What Is Heat Energy?
Heat is a form of energy which is transferred from a substance having a higher temperature to a substance having a lower temperature. The addition of heat to a substance increases its internal temperature. Heat is defined as the net amount of thermal energy of a system.
Heat energy is produced due to the motion of subatomic particles like atoms, ions, and molecules to solids, gases, and liquids. Heat transfer occurs from one system to another system due to the temperature difference between the two systems.
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All forms of matter contain heat energy. No matter if it is a volcano or an ice cube, it has some amount of heat.
Sources of Heat
There are different forms of energy in nature like mechanical energy, sound energy, light energy, electric energy, tidal energy, heat energy, etc. Heat energy is generated due to the transfer of heat from a warm system to a cool system. Heat energy is an essential form of energy in our day-to-day activities like cooking, heating, ironing, etc. An object or system from which heat energy is obtained is called a source of heat energy. Here are some of the major sources of heat energy which are mentioned below:
Sun – The living source of energy
Every second of every day the Sun gives us life generating energy towards Earth, firing our planet with light and life. We cannot always see it. Energy is everywhere you look, it's locked in the atoms giving inside things and it keeps the heart pumping blood through your veins. Energy is the only thing that drives every living things to survive.
Anything that happens from pin drop to an explosion requires energy. Energy is the capacity for doing work. Various forms of energy exist in various forms. The law of conservation of energy states that the total amount of energy in the universe is fixed; it means that energy can only change from one form to another
Earth
The heat energy which is obtained from Earth is called geothermal energy. It can be found in hot water and rocks present underground. Heat is also found in the form of molten rocks and magma, deep inside the Earth's crust.
Air
Air is also an important source of heat energy. It is used for heat pumps for both commercial and residential purposes.
Burning Fuels
Burning of fuels provides heat energy. Fuel is an energy filled combustible substance, which when burnt generates energy. Wood, coal, kerosene, gasoline, petrol, diesel, oil, and charcoal are some common fuels.
Electricity
Electric energy can be converted into heat energy. Iron, water heater, and induction cooker are some of the devices which convert electrical energy into heat energy. This is based on the principle of heating effect of electric current.
How does Heat Energy Get Transferred?
There are three ways for the transfer of heat, and they are mentioned below:
1. Convection- It is a process of heat transfer which occurs due to the actual motion of the particles. It usually occurs in liquids and gases. When air gets heated, it becomes hot and carries heat energy.
Warm air has less density as compared to cool air, hence warm air rises above and cool air descends below to fill the space. This cool air further becomes warm and rises. This process continues and produces convection current.
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2. Conduction- It is the process of heat transfer which occurs due to the vibration of the molecules about their mean position.
Conduction occurs from one part of a system to another part, or in two systems which are in contact with each other. Due to closely packed molecules, solids conduct heat better than liquids and gases.
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3. Radiation- It is a method of heat transfer which uses electromagnetic waves (infrared waves) to transfer heat from one place to the other.
This process does not require any medium to transfer heat. Hot objects radiate out heat waves in all directions at the speed of light. When heat waves strike with an object, it either reflects or absorbs the wave.
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Heat Energy Examples
If the constituent particle of an object becomes excited by gaining energy, the particle moves or vibrates rapidly and the object is said to be hot.
If the particles have less energy, it will not vibrate, and the object is said to be cold. Heat is the transfer of energy between these objects due to a difference in temperature.
Here are some examples of heat energy:
The Sun is the biggest source of heat energy in our solar system. It radiates heat, which reaches Earth in the form of radiation.
A stovetop acts as a source of heat energy when it burns the gas. Anything which is placed above the stove also becomes a source of energy to cook things.
Automobile fuels are also a source of heat energy. When the fuel burns, it provides energy for the motion of the vehicle.
A hot cup of tea or coffee contains heat energy.
When you hold a piece of ice in your palm, the heat energy from your hand melts the ice.
A radiator, heating system, or a room heater provides the necessary radiant heat energy to warm your house during the winter season.
Conventional oven is a source of convection heat energy; the food becomes hot when it is placed in it.
Various Forms of Energy
Energy exists in many different forms. Examples of these are as follows:
light energy,
heat energy,
mechanical energy,
gravitational energy,
electrical energy,
sound energy,
chemical energy,
nuclear or atomic energy, and so on.
Each form can be converted or changed into the other forms.
Transformation of Energy
All the energy forms follow a universal law known as law of conservation of energy which states that energy can neither be created nor destroyed but can be altered from one form to the another. This implies that all forms of energy are interconvertible. The process of changing one form of energy into another is called an energy transformation.
Examples of of Converting Energy
Consider a ball falling from the top of the floor of a building. Initially, it has potential energy stored. Due to its height as the ball falls, the potential energy changes to kinetic energy.
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Charging of batteries converts electrical energy to chemical energy and chemical to electrical.
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Conversion of chemical energy in the form of petrol converting into heat energy and finally into kinetic energy.
Importance of Heat Energy
In physical science, heat is essential, especially for plants and animals. Plant life depends on heat, among other things, to survive as well. Heat is a result of energy, which can be beneficial as well as dangerous.
FAQs on Heat Energy
1. What are some uses of heat energy?
Some uses of heat energy are mentioned below:
Thermometers use heat energy to measure temperature.
Heat energy is necessary for the existence of life on Earth.
The steam thermal power plant uses heat energy to heat the air, and water present in air is also heated.
Sweater uses heat energy to keep the body warm, by trapping heat between its layers.
Heat energy melts helps the fuse wire, in fuses, thus preventing any damage to electric circuits.
Heat energy is used for medication in heat therapy to cure muscle strains.
2. How is heat produced?
Heat is produced by various sources.
The heat energy of the Sun is generated due to the fusion of its hydrogen and helium atoms. This energy is then radiated out from the surface of the Sun.
The heat energy of a fire is generated due to the combustion of fuel or other materials.
The heat energy of an electric appliance is generated due to the friction of electrons with the resisting elements.
Heat is produced in our body due to the chemical and biological reactions that occur within the cells.
Heat is also produced due to the vibration of the molecules or atoms.
3. What is the use of energy in the world?
The world population has grown and we have invented petrol-guzzling cars and built feel hungry homes. Our energy needs have increased; the total worldwide energy use has increased by about 14 times since the early 20th century.
4. What are other alternative sources of energy?
The alternative sources of energy are as follows:
Solar energy from the Sun
Wind energy
Geothermal Energy
Hydropower from flowing water
Ocean energy in the form of wave, tidal, current energy, and ocean thermal energy
Biomass from plants.
5. How can heat energy be transformed into other forms of energy?
Heat can also be converted to and from other forms of energy.
For example:
Coal in thermal plants is converted into electricity.
When cooking food, heat energy is converted into mechanical energy.
The heat of sunlight is converted into solar energy.
