Properties of water
🌊 This Topic is About...
- 💧 I will investigate the amazing properties of water.
- 🌍 I will learn that most water on Earth has other substances dissolved in it.
- 🌡️ I will measure temperature carefully during experiments.
- 🦺 I will learn how to spot safety risks and work safely in investigations.
- 📊 I will record my measurements neatly in a table.
- 📈 I will draw line graphs to show my results clearly.
- 🔍 I will find and use information to answer a scientific question.
Let’s dive into the world of water and discover its secrets! 💦🔬
🌟 Key Words
- boil
- boiling point
- contract
- expand
- melt
- melting point
- steam
- temperature
- thermometer
📖 Tap to Learn the Meanings!
- 🔥 boil: When a liquid gets so hot it turns into a gas, like water into steam.
- 💧 boiling point: The temperature when a liquid starts to boil.
- ⬇️ contract: When something gets smaller or shorter, often when it cools.
- ⬆️ expand: When something gets bigger, often when it gets hotter.
- 🧊 melt: When a solid changes into a liquid, like ice turning into water.
- 🌡️ melting point: The temperature when a solid starts to melt.
- 💨 steam: Hot water vapour that you can see when water boils.
- 🌞 temperature: How hot or cold something is.
- 🧪 thermometer: A tool used to measure temperature.
Great job learning your science words about heat and water! 💦🔥
💧 Water changes state
Solids, liquids and gases are different states of matter. Water exists in all three states of matter. Ice is solid water. The water we drink is a liquid. Water vapour in the air is a gas.
🔥 Heating and melting
Water changes state when it is heated or cooled. For example, when we heat ice, it melts to form liquid water.
🧊 What melting means (particle view)
When solids, like ice, are heated, their particles gain energy and start to move more quickly and pull further apart. If the particles gain enough energy, they move far enough apart that the solid becomes a liquid. We can show melting like this.
💨 Boiling and steam
If we heat water enough, it will boil. When water boils it forms bubbles of a gas called steam (heated water vapour). The liquid’s particles gain energy, move much faster, and some move far apart to become a gas. This happens throughout the liquid, not just at the surface. We can show boiling like this
🌡️ Melting and boiling points
All substances melt and boil. Different substances take different times to melt or boil because it takes different amounts of heat for them to change state. The amount of heat in a substance is called its temperature. We measure temperature with a thermometer. The unit we use is degrees Celsius (°C).
The boiling point of pure water
BPure water freezes at 0°C, but most of our water has small amounts of other substances mixed with it. This makes the water boil at a slightly different temperature. Water also boils at a lower temperature the higher we are above sea level.
Heated particles move faster
Heated particles move faster and further apart. The cooled particles move more slowly and closer together.
Water Expands
We know from the particle model of matter that when a substance gains heat its particles move faster and spread out. This makes the substance take up more space. We say that the substance expands. When the substance cools down, its particles move more slowly because they have less energy and move closer together. The cooled substance takes up less space. It gets smaller, or contracts.
Boiling and Freezing Points of Water
BThe boiling point of pure water is 100°C, but most of our water has small amounts of other substances mixed with it. This makes the water boil at a slightly different temperature. Water also boils at a lower temperature the higher we are above sea level. Water freezes when the temperature drops to 0°C.
Water's Unique Behavior
Water does not always behave like other substances. When we freeze or solidify water, it does not contract as we would expect. Instead, it expands. This property of water also allows ice to float.