CLASS-6 SUBJECT SCIENCE CHAPTER-9 THE LIVING ORGANISM AND THEIR SURROUNDINGS.

 EVENTS CONVENT HIGH SCHOOL

01/02/2022      CLASS- 6   SESSION 2021-22
SUBJECT : SCIENCE

CHAPTER-9
THE LIVING ORGANISM AND THEIR SURROUNDINGS 

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1.Fill in the blanks:
(a) The presence of specific features which enables a plant or an animal to live in a particular habitat is called adaptation.
(b) The habitats of the plants and animals that live on land are called terrestrial habitats.
(c)The habitats of plants and animals that live in water are called aquatic habitats.
(d) Soil, water and air are the abiotic factors of a habitats.
(e) Changes in our surroundings that make us respond to them are called stimuli.

 VERY SHORT ANSWER TYPE QUESTIONS

1. Name some plants found on mountains.
Ans: Oaks, Pinus and Deodars.

2. What is habitat?
Ans:. The place where organisms live and which provide food and safety for them is ‘called habitat.

3. Name a few habitats.
Ans: Forests, grassland, mountains, ponds and oceans etc.

4. Name two organisms that live in deserts.
Ans:  Cactus, camel, desert rat.

5. Name a few plants that live in ponds.
Ans:  Hydrilla, lotus, hyacinth etc.

6. Name the habitat where various types of fish live.
Ans:  Pond, river, sea.

7. Name a common thing in all fishes.
Ans:  Gills, streamlined body, fins, tail.

8. What is the function of gill?
Ans: Gills help the fish to absorb oxygen dissolved in water.

SHORT ANSWER TYPE QUESTIONS

1. What are the differences in the desert and sea regions?
Ans: In the sea, plants and animals are surrounded by salty water. Most of them use the air dissolved in water for breathing. In desert, a very little amount of water is available. It is very hot in the day time and very cold at night. The organisms breathe air from the surroundings.

2. What do you mean by term adaptation?
Ans: The presence of specific features or certain habits which enable a plant or an animal to live in its surroundings is called adaptation.

3. Explain the features offish which help it to adapt to live in water.
Ans:
(i) The shape of the fish is streamlined which help in the movement.
(ii) The slippery scales/skin on their bodies to protect them.

(iii) They have flat fins and tails which help them to swim, change direction and to keep the body balanced.
(iv) They have gills which help in breathing in water.

CLASS-8 SUBJECT SCIENCE CHAPTER-6 COMBUSTION AND FLAMES

 EVENTS CONVENT HIGH SCHOOL

01/02/2022      CLASS- 8   SESSION 2021-22
SUBJECT : SCIENCE

CHAPTER-6
COMBUSTION AND FLAMES

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Question 1.List conditions under which combustion can take place.
Answer:
Combustion can take place in the presence of:
(a) a combustible substance.
(b) oxygen, that is, the supporter of combustion.
(c) attainment of ignition temperature of the substance.

Question 2.Fill in the blanks.
(a) Burning of wood and coal causes pollutionof air.
(b) A liquid fuel, used in homes is LPG
(c) Fuel must be heated to its ignition temperature before it starts burning.
(d) Fire produced by oil cannot be controlled by water

Question 3.Explain how the use of CNG in automobiles has reduced pollution in our cities.
Answer:
The use of CNG in automobiles has reduced pollution in our cities as it is a quality fuel and has some benefits:
(a) It gives out less carbon dioxide gas, carbon monoxide gas, sulphur dioxide and nitrogen dioxide, which is beneficial as they play crucial role in global warming and acid rain.
(b) It leaves behind no residue after its combustion.

Question 4.Compare LPG and wood as fuels.
Answer:

LPG	Wood
(i) It does not cause pollution on combustion.	(i) It pollutes air on its combustion.
(ii) No smoke is produced.	(ii) It produces smoke.
(iii) It is a liquid fuel.	(iii) It is a solid fuel.
(iv) It has more calorific value (55000 kJ/kg).	(iv) It has less calorific value (17000 kJ/kg).
(v) It can be easily transported, as it is stored in cylinders.	(v) It can’t be transported easily like LPG fuels.

Very Short Answer Questions

Question 1.Name the most common fuel used in homes.
Answer:
Liquefied Petroleum Gas. (LPG)

Question 2.Name the most common fire extinguisher.
Answer:
Water

Question 3.What are the states in which a fuel may exist?
Answer:
A fuql may exist in solid, liquid or gaseous state.

Question 4.Name any two combustible substances.
Answer:
Charcoal, wood

Question 5.Does magnesium produce heat and light during its combustion?
Answer:
Yes, it does.

Short Answer Questions

Question 1.What does magnesium burn to form?
Answer:
Magnesium burns to form magnesium oxide and produces heat and light.

Question 2.What does coal produce during its combustion?
Answer:
Coal produces carbon dioxide, heat and light during its combustion.

Question 3.What is combustion?
Answer:
Combustion is a chemical process in which a substance reacts with oxygen to give off heat.

Question 4.Define ignition temperature of a fuel.
Answer:
The lowest temperature at which a fuel catches fire is called its ignition temperature.

Question 5.How does a matchstick catch fire?
Answer:
By rubbing a matchstick against a rough surface (friction), it attains its ignition temperature and thus catches fire.

CLASS-7 SUBJECT SCIENCE CHAPTER-4 HEAT

  EVENTS CONVENT HIGH SCHOOL

01/02/2022      CLASS- 7   SESSION 2021-22
SUBJECT : SCIENCE

CHAPTER-4
HEAT

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Q.1.Fill in the blanks
(a) The hotness of an object is detetmined by its ____________ .
(b) Temperature of boiling water cannot be measured by a ____________ thermometer.
(c) Temperature is measured in degree ____________ .
(d) No medium is required for transfer of heat by the process of ____________.
(e) A cold steel spoon is dipped in a cup of hot milk. It transfers heat to its other end by the process of ____________
(f) Clothes of ___________ colours absorb heat better than clothes of light colours.

Ans. (a) temperature (b) clinical (c) Celsius (d) radiation (e) conduction (f) dark

Very Short Answer Type

Question 1.In a mercury thermometer, the level of mercury rises when its bulb comes in contact with a hot object. What is the reason for this rise in the level of mercury? 
Answer:
As the temperature increases, then expansion in mercury takes place which leads to the rise in the level of mercury in thermometer.

Question 2.Shopkeepers selling ice blocks usually cover them with jute sacks. Explain why. 
Answer:As we know that jute sacks is thermal insulators, it helps ice not to be melt immediately. So, shopkeepers used to cover ice blocks with jute sacks.

Question 3.The radiators in cars are painted black. Explain why. 
Answer:Since, the black bodies are better radiators, so due to this reason, radiators in cars are painted black.

Question 4.To keep her soup warm, Paheli wrapped the container in which it was kept with a woollen clothes. Can she apply the same method to keep a glass of cold drink cool? Give reason for your Answer: 
Answer:
Yes, she can apply the same method to keep a glass of cold drink cool because wool is a thermal insulator, and it cannot allow to heat pass through it.

Short Answer Type

Question 1.The handle of a pressure cooker is covered with the thick plastic. Explain why?
Answer:
As we know that plastic is a bad conductor of heat due to which the heat from the cooker does not flow to its handle and we can hold it easily.
So, this is a reason because of which the handle of a pressure cooker is covered with the thick plastic.

Question 2.Differentiate between two modes of transfer of heat, i.e. convection and conduction?
Answer:
Difference between convection and conduction

Conduction	Convection
The mode of transfer of heat from the hotter part material to its colder part or from a hot material to a cold material in contact with it without the movement of material as a whole. So, this phenomenon is known as conduction	The mode of transfer of heat from the hotter part of a fluid to its colder parts by the movement of liquid itself. So, this phenomenon is known as convection.
In all the solids, heat is transferred by the process of conduction	In all the liquids and gases, heat is transferred by the process of convection

Question 3.Describe the effects of heat?
Answer:
The effects of heat are
(i) When an object is heated, then it becomes hotter and may get expand. So, in this heat may change the state of the body like ice can also get change into the water.
(ii) Heat sometimes acts as a catalyst to speed up the chemical reaction.
(iii) Heat can even kill the bacteria as well.

Question 4.The freezer is located at the top of the refrigerator. Explain why?
Answer:
The freezer is located at the top of the refrigerator. It is because the air inside and around the compartments of freezer gets cool and move downwards and on the other side, the lesser cool air moves upward to get cooled.
So, as a result of this, convection of heat are setup in the air and the tower section of the . refrigerator also gets cooled faster. .