Last week we learned that water moves in a never-ending loop around our planet. This week we are going to study each stage of the water cycle in detail. Understanding each step helps us predict the weather, explain why plants grow, and understand where rain comes from. The water cycle is one of the most important natural processes on Earth because it moves water from the oceans to the land and back again.
Evaporation is the first major step. When the sun warms water in oceans, lakes, and rivers, the water changes from a liquid into an invisible gas called water vapor. This water vapor rises into the air. You can see evaporation happening when a puddle disappears after a sunny day or when wet clothes dry on a line. Plants also release water vapor through their leaves in a process called transpiration, which adds more water vapor to the air.
Condensation happens next. As water vapor rises higher into the sky, the air gets cooler. The cool air causes water vapor to change back into tiny liquid water droplets. These droplets are so small and light that they float in the air, forming clouds. You can see condensation in everyday life when water droplets form on the outside of a cold drink glass or when fog covers a field in the morning. Clouds are basically huge collections of billions of tiny water droplets floating together.
Precipitation is the third step. When enough water droplets collect in a cloud, they combine to become larger and heavier. Eventually they become too heavy to stay floating in the air, so they fall back to Earth. The type of precipitation depends on how cold the air is. When the air is warm, water falls as rain. When the air is below freezing, water falls as snow. Sleet is rain that freezes into ice pellets as it falls through cold air. Hail forms inside storm clouds when water freezes into balls of ice that bounce up and down, growing larger with each trip.
1. What causes evaporation?
2. Give two everyday examples of condensation that you might see at home.
3. What determines whether precipitation falls as rain or snow?
4. Describe the complete journey of a drop of water from the ocean to a cloud to the ground and back to the ocean.
Write a definition or draw a picture for each word.
Sort each type of precipitation into the correct column: warm weather or cold weather.
| Precipitation Type | Warm Weather | Cold Weather |
|---|---|---|
| Rain | ||
| Snow | ||
| Sleet | ||
| Hail |
Fill in the chart describing each type of precipitation.
| Type | What It Is | When It Falls | What It Looks Like |
|---|---|---|---|
| Rain | |||
| Snow | |||
| Sleet | |||
| Hail |
Read each situation. Write E for evaporation or C for condensation.
| Situation | E or C? |
|---|---|
| A puddle on the sidewalk dries up after a sunny day. | |
| Water droplets form on a cold juice box. | |
| Clouds form in the sky after a warm day. | |
| Wet hair dries after you take a shower. | |
| Fog appears over a lake in the morning. | |
| Steam rises from a hot cup of cocoa. | |
| Your mirror fogs up during a hot bath. | |
| An ocean wave disappears as a mist on a warm beach. |
1. Evaporation turns liquid water into invisible water vapor.
2. Condensation happens when water vapor heats up.
3. Clouds are made of tiny liquid water droplets.
4. Precipitation only falls as rain.
5. Transpiration is when plants release water vapor.
6. Snow falls when the air is above freezing.
7. Hail forms inside storm clouds.
8. Sleet is rain that freezes into ice pellets while falling.
Word Bank: evaporationcondensationprecipitationwater vaportranspirationsnowhailsleet
1. When the sun heats water and it turns into gas, that is ________________.
2. The invisible gas that rises into the air is called ________________.
3. When water vapor cools and forms clouds, that is ________________.
4. Water falling from clouds is called ________________.
5. When plants release water through their leaves, it is called ________________.
6. Frozen precipitation that falls as ice crystals is called ________________.
7. Balls of ice that form in storm clouds are called ________________.
8. Rain that freezes into ice pellets while falling is called ________________.
Think about a cold day when you go outside from a warm house. Why do you see your breath? Which water cycle stage is that an example of? Explain.