Heat energy is very important for how different types of matter behave. Matter mainly comes in three states: solids, liquids, and gases. Each state has its own unique features based on how energetic or mobile its particles are.

1. Melting and Freezing

• Melting: When a solid gains heat energy, it gets warmer and eventually reaches a temperature called the melting point. For example, ice melts when it hits 0°C (32°F). The heat energy that ice absorbs to melt is about 334 joules for every gram of ice.

• Freezing: On the other hand, when a liquid loses heat energy, it cools down and will eventually freeze at its freezing point, which is also 0°C for water. The energy released during freezing is the same as the energy it took to melt.

2. Evaporation and Condensation

• Evaporation: A liquid can turn into a gas when it absorbs heat energy. Water can evaporate at any temperature, but it happens faster when it's warm. The energy needed for water to evaporate is around 2260 joules for every gram.

• Condensation: When a gas cools down, it releases heat energy and turns back into a liquid. The energy released during this process is the same amount of energy that the gas absorbed when it evaporated.

3. Sublimation

• Sublimation: Some materials, like dry ice, can go straight from solid to gas without becoming a liquid first. This process occurs when they absorb heat and requires about 573 joules for every gram of dry ice.

Understanding how heat energy works with different states of matter is very important for learning about temperature changes in physics.