Section B: Heat And Temperature

The sun is the earth's main source of heat because it emits large amounts of energy in the form of heat and light. This energy reaches the earth through radiation, warming the planet and sustaining life on it. The sun's heat is essential for various natural processes such as weather patterns, the water cycle, and photosynthesis. Without the sun's heat, the earth would be too cold to support life as we know it.

The Sun is a natural heat source as it emits heat and light through nuclear fusion. Volcanoes are also natural heat sources as they release heat from the Earth's interior through volcanic activity. Geysers, like Old Faithful in Yellowstone National Park, are natural heat sources as they result from underground water being heated by magma, causing it to erupt with hot water and steam.

When the temperature of a solid, liquid, or gas increases, it gains heat. This is because heat is a form of energy transfer from a hotter object to a cooler one. As the temperature rises, the particles within the substance gain more energy and move faster, resulting in an increase in temperature. Therefore, the correct answer is that it gains heat.

Heat is a form of energy that is transferred from a hotter object to a cooler object until both objects reach the same temperature. This is known as the second law of thermodynamics, which states that heat always flows from areas of higher temperature to areas of lower temperature. This process continues until thermal equilibrium is reached, where there is no longer a temperature difference between the objects.

Temperature is not a form of energy. Temperature is a measure of the average kinetic energy of the particles in a substance, while energy refers to the ability to do work or cause a change. Temperature is a property that indicates the degree of hotness or coldness, whereas energy is the capacity to perform tasks or transfer heat. Therefore, temperature and energy are related but not the same thing.

Heat is a form of energy, and the SI unit of energy is the joule (J). Celsius, Fahrenheit, and Kelvin are units of temperature, which is a measure of the average kinetic energy of the particles in a substance.