• 4:31
• 4:31is the third condition required for a
• 4:33
• 4:33substance to burn along with fuel and
• 4:35
• 4:35oxygen and what is the next thing? We
• 4:38
• 4:38learned that there are certain
• 4:40
• 4:40substances who have ignition temperature
• 4:42
• 4:42much lower than others. Due to which they
• 4:45
• 4:45catch very soon. So such subtances are
• 4:48
• 4:48called inflammable substances. Examples are
• 4:51
• 4:51Kerosene, petrol, diesel, LPG, CNG
• 4:56
• 4:56and many more.