Every day, we notice things changing from one state to another. This happens because of heat moving around. The main changes we see are melting, freezing, evaporation, and condensation.

Melting and Freezing

• Melting happens when a solid, like ice, gets warm and turns into a liquid. For example, ice will melt at 0°C (32°F).
• Freezing is the opposite. It occurs when a liquid, like water, gets cold and turns into a solid. Water also freezes at 0°C, creating ice.

Evaporation and Condensation

• Evaporation is when liquid water changes into vapor or steam when it gets heat. It can happen at any temperature, but it goes faster when it’s hot. For example, on a warm day around 25°C (77°F), a swimming pool can lose more than 5 liters of water every square meter in a day because of evaporation.

• Condensation happens when water vapor cools down and turns back into liquid. You can see this when dew forms on grass in the morning. This usually occurs when the air is really humid, meaning it can't hold any more water vapor.

Fun Facts

• To melt ice, you need about 334 kJ of energy for every kilogram of ice.
• When turning water into vapor, you need about 2260 kJ of energy for every kilogram of water.

In Sweden, they get about 600 mm of rain each year. This rain plays a big role in evaporation and condensation. It helps shape the local weather and climate.

Everyday Examples

You can see these changes in daily life, such as:

• Boiling water for cooking – you can see steam, which is evaporation.
• Ice cubes melting in your drink – this shows how heat makes ice turn into liquid.
• Dew on grass in the morning – this is an example of condensation from vapor in the air.

By understanding these processes, we learn more about how heat affects our world and daily lives.