1. Science 7: Unit C – Heat and Temperature Topic 7: Sources of Thermal Energy

2. Where do we get thermal energy from? The earliest sources of thermal energy on Earth were the sun (solar energy) and underground vents and volcanoes (geothermal energy). The earliest sources of thermal energy on Earth were the sun (solar energy) and underground vents and volcanoes (geothermal energy). Today we can harness electrical, chemical, wind, and even nuclear power to create thermal energy. Today we can harness electrical, chemical, wind, and even nuclear power to create thermal energy.

3. Chemical Energy Chemical energy was the first type of energy to be used by humans as a source of thermal energy. Chemical energy was the first type of energy to be used by humans as a source of thermal energy. Wood, coal, and other substances all contain chemical energy. Wood, coal, and other substances all contain chemical energy. Any time something is burned for heat, chemical energy is changed into thermal energy. Any time something is burned for heat, chemical energy is changed into thermal energy.

4. Electrical Energy Electrical energy can be changed into thermal energy in a number of appliances: stove-ranges, toasters, space-heaters, etc. Electrical energy can be changed into thermal energy in a number of appliances: stove-ranges, toasters, space-heaters, etc. Electrical energy is produced (NOT CREATED) in a number of ways: Electrical energy is produced (NOT CREATED) in a number of ways: 1. Burning of coal. 1. Burning of coal. 2. Hydroelectric dams (moving water) 2. Hydroelectric dams (moving water)

5. Mechanical Energy Mechanical energy = Energy of motion. Mechanical energy = Energy of motion. When you rub your hands together to generate warmth, you are changing mechanical energy to thermal energy. When you rub your hands together to generate warmth, you are changing mechanical energy to thermal energy. Most examples of mechanical energy involve the moving of an electromagnet turbine. Steam or running water is used to move turbines. This produces a large electric current which is transmitted to homes and businesses. Most examples of mechanical energy involve the moving of an electromagnet turbine. Steam or running water is used to move turbines. This produces a large electric current which is transmitted to homes and businesses.

6. Geothermal Energy Is the thermal energy generated by the hot interior of the Earth. Is the thermal energy generated by the hot interior of the Earth. Ground water is heated even to the point of steam. Ground water is heated even to the point of steam. The hot water/steam can be collected and used by power plants in the turning of their turbines where the moving energy is changed to electrical energy. The hot water/steam can be collected and used by power plants in the turning of their turbines where the moving energy is changed to electrical energy.

7. HDR – Hot, Dry Rock Is a form of geothermal energy. Is a form of geothermal energy. Instead of collecting ground water, water is pumped underground into open rock. The water is heated until it is steam where it rises and is used to generate electricity. Instead of collecting ground water, water is pumped underground into open rock. The water is heated until it is steam where it rises and is used to generate electricity.

8. Solar Energy Solar energy is energy from the sun. This energy includes all forms of EMR, from light radiation to I.R. Solar energy is energy from the sun. This energy includes all forms of EMR, from light radiation to I.R. The upside of solar energy is that the energy is free, and renewable. The upside of solar energy is that the energy is free, and renewable. The downsides of solar energy are that it the technology is still expensive, and the sun doesn’t always shine. The downsides of solar energy are that it the technology is still expensive, and the sun doesn’t always shine.

9. Passive and Active Solar Heating There are two ways to use solar energy as a source of thermal energy. There are two ways to use solar energy as a source of thermal energy. 1. Passive Solar Heating – Energy is absorbed by materials with a high S.H.C. so that the thermal energy is captured and stored. 1. Passive Solar Heating – Energy is absorbed by materials with a high S.H.C. so that the thermal energy is captured and stored. 2. Active Solar Heating – The thermal energy from the sun is absorbed by devices called solar collectors and then moved around the building by fans and other mechanical devices. 2. Active Solar Heating – The thermal energy from the sun is absorbed by devices called solar collectors and then moved around the building by fans and other mechanical devices.

10. Wind Energy Wind energy can be used to produced electricity with a windmill turbine. Wind energy can be used to produced electricity with a windmill turbine. The wind turns the turbine, rotating an electromagnetic generator. The wind turns the turbine, rotating an electromagnetic generator. Many of these windmill generators together are called windmill farms. Many of these windmill generators together are called windmill farms.

11. Biological Energy Warm blooded animals produced heat through the breakdown of sugars. This process is called CELLULAR RESPIRATION. Warm blooded animals produced heat through the breakdown of sugars. This process is called CELLULAR RESPIRATION. Humans can use organisms’ ability to produce thermal energy by having decomposers decompose waste materials in a compost. The breaking down of the waste materials is a chemical change which produces heat. Humans can use organisms’ ability to produce thermal energy by having decomposers decompose waste materials in a compost. The breaking down of the waste materials is a chemical change which produces heat.

12. Fossil Fuels Are chemicals from fossilized plants and animals that have decomposed and hardened over millions of years. Are chemicals from fossilized plants and animals that have decomposed and hardened over millions of years. They usually originate in places that had ancient oceans. Examples include, oil, natural gas and coal. They usually originate in places that had ancient oceans. Examples include, oil, natural gas and coal. Fossil fuels are the main energy resource in Alberta and for most of the world. Fossil fuels are the main energy resource in Alberta and for most of the world.

13. Problems with Fossil Fuels 1. Fossil fuels are a non-renewable resource: This means that they will eventually run out. In fact, we are using fossil fuels at such a high rate, that they are already running out. 1. Fossil fuels are a non-renewable resource: This means that they will eventually run out. In fact, we are using fossil fuels at such a high rate, that they are already running out. 2. The burning of fossil fuels produce greenhouse gases: Greenhouse gases (carbon dioxide) reflect outgoing IR waves back to Earth, heating it up like a greenhouse. 2. The burning of fossil fuels produce greenhouse gases: Greenhouse gases (carbon dioxide) reflect outgoing IR waves back to Earth, heating it up like a greenhouse.

14. Thermal Pollution Is the production of waste heat into the environment from industries, driving your car, furnaces, etc. Is the production of waste heat into the environment from industries, driving your car, furnaces, etc. Cogeneration – is the recycling of this waste heat back into the control system where it can be made to do useful work. Cogeneration – is the recycling of this waste heat back into the control system where it can be made to do useful work.