We use our __________ to breathe in and out.

Which gas do plants release into the air that humans and animals need?

Why do we need to breathe constantly, even when we are sleeping?

When you blow up a balloon, you are filling it with __________.

Plants use carbon dioxide from the air to make their food.

Air has weight and takes up space.

What is the main gas that makes up most of the air we breathe?

Air is something we can see and touch.

Name two things that can cause air pollution.

Air pollution can make it harder for people to breathe.

What is the most important gas in the air that living things need to breathe?

Which of these is NOT a good way to keep the air clean?

What happens when we breathe in?

Your friend says they can feel the wind but can't see the air. Explain to your friend why this is true.

Imagine you are playing outside and see a factory with a big chimney letting out dark smoke. What is happening to the air, and what might be a problem because of it?

The air around us is called the __________.

When we breathe out, we release a gas called __________ __________.

Why is it important to have clean air to breathe?

A farmer depends on rain for his crops to grow. One year, there is very little rain for many months. Explain how a long period without rain (a drought) is connected to the water cycle and what might happen to the farmer's crops.

Imagine you see dew drops on the grass in the morning. Which part of the water cycle is happening when these drops form?

Match the water cycle stage with its description:

After rain falls, water can gather in rivers, lakes, and oceans. This stage is called __________.

When water vapor in the sky cools down and turns back into tiny liquid water droplets, it forms __________.

When clouds get too heavy with water, the water falls back to Earth as precipitation. This is called condensation.

When water turns into a gas and goes up into the sky, what is this process called?

What is the main source of energy that makes the water cycle work?

Water can disappear from a puddle on a sunny day because it evaporates.

Which of these is NOT a form of precipitation?