Air Form 1

What are the three most common gases in the Earth's atmosphere?

• Oxygen, nitrogen, and carbon dioxide

• Oxygen, helium, and neon

• Carbon dioxide, methane, and nitrogen

Answer explanation

Oxygen makes up about 21% of the Earth's atmosphere, while nitrogen makes up about 78%. Carbon dioxide is a much smaller percentage of the atmosphere, but it is still important because it contributes to the greenhouse effect and helps regulate the Earth's temperature.

What happens during combustion?

• Heat and light are produced

• Oxygen is consumed and carbon dioxide is produced

• Energy is created and water is produced

Answer explanation

Combustion is a chemical reaction that occurs when a fuel (like gasoline or wood) reacts with oxygen to produce heat, light, and new compounds. One of the most common byproducts of combustion is carbon dioxide, which is released into the air.

Which of the following is an example of a renewable energy source?

• Coal

• Oil

• Wind

Answer explanation

Renewable energy sources are those that can be replenished over time, unlike fossil fuels that take millions of years to form. Wind is a renewable energy source because it is powered by the sun and will never run out.

What is the most common cause of air pollution?

• Natural disasters

• Industrial activity

• Cars and trucks

Answer explanation

While air pollution can come from many sources, transportation is a major contributor. Cars and trucks release pollutants like carbon monoxide and nitrogen oxides, which can harm human health and the environment.

How does air pollution affect the environment?

• It causes climate change

• It damages plants and animals

• It makes the air smell bad

Answer explanation

Air pollution can harm plants and animals in a number of ways. For example, acid rain (which is caused by air pollution) can damage forests and waterways, while ozone (another air pollutant) can harm plants and crops.

Which of the following is a greenhouse gas?

• Oxygen

• Nitrogen

• Carbon dioxide

Answer explanation

Greenhouse gases are those that trap heat in the Earth's atmosphere, which contributes to the greenhouse effect and global warming. Carbon dioxide is one of the most important greenhouse gases, along with methane and water vapor.

How does air pressure change with altitude?

• It stays the same

• It decreases

• It increases

Answer explanation

Air pressure is the force that air exerts on the Earth's surface. As you move higher in the atmosphere, there is less air above you, so the air pressure decreases. This is why it can be harder to breathe at high altitudes.

What can individuals do to reduce air pollution?

• Drive less

• Plant trees

• Turn off lights when not in use

Answer explanation

There are many things that individuals can do to reduce their impact on the environment, but one of the most effective is to drive less. This can mean carpooling, taking public transportation, or even biking or walking instead of driving.