FutureStepsA quick starting check.
- Recognize liquid water, solid ice and water vapor as forms of water.
- Distinguish a change of state from water disappearing.
- Know that sunlight transfers energy and gravity pulls objects toward Earth.
Build the method, one step at a time.
Evaporation puts water vapor into the air
Evaporation is a change from liquid water to water vapor, a gas. The Sun provides energy that helps water evaporate from lakes, oceans, puddles and other surfaces. Water can evaporate without boiling.
Water vapor is invisible. When a puddle gets smaller through evaporation, some of its water has entered the air. Other processes, such as soaking into the soil, can also make a puddle smaller, so a real observation may have more than one cause.
Condensation forms liquid droplets
When air containing water vapor cools enough, some vapor can condense into liquid droplets. Clouds contain tiny liquid droplets, ice crystals or both. A visible cloud is not simply a collection of invisible water vapor.
Condensation also happens near the ground. If water droplets form on the outside of a cold glass, water vapor from the surrounding air has condensed on the cool surface. The droplets need not have leaked through the glass.
Precipitation and gravity return water to the surface
Cloud droplets and ice particles can grow large enough to fall as precipitation, including rain or snow. Gravity pulls falling water toward Earth. Sunlight supplies energy for evaporation; it does not pull rain downward.
Water can collect in a lake, flow over land, soak into soil or remain stored as ice. Plants also release water vapor from their leaves. The water cycle has no single starting point or fixed route: water can take many paths and spend very different amounts of time in each place.
Two worked examples.
Follow one possible route from a lake to rain
- Sunlight transfers energy to the lake. Some liquid water evaporates and becomes water vapor in the air.
- Air carrying that vapor rises and cools enough for some water to condense into tiny droplets. Those droplets can contribute to a cloud.
- Some droplets grow and fall as rain. Gravity pulls them downward; some of the rain may flow back into the lake.
Check your reasoning: This is one possible route, not a timetable for every drop. The water remains water through evaporation and condensation.
Explain droplets on a cold glass
- Imagine a dry glass containing cold water in a room with moist air. After a while, droplets appear on the outside.
- The outside surface cools nearby air enough for some water vapor to condense. The droplets are liquid water from the surrounding air.
- Connect the observation to cloud formation: both involve water vapor condensing, although a glass surface and a cloud are different settings.
Check your reasoning: The outside droplets do not prove the glass leaks. Condensation provides an explanation even when the glass has no opening or crack.
Try it before you reveal it.
Write down your thinking. Open a hint if you get stuck, then compare your method with the explanation.
Practice 1
Liquid water on a wet pavement changes into water vapor in the air. What process is this?
Show a hint
Name the change from liquid to gas.
Show the answer and explanation
Evaporation.
The water changes state and enters the air. It has not vanished or become a different substance, and the pavement does not need to reach boiling temperature.
Practice 2
Moist air cools enough and tiny liquid droplets form. Is this evaporation, condensation or precipitation?
Show a hint
Start with water vapor and follow the change into liquid.
Show the answer and explanation
Condensation.
Condensation changes water vapor into liquid droplets. Precipitation describes water falling from clouds, while evaporation changes liquid into vapor.
Practice 3
What different jobs do the Sun and gravity have in the lake-to-rain example?
Show a hint
Separate the energy for a state change from the pull on falling rain.
Show the answer and explanation
The Sun supplies energy for evaporation; gravity pulls falling rain toward Earth.
Both help explain movement in the cycle, but they play different roles. Water that reaches the surface may then collect, flow or soak into the ground.
What to take with you.
Track both the water’s state and its location. Evaporation, condensation and precipitation describe different processes within a cycle that has many paths.
Try explaining one example without looking at the steps. If a step is hard to explain, revisit that part before moving on.
Give me one everyday water observation at a time. Ask me to identify the state change and explain where the water came from or went.
Eligible students ages 13 and older with Study access can sign in and use this prompt for more practice. Check AI explanations against your class materials.
Continue in StudyWritten by FutureSteps for study and review. This lesson expands a topic in our Texas starter collection. Course reference: Texas TEKS · Grade 4 Science (§112.6(b)(10)(A)). These references do not imply endorsement, complete standard coverage or assessed mastery. Follow your school’s materials and course sequence.
Explore more in the 4th grade learning guide.