Thermal energy facts for kids
Thermal energy is a term used in physics and engineering to describe different ideas about energy. It can mean the total energy inside something (called internal energy), or it can refer to heat, which is a type of energy that moves from one place to another. It can also describe the energy of tiny particles inside a system, which is linked to its temperature.
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What is Thermal Energy?
In science, heat is energy that moves into or out of a system. This happens through things like conduction (touching), radiation (like from the sun), or friction. Heat is about energy moving, not about energy being stored inside something. Think of it like water flowing from one bucket to another, not the water already in a bucket.
On the other hand, internal energy is the total energy stored inside a system. It's like the water already in the bucket. Heat and work are ways energy moves, but internal energy is what the system has at a certain moment, no matter how it got there.
Energy from Chemical Changes
Sometimes, energy stored in chemicals (called chemical potential energy) can change into other forms of energy. When this happens, we often say it becomes "thermal energy." This thermal energy can add to the total internal energy of a substance. It's like when you burn wood; the chemical energy in the wood turns into heat and light. We call this the "heat of reaction."
Thermal energy can also describe the energy that flows as heat. So, when heat moves from a hot object to a cold one, that moving energy is also called thermal energy.
Energy of Tiny Particles
Imagine a gas where tiny molecules are constantly moving and bumping into each other. The total energy of all these moving particles is their kinetic energy. This kinetic energy is what we often call "thermal energy" at a very small, microscopic level. It's also what causes heat to transfer.
In many science books, "thermal energy" can also mean a very specific amount of energy: `kT`. This is the Boltzmann constant (`k`) multiplied by the absolute temperature (`T`). It helps us understand the average energy of individual particles in a system.
In liquids or solids, particles are packed closer and interact more strongly. Their interactions also add to the internal energy, making it a bit more complex than just the movement of particles.
How We Learned About Thermal Energy
In 1847, a scientist named James Prescott Joule gave a famous talk about energy, force, and heat. He helped us understand different types of heat.
- Latent heat is energy that changes the state of something, like turning ice into water, without changing its temperature. Joule saw this as energy related to how particles are arranged (like potential energy).
- Sensible heat is the energy that makes something hotter, which you can feel and measure with a thermometer. Joule called this the "living force" of particles, meaning their movement (like kinetic energy).
Thermal Energy Projects
Australia
In Australia, there's a project called the MGA Thermal Energy Storage Project. It's working on a large system to store thermal energy using a special material. This system can store heat and release it later, which is useful for energy grids.
See also
- Geothermal energy
- Heat transfer
- Ocean thermal energy conversion
- Thermal energy storage
