Water Cycle Basics
Grade 2 · Science · Study Guide
Find out how water moves from the ground to the sky and back again in a never-ending cycle.
Water on Earth is always moving in a cycle called the water cycle. It never stops, and it has been going on for billions of years.
The first step is evaporation. When the sun heats water in oceans, lakes, and rivers, the water turns into water vapor, which is a gas. The water vapor rises up into the air. You cannot see water vapor, but it is all around us.
As water vapor rises higher into the sky, it cools down. When it cools, it changes back into tiny water droplets. These droplets come together to form clouds. This step is called condensation.
When lots of water droplets gather in a cloud, the cloud gets heavy. The water falls back to the ground as precipitation. Precipitation can be rain, snow, sleet, or hail, depending on how cold the air is.
When rain falls on the ground, it collects in rivers, lakes, and oceans. Some of it soaks into the ground. Then the sun heats the water again, and the whole cycle starts over.
The water cycle is very important because it brings fresh water to plants, animals, and people all over the world. The same water has been going around and around for millions of years!
Key terms
- water cycle
- The never-ending movement of water from Earth to the sky and back again
- evaporation
- When liquid water is heated and turns into water vapor, a gas
- condensation
- When water vapor cools and changes back into tiny liquid water droplets to form clouds
- precipitation
- Water that falls from clouds to the ground as rain, snow, sleet, or hail
- water vapor
- Water in the form of a gas that floats in the air
- collection
- When water gathers in oceans, rivers, lakes, or the ground after precipitation
Flashcards
- water cycle
- The path water takes as it moves from Earth to the sky and back
- evaporation
- When liquid water turns into water vapor (gas) due to heat
- condensation
- When water vapor cools and forms tiny droplets that make clouds
- precipitation
- Rain, snow, sleet, or hail falling from clouds
- water vapor
- Water in gas form floating in the air
- cloud
- A collection of tiny water droplets floating high in the sky
- collection
- When water gathers in oceans, lakes, rivers, or underground
- sun
- The energy source that drives evaporation and powers the water cycle
Questions
What is the first step of the water cycle?
- Condensation
- Precipitation
- Evaporation
- Collection
Show answer
Answer: Evaporation
Evaporation is the first step in the water cycle. The sun heats liquid water, turning it into water vapor that rises into the sky.
Clouds are made of tiny water droplets.
Show answer
Answer: True
Clouds form when water vapor cools and becomes millions of tiny liquid water droplets that group together.
Water that falls from clouds to the ground is called ________.
Show answer
Answer: precipitation
Precipitation is any form of water that falls from clouds, including rain, snow, sleet, and hail.
What causes water to evaporate?
- Cold air
- Heat from the sun
- Wind blowing
- Clouds forming
Show answer
Answer: Heat from the sun
Heat from the sun warms the water in oceans, lakes, and rivers, causing it to evaporate and turn into water vapor.
The water cycle only happens during summer.
Show answer
Answer: False
The water cycle happens all year long in every season, in all parts of the world.
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