Class 8 Combustion and Flame

• Science
• Secondary Education

Welcome!

Welcome To The Class!

Welcome to the class!

Let's revise the netiquettes of online learning.

Doubts?

Any doubts during the class can be posted in the space given by clicking on the Doubts Icon in the right bottom corner.

If you have any doubts during the class, please post it in the doubts section. I will answer your questions at the end. 

Red for working in total silence, no questions may be asked; orange if questions may be asked to the teacher or with each other; green is for normal discussion and collaboration.

Points To Note:

Timer is used for activities and must be completed within the given time.

Riddle time!

Give me food, and I will live. Give me water, and I will die. What am I?

The correct answer is FIRE

Do you know what is a chemical reaction? Explain in your terms.

Stepping Stones

We all celebrate on different occasions. Diwali is the festival of lights. Many things we see or do on this day involve combustion reaction like burning crackers and lighting lamps. You might be wondering what is a combustion reaction.

Let us know more about the combustion reaction.

Learning Objectives

* To define the term 'combustion reaction'

* To distinguish between combustible and non-combustible substances.

* To know the meaning of ignition temperature.

* To know about the essentials or requirements to produce fire and the principle of fire extinguisher.

* To understand different types of combustion.

What comes to your mind
when you hear 'combustion' ?

Combustible & Non-Combustible substances

Combustible substances:  Substances that catch fire easily in the presence of oxygen are called combustible or fuel. They are mostly made up of hydrocarbons. When these substances burn, carbon dioxide and water are formed as products, and heat and light are released as by-products. For example, wood, paper, coal.

Non-Combustible substances:  Substances which do not burn or catch fire in the presence of oxygen. For example, sand, rock, water.

Why does the fire goes off when water is poured over burning wood?

Query 

Time

Teachers will check the doubts section and answer students questions.

Learning Objectives

* To define the term 'combustion reaction'

* To distinguish between combustible and non-combustible substances.

* To know the meaning of ignition temperature.

* To know about the essentials or requirements to produce fire and the principle of fire extinguisher.

* To understand different types of combustion.

COMBUSTION

To burn something you need:

• oxygen
• fuel
• temperature

To extinguish a fire you need to:

• take away the oxygen
• take away the fuel
• or lower the temperature

How Do We Control Fire?

Fuel, air and heat are the three mandatory requirements for combustion. Elimination of any one of these requirements will extinguish fire.

Water can be used to extinguish fire. As water brings down the temperature and hence fire extinguishes in the absence of heat. But this method can only be used if fire is due to wood or paper. If it is an electrical fire then this would be dangerous method to use as water conducts electricity and hence may harm you. This method won’t work out in case of oil or petrol fire too as oil floats on water and hence continues to burn.

In such cases using fire extinguishers will be a brilliant idea as it contains carbon-dioxide. Carbon-dioxide being heavier than oxygen covers the fire and breaks the contact between fire and the oxygen. In addition to this it also cools down the fuel because CO2 is stored under pressure in cylinders and when released it expands and cools down. Moreover it does not harm the electrical equipment too.

The type of combustion reaction that occurs with a great speed producing an enormous heat & light in a short time.

The type of combustion reaction that occurs on its own, without the submission of heat.

The type of combustion reaction that occurs with the evolution of tremendous amount of heat, light, gases and sound.

Rapid Combustion

Spontaneous Combustion

Explosion

Learning Objectives

* To define the term 'combustion reaction'

* To distinguish between combustible and non-combustible substances.

* To know the meaning of ignition temperature.

* To know about the essentials or requirements to produce fire and the principle of fire extinguisher.

* To understand different types of combustion.

https://quizlet.com/595172874/match

Learn the new words

Query 

Time

Teachers will check the doubts section and answer students questions.

Combustion Activity I

Let's understand this topic even better. Click on the given link to open the activity.

https://www.yenka.com/activities/Combustion_-_Activity/

Combustion Activity II

Let's interact with the video. Click on the given link to open the activity. Watch the video and answer the questions.

https://app.playpos.it/go/listcode/1277315/1521132/1070250/0/Quiz-and-Video-on-Combustion-and-Flame

Which reaction is combustion?

1. When things burn due to oxygen
2. When things burn due to carbondioxide
3. When things do not burn
4. When only paper burns

Which of the following is combustible?

1. Iron nail
2. Glass
3. Stone pieces
4. Paper

Oxygen is always needed for combustion

1. True
2. False

What are the combustion products when burning a candle?

1. Water and oxygen
2. Water and carbon dioxide
3. Candle wax and oxygen
4. Candle wax and carbon dioxide

Combustible substances are also known as

1. illuminous
2. inflammable
3. flaming
4. non-flammable

Which of the following is an example of inflammable substance?

1. Iron
2. Glass
3. LPG
4. Stone

https:

Quizziz 

COMBUSTION AND FLAME

Quiz

https://quizizz.com/join/quiz/609b982e033577001dab5d0d/start?studentShare=true

Microsoft Forms

Students Link:

https://forms.office.com/Pages/ResponsePage.aspx?id=ukNcCbKsJ0eMhSvNsSiy1ldcxNpssMBFll5JGGMBfz1UOEdRUUFBT1RGOEg0M1BMTEo0QlQ5VkhHSS4u

Duplicate Link:

Click Here

Reference Links

Career Launcher Notes

Learn CBSE Extra Questions

What you have learnt today?

1. The substances which burn in air are called combustible.
   
2. Oxygen (in air) is essential for combustion.
   
3. During the process of combustion, heat and light are given out.
   
4. Ignition temperature is the lowest temperature at which a combustible substance catches fire.
   
5. Inflammable substances have very low ignition temperature.
   
6. Fire can be controlled by removing one or more requirements essential for producing fire.
   
7. Water is commonly used to control fires.
   
8. Water cannot be used to control fires involving electrical equipment or oils.
   
9. There are various types of combustions such as rapid combustion, spontaneous combustion, explosion, etc

What will you learn next class?

Flame

Structure of Flame

What is Fuel?

Fuel Efficiency

Burning of Fuels leads to Harmful Products

Thank You

For your attention!

Presentation by Anshika