Class 5 Science - Air and Water - CBSE Worksheets Solutions - 2

Q1: Fill in the Blanks

(i) Air is a _________ of gases.
Ans: Air is a mixture of gases.
Air is not composed of a single gas but is a combination of various gases, including nitrogen, oxygen, carbon dioxide, and others.

(ii) _________ is the most common gas in the air. 
Ans: Nitrogen is the most common gas in the air. 
Nitrogen makes up about 78% of the Earth's atmosphere, making it the most abundant gas.

(iii) The process of taking in air containing oxygen into the body and giving out carbon dioxide is called _______.
Ans: The process of taking in air containing oxygen into the body and giving out carbon dioxide is called respiration.
Respiration is the process by which living organisms inhale oxygen and exhale carbon dioxide.

(iv) The layer of gases surrounding the Earth is known as the ________.
Ans: The layer of gases surrounding the Earth is known as the atmosphere.
The atmosphere is the layer of air surrounding our planet, held in place by gravity.

(v) _______ is the process by which water changes into water vapour.
Ans: Evaporation is the process by which water changes into water vapour.
Evaporation occurs when water is heated and changes from a liquid to a gaseous state, rising into the atmosphere.

Q2: Match the Column

Match the items in Column A with their respective descriptions in Column B.Ans: 
Oxygen - d. Responsible for photosynthesis in plants
Oxygen is essential for the process of photosynthesis in plants, during which they produce glucose and release oxygen.
Nitrogen - b. Most abundant gas in the Earth's atmosphere
Nitrogen is the most abundant gas in the Earth's atmosphere. 
Gills - e. Organs for breathing in fish and amphibians
Gills are respiratory organs in fish and amphibians that allow them to extract oxygen from water.
Evaporation - c. Process of converting water into vapour
Evaporation is the process of converting liquid water into water vapour, which then rises into the atmosphere.
Chlorophyll - a. Essential for the survival of aquatic life
Chlorophyll is a green pigment found in plants that plays a vital role in photosynthesis, not directly related to aquatic life.

Q3: True or False

(i) Air is composed of only one gas.
Ans: False
Air is a mixture of multiple gases, including nitrogen, oxygen, carbon dioxide, and others.

(ii) All living organisms need air to survive.
Ans: True
All living organisms require oxygen present in the air to carry out respiration, a vital process for survival.

(iii) The ozone layer protects us from the harmful ultraviolet rays of the sun.
Ans: True
The ozone layer in the atmosphere absorbs harmful ultraviolet radiation from the sun, protecting life on Earth.

(iv) Ice is an example of water in the liquid state.
Ans: False
Ice is the solid state of water, not the liquid state. Water in its liquid state is found at room temperature.

(v) Plants release oxygen during photosynthesis.
Ans: True
During photosynthesis, plants produce oxygen as a byproduct, which is released into the atmosphere.

Q4: Arrange in Correct Order

Arrange the following steps in the correct order to explain the water cycle.
(a) Precipitation
(b) Evaporation
(c) Condensation
(d) Collection
(e) Runoff
Ans: The correct order of the water cycle is as follows:
(b) Evaporation
(c) Condensation
(a) Precipitation
(d) Collection
(e) Runoff

• Evaporation: Water from oceans, lakes, and rivers evaporates due to heat from the sun, turning into water vapour.
• Condensation: The water vapour rises, cools, and condenses to form tiny water droplets, creating clouds.
• Precipitation: The water droplets in clouds combine and fall back to the Earth's surface as rain, snow, sleet, or hail.
• Collection: The water accumulates on the Earth's surface, forming rivers, lakes, and other bodies of water.
• Runoff: Excess water flows over the land and returns to the oceans, completing the water cycle.

Q5: Choose the Odd One Out

(i) Nitrogen, Oxygen, Water Vapour, Carbon Dioxide
Ans: Water Vapour
Nitrogen, oxygen, and carbon dioxide are gases present in the Earth's atmosphere, while water vapour is water in its gaseous form.

(ii) Lake, River, Pond, Glacier
Ans: Glacier
A glacier is a large mass of ice, while the other options are bodies of water.

(iii) Respiratory System, Circulatory System, Digestive System, Solar System
Ans: Solar System
The first three options are human body systems, while the last option refers to our solar system.

(iv) Boiling, Freezing, Melting, Precipitation
Ans: Precipitation
Boiling, freezing, and melting are phase changes of matter, while precipitation refers to rain, snow, or other forms of water falling from the sky. It is a weather phenomenon, not a phase change process.

(v) Atlantic, Pacific, Indian, Earth
Ans: Earth
The first three options are names of oceans, while "Earth" is the name of our planet.

Q6: Short Answer Questions

(i) What is the atmosphere, and what is its function?
Ans: The atmosphere is a thick layer of air surrounding the Earth, acting like a protective blanket that sustains life by providing gases like oxygen and carbon dioxide.

(ii) What is the troposphere?
Ans: The troposphere is the lowest atmospheric layer, where clouds form, weather changes occur, and it provides the air needed for breathing.

(iii) What is the importance of the ozone layer?
Ans: The ozone layer in the stratosphere absorbs harmful ultraviolet rays from the sun, protecting life on Earth from radiation.

(iv) Why is water called the "universal solvent"?
Ans: Water is known as the universal solvent because it can dissolve many substances, making it essential for life processes and industries.

(v) What are the two main ways to remove insoluble impurities from water?
Ans: Insoluble impurities are removed using sedimentation and decantation, where particles settle at the bottom, and filtration, where impure water passes through a filter.