DELHI TEACHERS’ TRAINING COLLEGE

DEENPUR, NAJAFGARH, NEW DELHI – 110043(Affiliated to G.G.S.I.P. University, Delhi – 110075)

B.Ed. 2015 – 2017Semester - III

Submitted By:- Swati GhanselaEnrollment No.- 05940202115Batch- 2015-17

MULTIMEDIA MULTIMEDIA LESSON PLANLESSON PLAN

(Combustion and Flame)(Combustion and Flame)

General Objectives:-

i) To enable the students to understand the concept of Science

ii) To develop the logic and reasoning power of the students

iii) To arouse the interest of the students in the quantitative side of the world

Specific Objectives :-

1.Cognitive domain

(a) Knowledge level

The students will be able to

i. define combustion

ii. list the types of combustion

(b) Understanding level

The students will be able to

i. explain the process of combustion

ii. Understand the combustible and non combustible substances

Name of the School: BVM Public SchoolClass: 8th Subject: Science

Lesson PlanTopic: Combustion and Flame

(c) Application level

The students will be able to illustrate the types of combustion with example

(2) Affective Domain

The students will be able to acknowledge and associate the learning with real life.

(3) Psychomotor Domain

The students will be able to write the conditions of combustion.

Statement of Aim:-

Today we are going to study the concept of combustion and flame

Teaching Aid:- Power point presentation

Previous Knowledge:- Students are aware of fire

Recapitulation:-

Q1. What is combustion?

Q2. Explain fire.

Homework:-

Q. Write some combustible and non combustible substances.

Combustion A chemical process in which a substance reacts with oxygen to give off heat is called

combustion. The substance which undergoes combustion is called a combustible substance. It is also

called a fuel. Sometimes light is also produced during combustion either as a flame or as a glow. Air is necessary for combustion.

Types of combustion There are three main types of combustion. They are :-•Rapid combustion•Spontaneous combustion •Explosion

Rapid combustion:- is combustion in which a substance burns rapidly and produces heat and light with the help of external heat. Example:- burning of LPG.

Spontaneous combustion:- is combustion in which a substance burns spontaneously and produces heat and light without the help of external heat. Example:- phosphorus burns spontaneously at room temperature.

Explosion:- is a combustion in which a substance burns suddenly and produces heat, light and sound with the help of heat or pressure. Example:- explosion of crackers on applying heat or pressure.

Types of CombustionRapid combustion

Spontaneous combustion

Explosion

Ignition Temperature The lowest temperature at which a substance catches fire is called

its ignition temperature. combustible substance cannot catch fire or burn as long as its

temperature is lower than its ignition temperature. Kerosene oil and wood do not catch fire on their own at room

temperature. But, if kerosene oil is heated a little, it will catches fire.

Combustible substances

Substances which burn in air to produce heat and light are called combustible substances.

Example :- wood, coal, charcoal, kerosene, petrol, diesel, liquefied petroleum gas (LPG), compressed natural gas (CNG) etc.

Wood Coal LPG kerosene

Non-combustible Substances

 Any material that does not readily burn. For everyday use, most metals, rock, and glass are non-combustible. 

Drywall (sheetrock is a brand name) is made from gypsum rock, and is considered non-combustible- as is brick and concrete. Asbestos is very thoroughly non-combustible, but rarely used any more due to severe health hazards. 3 examples of non-combustible substances are rock, steel and water, sand etc.

Activity: Combustible and Non Combustible

Material Combustible Noncombustible

Wood

Paper

Iron nails

Kerosene oil

Stone piece

Straw

Charcoal

Matchsticks

Glass

Air is necessary for burning

(A) (b) (c)• Fix a lighted candle on a table. Put a glass chimney over the table and rest it on a few wooden blocks in such a way so that air can enter the chimney. Observe what happens to the flame.• Now remove the blocks and let the chimney rest on the table. Again observe the flame.• Then put a glass plate over the chimney. Observe the flame again.• The candle burns freely in (a) because air enters the chimney from below.• The candle stops burning in (b) because air does not enter the chimney from below.• The candle does not burn in (c) because air is not available.• This shows that air is necessary for burning.

Activity DemonstrationCandle Activity

Ignition Temperature • The minimum temperature at which a substance catches fire and burns is called its

ignition temperature.

• A substance will not catch fire and burn if its temperature is lower than its ignition temperature.

• Different substances have different ignition temperatures.

• Example:- the ignition temperature of kerosene is less than the ignition temperature of wood.

• Substances which have very low ignition temperature and can easily catch fire with a flame are called inflammable substances. Eg:- petrol, alcohol, LPG, CNG etc.

Inflammable Substances The substances which have very low ignition temperature and can

easily catch fire with a flame are called inflammable substances. Examples of inflammable substances are petrol, alcohol, Liquefied

Petroleum Gas (LPG).

Conditions necessary for combustion The conditions necessary for combustion are :-

I. Fuel.

II. Air (to supply oxygen).

III. Heat (to raise the temperature beyond the ignition temperature.

A substance will not burn without one or more of these conditions.

How do we control fire ? The conditions necessary for producing fire are :-

I.Fuel

II.Air (to supply oxygen)

III.Heat (to raise the temperature of the fuel beyond its ignition temperature).

Fire can be controlled by removing any one or more of these conditions.

A fire extinguisher cuts off the supply of air or brings down the temperature of the fuel or both and controls the fire.

Methods of controlling fire I) by using water :- water is the most common fire extinguisher. It can be used only when materials like wood , paper etc. Are on fire. Water cannot be used if electrical equipment's are on fire because water conducts electricity and can harm those trying to put out the fire. Water cannot be used to put out oil and petrol fires because they float on water and continue to burn.

Ii) by using carbon dioxide:- Carbon dioxide is the best fire extinguisher to put out fire caused by inflammable materials like oil and petrol and electrical equipments. Carbon dioxide is heavier than air and it covers the fire and cuts off the supply of oxygen and puts out the fire. Carbon dioxide is stored at high pressure as liquid in cylinders. Chemicals like sodium bicarbonate (baking soda), potassium bicarbonate produce carbon dioxide near the fire.

Chemicals used to turn off Fire

Video of methods of controlling fire

Flame

A flame is the visible, gaseous part of a fire. It is caused by a highly exothermic reaction taking place in a thin zone.

Very hot flames are hot enough to have ionized gaseous components of sufficient density to be considered plasma.

The substances which vaporise during burning, give flames. For example, kerosene oil and molten wax rise through the wick

and are vaporised during burning and form flames. Charcoal, on the other hand, does not vaporise and so does not

produce a flame.

Structure of a Flame

What is a Fuel? The sources of heat energy for domestic and industrial purposes

are mainly wood, charcoal, petrol, kerosene, etc. These substances are called fuels.

A good fuel is one which is readily available. It is cheap. It burns easily in air at a moderate rate. It produces a large amount of heat. It does not leave behind any

undesirable substances. There is probably no fuel that could be considered as an ideal fuel. Some fuels are cheaper than others.

Fuel Efficiency The amount of heat energy produced on complete combustion of 1

kg of a fuel is called its calorific value. The calorific value of a fuel is expressed

in a unit called kilojoule per kg (kJ/kg).

Fuel Calorific Value (kJ/kg)

Cow dung cake 6000-8000

Wood 17000-22000

Coal 25000-33000

Petrol 45000

Kerosene 45000

Diesel 45000

Methane 50000

CNG 50000

LPG 55000

Biogas 35000-40000

Hydrogen 150000

Burning of Fuels Leads to Harmful Products

1. Carbon fuels like wood, coal, petroleum release unburnt carbon particles. These fine particles are dangerous pollutants causing respiratory diseases, such as asthma.

2. Incomplete combustion of these fuels gives carbon monoxide gas. It is a very poisonous gas. It is dangerous to burn coal in a closed room. The carbon monoxide gas produced can kill persons sleeping in that room.

Global Warming & Acid Rain Combustion of most fuels releases carbon dioxide in the

environment. Increased concentration of carbon dioxide in the air is believed to cause global warming.

Burning of coal and diesel releases sulphur dioxide gas. It is an extremely suffocating and corrosive gas. Moreover, petrol engines give off gaseous oxides of nitrogen. Oxides of sulphur and nitrogen dissolve in rain water and form acids. Such rain is called acid rain. It is very harmful for crops, buildings and soil.

Precaution To Be Taken The use of diesel and petrol as fuels in automobiles is being

replaced by CNG (Compressed Natural Gas), because CNG produces the harmful products in very small amounts. CNG is a cleaner fuel.