How Does Water Evaporate?
Do you want to learn faster and more easily?
Learning text on the topic How Does Water Evaporate?
Water Evaporation – Definition
Evaporation is the process where water changes from a liquid to a gas. This happens when water molecules get enough energy to break free from the surface of the liquid and turn into water vapour. We see evaporation in everyday life when puddles dry up or wet clothes dry in the sun.
Evaporation is when water changes from a liquid to a gas.
Understanding Water Evaporation – Explanation
Evaporation is an essential part of the water cycle. The sun heats up water in rivers, lakes and oceans, causing the water to evaporate and become water vapour. This water vapour rises into the sky and cools down, turning back into liquid water to form clouds. This process is called condensation. When the water droplets in clouds become heavy, they fall back to the ground as rain, completing the water cycle.
Boiling Point
Water also turns into gas quickly when it reaches its boiling point. The boiling point of water is 100 degrees Celsius (100°C). When water boils, it changes from liquid to gas rapidly, forming steam.
Water Evaporation – Example
Let’s explore an example to understand evaporation better.
Observing Evaporation
Place a small bowl of water in a sunny spot and another bowl in a shady spot. Over time, you will notice that the water in the sunny spot evaporates faster than the water in the shade. This is because the sun's heat gives more energy to the water molecules, helping them evaporate quicker. Test your knowledge further with these water experiments.
Factors Influencing Evaporation
| Factor | Description | Effect on Evaporation |
|---|---|---|
| Temperature | Higher temperatures increase energy in water molecules | Increases evaporation speed |
| Surface Area | Larger surface area exposes more water to air | Increases evaporation speed |
| Air Movement | Wind moves water molecules away from surface | Increases evaporation speed |
| Humidity | More water vapour in the air | Decreases evaporation speed |
Understanding Evaporation – Exercises
Water Evaporation – Summary
Key Learnings from this Text:
- Evaporation: Water changes from liquid to gas.
- Factors affecting evaporation: Temperature, surface area, air movement and humidity.
- Boiling point: Water boils at 100 degrees Celsius (100°C).
- Condensation: Water vapour turns back into liquid, forming clouds.
By understanding these concepts, you can appreciate the role of evaporation in the water cycle and its impact on our environment.
Frequently Asked Questions – Water Evaporation
How Does Water Evaporate? exercise
-
Can you figure out the process?
HintsThe main reason this process happens is because of heat.
Imagine having a sponge that is wet in your hand. What happens to the water on the sponge when you leave it outside in the sun?
SolutionThe process that occurs when water slowly changes from a liquid to a gas without boiling is called evaporation.
-
Do you know what vaporisation is?
HintsThe boiling point of water is 100 degrees celcius.
Vaporisation happens when a liquid is heated to its boiling point.
SolutionThese are the correct answers:
- When water is heated to a temperature of 100 degrees Celsius, it boils.
- During vaporisation, water changes from a liquid to a gas as a result of being boiled directly with a heat source.
- If the water boils and is vaporised, it is only invisible for a short time.
-
When does condensation happen?
HintsCondensation is the opposite of evaporation.
Condensation happens when water vapour in the air cools down.
Solution- When the water vapour touches the colder air, it goes through a process called condensation.
- When water boils, this creates tiny water droplets that rise to the surface.
-
What affects the speed of evaporation?
HintsEvaporation is slower on humid days.
Windy days can help evaporation happen faster.
More water is exposed to the air in a big puddle, so more of it can turn into vapour.
SolutionThere are different factors that affect the speed of evaporation.
For example:
- The temperature: Evaporation is faster when it's warm and sunny outside.
- The surface: If water is spread out in a large puddle, it will evaporate faster than if it is placed in a small puddle.
- Air movement: When the wind blows, it takes away the water vapour, making more room for new water molecules to evaporate from the surface.
- The humidity: If the air is already full of water, it's harder for more water to evaporate into it.
-
Can you recognise the processes happening?
HintsImagine water in a puddle or on your clothes drying up and disappearing.
The water evaporates because of the Sun's heat.
Vaporisation means both evaporation and boiling.
Picture a window on a chilly morning. When warm breath turns into tiny droplets, you're witnessing a process called condensation.
SolutionThe correct answers are:
- Evaporation happens when water turns into water vapour.
- Vaporisation happens when boiled water turns into water vapour.
- Condensation happens when water vapour touches the colder air.
-
Understanding water processes.
HintsThe heat from the Sun gives the water more energy, and some of the water turns into invisible vapour and goes up into the air.
This process is called evaporation.
Have you ever noticed how your bathroom mirror gets all foggy and covered in tiny water droplets after you take a nice, warm shower?
The mirror is much colder than the warm air from the shower. So, when the warm air reaches the mirror, it cools down quickly.
This process is called condensation.
Solution- The sun shines down on a puddle, whisps of vapour can be seen escaping upwards from the puddle. This is evaporation.
- After a hot shower, drops of water appear on the bathroom mirror. This is condensation.
- The kettle boils and bubbles of water can be seen rising and popping near the surface. This is vaporisation.
- Hot food is left in a lunchbox. Steam rises up and hits the lid. Tiny water droplets appear on the inside of the lid. This is evaporation and condensation.
