Heat: Thermal Energy

How does heat energy travel?

Heat energy travels from objects that are hot to objects that are cold. Sometimes heat energy travels in a wave. This is called thermal radiation. Sometimes heat travels within a fluid. This is called convection.

What kinds of materials allow heat to travel?

Materials called conductors allow heat to travel freely through them. Materials called insulators do not allow heat to travel freely through them.

insulators

Materials that are poor conductors are called insulators. Even the best insulators cannot prevent some heat transfer. Insulators only slow down the heat transfer. Examples of insulators are air, plastic, wood, and glass.

Example of chemical changing to thermal energy

Radiant energy from the sun is converted to thermal energy that warms the Earth and helps support life.

How Does Thermal Energy Affect the Particles That Make up Matter?

When light energy or thermal energy is absorbed by matter, the molecules in the matter vibrate faster. The faster the movement, the more thermal energy the object has. The more thermal energy the object has, the warmer it is to the touch.

radiation

a process by which energetic electromagnetic waves move from one place to another Key Context When you drop a pebble into a pool of water, the water radiates away in circular waves. Similarly, light and thermal energy radiate from the Sun to Earth and electrons in atoms send out X-rays.

radiant energy

energy that does not need matter to travel; light Key Context How can we communicate with astronauts on the space station? Radio waves are electromagnetic waves that exist and are transmitted without matter. They are one form of radiant energy. We can send them back and forth to the space station. Other forms of radiant energy are found in light and x-rays. A hot stove radiates heat energy that you can feel.

conductor

materials that allow heat to travel freely through them are called conductors. Metals, such as copper, iron, and brass, are generally good conductors.

conduction

the transfer of heat energy within an object, or between objects that are directly touching each other, due to collisions between the particles in the objects Key Context When you accidentally touch a hot surface, heat is transferred from the hot surface to your skin in a process called conduction.

convection

the transfer of heat from one place to another caused by movement of molecules Key Context Convection occurs when a pot of water is heated. The hot water rises to the top of the pot, then sinks back down as it cools at the surface. This also happens as hot material rises in Earth's mantle, driving tectonic plate movement in the crust.

How Can Thermal Energy Be Transferred?

there are three ways thermal energy is transferred. The first way is direct contact. which is called conduction. In the process of conduction, the faster vibrating particles in a warmer object make the slower particles of a cooler object vibrate faster. The second way is convection. Convection means Thermal energy can also be transferred through the movement of liquids and gases. The third way thermal energy is transferred is through radiation. Radiation is energy that is carried from one place to another through electromagnetic waves

How Can Thermal Energy Be Produced from Other Forms of Energy?

thermal energy is always produced from another form of energy. Chemical energy, electrical energy, light, and mechanical energy are some forms of energy that can be changed to thermal energy.