Evaporation and condensation
🌟 This Topic is About...
- 💧 I will learn about evaporation and condensation.
- 🌬️ I will use the particle model to explain how these changes happen.
- 🔍 I will make predictions and test them through investigations.
- 📈 I will record my results and suggest ways to make my tests better.
- 🌦️ I will learn about the water cycle and even make a model to show it!
Let’s explore how water moves and changes around us! 💧☀️🌈
🌟 Key Words
- condensation
- evaporate
- evaporation
- precipitation
- reverse
- water cycle
📖 Tap to Learn the Meanings!
- 💧 condensation: When water vapour cools down and turns back into liquid drops.
- ☀️ evaporate: When a liquid changes into a gas because of heat.
- 🌬️ evaporation: The process of water turning into vapour and rising into the air.
- 🌧️ precipitation: When water falls from the sky as rain, snow, or hail.
- 🔁 reverse: Doing something in the opposite direction or changing back again.
- 🌎 water cycle: The continuous movement of water between the sky, land, and sea.
Awesome! Now you know the key words for learning about evaporation and condensation! 🌈
💧 Evaporation
When water or other liquids become warm enough, they change into a gas. Water changes into a gas called water vapour. When particles on the surface of a liquid change into a gas, we say the liquid evaporates.
🌞 Where we see it
Evaporation happens all around us without us noticing it much — like a puddle drying up or washing getting dry.
⚛️ What is happening to the particles?
Evaporation happens because some particles in the liquid gain heat energy. The heated particles start to move faster and further apart. Eventually, the heated particles move so far apart that they escape from the surface of the liquid into the surrounding air.
🔍 Let’s Investigate Evaporation!
🤔 Question: Does temperature affect how fast water evaporates?
🧰 You will need: Two identical glasses 🥛, water 💧, a permanent marker 🖊️, a measuring cup or cylinder ⚗️
📝 Method:
- Measure and pour 100 ml of water into both glasses. ⚗️
- Mark the water level on each glass using the permanent marker. 🖊️
- Put one glass in a warm place 🌞 and the other in a cool place ❄️. Leave them for two days.
- Predict what you think will happen and explain why. 🤔
- After two days, mark the new water level in both glasses. 📏
❓ Follow-up Questions:
🌟 Tap to See Answers
- 1: The glass in the warm place lost more water because heat makes evaporation happen faster. 🔥💧
- 2: Higher temperatures give particles more energy to escape as gas. ☀️
- 3: Use the same amount of water, same type of glass, and same time period to keep it fair. ⚖️
Fantastic work, young scientist! 🌈👏
🔎 Think like a scientist — Investigate Evaporation (Continued)
Questions:
- Was the water level in the two glasses the same after two days?
-
a) Which glass had the most water and which glass had the least water after two days? Was your prediction correct?
b) Use the particle model to explain your observations. - Suggest a way you could improve the investigation to find out how much water evaporated from both glasses.
- Why does washing dry quicker on a hot day?
🌟 Show example answers
- 1. No. The levels were different.
- 2a. The warm-place glass had the least water (more evaporated). The cool-place glass had the most. If you predicted this, you were correct.
- 2b. In the warm glass, particles gained more energy, moved faster and further apart. More surface particles escaped into the air (evaporation). In the cool glass, particles had less energy, so fewer escaped.
- 3. Measure the volume or mass lost: start with 100 ml; after two days pour the remaining water into a measuring cylinder and subtract from 100 ml, or weigh each glass before and after and calculate mass lost (≈ water evaporated). Keep other variables the same (same glass, surface area, time, position away from drafts).
- 4. Higher temperature gives water particles more energy so they escape to the air faster; hot days also often have lower humidity and more moving air, which speeds evaporation.
🌫️ Condensation
The air you breathe out is warm and contains water vapour gas. When this warm air touches a cooler surface, such as a mirror, it cools down. If the surface is cold enough, the water vapour turns into tiny drops of liquid water. This process is called condensation.
🔁 Reverse of Evaporation
Condensation is the reverse of evaporation. It happens because the particles of a gas lose energy when they get cooler. As they slow down, they move closer together and change back into a liquid.
🔍 Let’s Investigate Condensation!
🤔 Question: What happens when we put one glass of ice water next to a glass of room-temperature water?
🧰 Equipment: Two identical glasses 🥛, ice 🧊, water 💧, a measuring cup ⚗️, and a cloth 🧽
📝 Method:
- Wipe both glasses clean using a cloth. 🧽
- Fill one glass with water at room temperature and the other with ice water. ❄️
- Leave both glasses for 15 minutes and then observe them carefully. ⏱️
- Make labelled drawings of your observations. ✏️
❓ Questions:
🌟 Tap to See Example Answers
- 1a: The appearance of water droplets on the outside of the cold glass — this is the dependent variable.
- 1b: The type of glass, the amount of water, and the time left — these are controlled variables.
- 1c: The temperature of the water — this is the independent variable.
- 1d: Yes, it’s a fair test because only one variable (temperature) was changed.
- 2: In the cold glass, water vapour particles in the air lose energy and slow down when they touch the cold surface. They move closer together and form liquid water (condensation).
- 3: Condensation is the reverse of evaporation because instead of liquid changing into gas, a gas changes back into liquid when cooled.
Great job exploring condensation, young scientist! 🌈👏
🌊 The Water Cycle
Water keeps moving around our planet in a continuous journey called the water cycle. In this cycle, water travels from the land and sea into the air and then returns again.
🌧️ How the Water Cycle Works
The water cycle happens mainly because of evaporation and condensation. Water from lakes, rivers, and seas evaporates into water vapour and rises into the air. Later, this vapour cools and changes back into liquid water as clouds form.
Freezing and melting can also occur during the water cycle. Rain, snow, and hail that fall from clouds back to the Earth are called precipitation. These processes help to keep water moving endlessly around our planet.
💧 Water Cycle Questions
1a. Where does the heat come from to make water evaporate from rivers, lakes and seas? ☀️
🌟 Show me!
1b. Where else on the drawing does evaporation happen? 🌊
🌟 Show me!
2. Where does the evaporated water go? ☁️
🌟 Show me!
3a. What happens to water vapour when it condenses? 💨➡️💧
🌟 Show me!
3b. Where in the drawing does this happen?
🌟 Show me!
4. How does the evaporated water get back to Earth? 🌧️
🌟 Show me!
5a. Where in the water cycle can freezing happen? 🧊
🌟 Show me!
5b. Where can melting happen? ☀️
🌟 Show me!
6. Complete these sentences using the words in the box. ✍️
🌟 Show me!
b) The water vapour cools and condenses as it rises into the air.
c) Rain, snow and hail are forms of precipitation that bring water back to Earth’s surface. 🌧️❄️👏
7. Why is the water cycle important to us? 🌍
🌟 Show me!
🔍 Let’s Investigate the Water Cycle!
🤔 Question: Can we make a simple model to show how the water cycle works?
🧰 Equipment: A glass or clear plastic bowl 🥣, a small dish 🥄 that fits inside the bowl, water 💧, clear plastic wrap or sheet of clear plastic, an elastic band 🪢, and a small stone 🪨.
📝 Method:
- Place the small dish inside the bowl. 🥣
- Pour some water into the bowl around the dish — about 1 cm deep. Make sure no water splashes into the dish. 💧
- Cover the bowl with plastic wrap and stick it down tightly. You can also use a sheet of clear plastic held in place with an elastic band. 🪢
- Place the small stone on the plastic wrap so it sits over the middle of the dish. 🪨
- Put the bowl in a warm, sunny place and leave it for a few hours. ☀️
- Watch carefully and record what happens! 👀
❓ Questions:
🌟 Tap to See Example Answers
- 1a: Small water droplets formed on the plastic wrap, and some dripped into the small dish. 💧
- 1b: The water in the bowl evaporated, condensed on the plastic, and then fell as drops — just like rain! 🌧️
- 2: The warm sunlight caused evaporation, the cool plastic surface showed condensation, and the drops falling into the dish represented precipitation. ☀️💧🌦️
Fantastic work, young scientist — you just built your own mini water cycle! 🌍👏