CBSE Class 3 Science Worksheet D

Two bodies of equal weight but having different shape produce different pressure

 

Pressure in Liquids

Like solids, liquids have weight. As a result of this weight liquids create pressure on the base and the walls of their container. The pressure of a liquid depends on the depth. The pressure created/produced/ by a liquid increases with increase in depth.

But the pressure of a liquid decreases with decrease in depth. Thus we can conclude that pressure of a liquid has direct relationship with depth. 

 

pressure of liquid at different depth

 

Pressure in Gases

Like solids and liquids, gases occupy space. Air molecules fill up any empty spaces available indefinitely. They create pressure on the wall of lightly closed container.

 

Atmospheric Pressure

 

We live in an ocean of air. This ocean of air that covers the Earth is called atmosphere. It produces on everything its weight rests. We don’t feel this pressure because it acts on us equally in all directions.

Thus the force used to push the nail high pressure. This high pressure easily pushes the nail into the wood.

 

2. A knife is used to cut various objects. We sharpened when it gets blunt. A sharpened knife blade rests on small area of the object to be cut. Thus the force used to cut the object has high pressure. This high pressure enables us to cut the object easily.

3. After the eggs are laid, what do bird do to make them hatch?

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V. Look at the diagram and answer the given questions. 

1. Identify the bird.
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2. What type of beak does it have?
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3. Why sparrows are called Omnivores?
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VI. Give Reasons. 
1. Why does every food chain begin with plants?
2. Why do birds build nests in places that are difficult to see or reach?

VII. Differentiate between the following.

Q.1 Name the following:

1. A bird which weaves grass in and out to make its nest._____________

2. Collects a few sticks to make a cup-shaped nest._____________

3. Its front toes are joined by skin. ._____________

4. Collects pebbles and stones to make a nest. ._____________

5. It makes its nest in the hollow of tree. ._____________

6. Uses its beak like a needle to sew leaves with materials like threads and wool.

7. cannot fly but can run at a speed of 70 km/hr. ._____________

8. A body part of a bird which act as a rudder of boat ._____________

9. A bird’s body is covered with it. ._____________

10. Birds built nest to lay._____________

Q.2 Give two examples for each:

1. Flesh eating birds: ._____________, ._____________

2. Perching bird: ._____________, ._____________

3. scratching bird: ._____________, ._____________

4. Climbing bird: ._____________, ._____________

5. Swimming bird: ._____________, ._____________

6. Wading bird: ._____________, ._____________

7. Wings movement: ._____________, ._____________

Q.3 Read the clues and unscramble the words:

1. It has short, hard and horny beaks to crush grains and seeds. P_G__ON_

2. It has strong and chisel shaped beak. W_ _ DP_C_ER.

3.It uses its beak like a needle to sew leaves to make nest. TA_ _ L_ _. B_ R _

4. It cover the body of birds. D_WN _ _ A _ HE _

Q.1 Define the following term.
1. Herbivores : 2. Carnivores
3. Omnivores: 4. Domestic animals :

Q.2 Answer the following in one word.
1. I have a long trunk to suck water and to have shower also.
2. I have a long sticky tongue catch insects.
3. I am herbivore and gives milk.
4. I suck the blood of other animals.
5. I am a bird and an omnivore.
6. I am domestic animal also known as the ship of desert.
7. I lap milk and water and also eat fish.
8. I am a grazing animal and chew cud.
9. I am herbivore and gnaw the food.
10. All food chains begin from it.

Q.3 Fill in the blanks.
1. Animals need food to_______ , to get energy and to stay _______.
2. _______and _______ are energy giving food.
3. _______and _______are milk producing food.
4. _______ have very sharp front teeth.
5. _______have very sharp, pointed and curved teeth.

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