The Water Cycle
Grade 3 · Science · Study Guide
Follow water as it moves from oceans to clouds to rain and back again.
The water on Earth today is the same water that dinosaurs drank millions of years ago! That's because water never really disappears — it just keeps moving in a continuous loop called the water cycle.
The water cycle has four main stages. Evaporation is when the Sun heats water in oceans, lakes, and rivers, turning liquid water into water vapor — an invisible gas that rises into the air. Transpiration is similar but happens when plants release water vapor through their leaves.
As water vapor rises into the cooler upper atmosphere, it cools down and turns back into tiny liquid water droplets. This is called condensation. These droplets cluster around dust particles and form clouds. When enough droplets combine and become heavy enough, water falls back to the ground as precipitation — which can be rain, snow, sleet, or hail depending on temperature.
Once precipitation lands, it can do different things. Some runs off into rivers and streams (runoff), some soaks into the ground (groundwater), and some evaporates again right away. The Sun provides the energy that keeps this whole cycle going, non-stop, all over our planet.
Key terms
- water cycle
- The continuous movement of water through Earth's systems — from land to sky and back
- evaporation
- Liquid water turning into water vapor due to heat
- condensation
- Water vapor cooling and turning back into liquid water droplets
- precipitation
- Water falling from clouds as rain, snow, sleet, or hail
- runoff
- Water that flows over land into rivers and streams after precipitation
Flashcards
- water cycle
- The continuous movement of water between Earth's surface and atmosphere
- evaporation
- Liquid water changing to water vapor when heated
- condensation
- Water vapor cooling and changing back into liquid droplets
- precipitation
- Water falling from clouds as rain, snow, sleet, or hail
- transpiration
- Water vapor released by plants through their leaves
- runoff
- Precipitation that flows over land surface into streams and rivers
Practice questions
What provides the main energy that drives the water cycle?
- The Moon
- The Sun
- Wind
- Ocean currents
Show answer
Answer: The Sun
The Sun heats surface water, causing evaporation. Without solar energy, water would not evaporate and the cycle would stop.
Condensation happens when water vapor cools and turns into liquid.
Show answer
Answer: True
Condensation is the opposite of evaporation. When warm, moist air rises and cools, the water vapor condenses into tiny droplets that form clouds.
Water falling from clouds as rain or snow is called ___.
Show answer
Answer: precipitation
Precipitation includes all forms of water falling from clouds: rain, snow, sleet, freezing rain, and hail. Temperature determines which form it takes.
Which stage of the water cycle involves liquid water turning into water vapor?
- Condensation
- Precipitation
- Evaporation
- Runoff
Show answer
Answer: Evaporation
Evaporation converts liquid water into gaseous water vapor. It happens fastest on warm, sunny, windy days when the air can hold more moisture.
The water cycle has a definite beginning and end point.
Show answer
Answer: False
The water cycle is a continuous loop with no start or end. Water keeps moving between Earth's surface and atmosphere in an endless cycle.
Fun facts
- Only about 3% of Earth's water is freshwater, and most of that is frozen in glaciers and ice caps!
- A single large oak tree can release over 40,000 gallons of water into the air through transpiration every year.
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