Air Around Us quiz

The gas present in the largest amount in air is:

The percentage of oxygen in air is about:

Lime water turns milky when this gas is passed through it:

Water droplets on the outer surface of a glass of ice-cold water come from:

Which component of air is necessary for burning?

Earthworms breathe through their:

Which of the following works with the help of moving air?

The envelope of air around the Earth is called the:

Aquatic animals use oxygen that is:

Plants release oxygen into the air during:

How can you show that air is present in an empty bottle? (2 marks)

Why do we see dust particles in a beam of sunlight entering a dark room? (2 marks)

How does a sailing boat use air? (2 marks)

Name two gases that make up the small remaining part of air besides nitrogen and oxygen. (2 marks)

Why do we feel suffocated in a closed, crowded room? (2 marks)

How do plants living in soil get oxygen for their roots? (2 marks)

Why do we need to wash our hands and cover our noses near smoke and dust? (2 marks)

Give two uses of windmills. (2 marks)

Why does air bubble out when water is poured on dry soil? (2 marks)

Why are mountaineers given oxygen cylinders at very high altitudes? (2 marks)

A classroom contains 150 cubic metres of air. Calculate the volume of nitrogen and oxygen in it, taking nitrogen as 78 percent and oxygen as 21 percent. (3 marks)

Three candles were covered with glass jars of volumes 250 mL, 500 mL and 1000 mL at the same time. Arrange the candles in the order in which they will go out first to last, and give a reason. (3 marks)

A balloon contains 4 litres of air. Calculate the volume of oxygen and nitrogen it contains (oxygen 21 percent, nitrogen 78 percent), and the volume of the remaining gases. (3 marks)

A child breathes 20 times per minute and an adult 15 times per minute at rest. How many times does each breathe in one hour? How many more breaths does the child take in 2 hours? (3 marks)

In an activity, the water level in a glass jar inverted over a burning candle rises by about one-fifth of the jar's height. If the jar is 20 cm tall, how high does the water rise? Which component of air has been used up and why does the level rise? (3 marks)

Read the passage and answer the questions. Rani took a glass tumbler and filled it with ice-cold water. After a few minutes, she noticed tiny drops of water on the outer surface of the tumbler. She wiped them, but they appeared again. (i) What is the source of the water drops? (ii) Name the process by which these drops form. (iii) What does this activity tell us about air? (5 marks)

Read the passage and answer the questions. In a village, a windmill is used to draw water from a well and to run a small flour mill. On calm days, the windmill does not work and villagers have to use other means. (i) What makes the windmill work? (ii) Why does it not work on calm days? (iii) Name one more use of windmills today. (5 marks)

Read the passage and answer the questions. In a science lab, Vijay lit two identical candles. He covered one with a glass jar and left the other open. After some time, the covered candle went out, but the other continued to burn. (i) Why did the covered candle go out? (ii) Which component of air was used up? (iii) What does this show about the role of air in burning? (5 marks)

Read the passage and answer the questions. A fish tank in Neha's house has a small pump that keeps sending air bubbles into the water. When the pump stopped working for a day, the fish were seen near the surface gulping. (i) Why is the pump used in the fish tank? (ii) Why did the fish come near the surface? (iii) How do fish in rivers and ponds get oxygen? (5 marks)

Read the passage and answer the questions. A city has many vehicles and factories. People complain of coughing and the sky often looks hazy. The government plans to plant trees along the roads and to encourage public transport. (i) Name two pollutants that make the air hazy. (ii) How will planting trees help? (iii) Suggest one more way to improve air quality. (5 marks)

Draw a labelled diagram to show that air occupies space, using an inverted tumbler pushed into a bucket of water. Explain the observations when the tumbler is pushed straight down and when it is tilted. State two other activities that show air takes up space. (6 marks)

Describe an activity to show that air contains oxygen using a burning candle, an inverted glass jar and a plate of water. Draw a labelled diagram. Explain why the candle goes out and why water rises inside the jar. (6 marks)

Draw a pie chart showing the composition of air. Name all the components of air and state one importance of each of nitrogen, oxygen, carbon dioxide and water vapour for living organisms. (6 marks)

Draw a flow diagram showing how oxygen and carbon dioxide are exchanged between plants and animals in nature. Explain how this exchange keeps the balance of these gases in the atmosphere and what may happen if forests are cut down. (6 marks)

Draw a labelled diagram of a windmill. Explain how it works using moving air, list three uses of moving air in daily life, and explain how birds and gliders make use of air. (6 marks)