Science: Human Uses of Energy Flashcards
What are some common fossil fuels that we use today for energy?
Coal, natural gas, petroleum and wood
What is the primary source of almost all fuels? Explain why.
The sun.
The sun makes it possible for living things such as plants and animals to exist on our planet. Once living things die and are underground for a very long period of time, they are eventually turned into fossil fuels such as coal, oil and natural gas. So their original source of stored energy is the sun.
Plants turn energy from the sun into plan materials that store energy, such as wood, which is a type of fuel.
What is chemical energy, and why is it important in our use of energy?
Chemical energy is a type of energy stored in fuel.
We burn fuel to produce energy that meet our needs. In the combustion process, fuel is combined with oxygen to produce heat and light from chemical energy stored in fuel.
Explain: how is energy produced from chemical energy and used in cars?
Combustion in the car engine changes chemical energy in a car’s gasoline into heat. That heat is then used to move engine parts that move the car.
What are the 4 stages of an internal combustion engine? Describe each stage.
1) Intake
- Valve opens and piston lowers to let air and fuel into the combustion chamber
2) Compression
- The piston comes up to compress the fuel and air mixture
3) Power
- A spark ignites the compressed fuel and air mixture, which pushes the piston down to produce motion energy
4) Exhaust
- The piston comes up again, to push out the spent fuel and air out through the exhaust, and the Intake Stage starts all over again
The motion energy could be used to move a car’s wheels, to power the car
Explain: how is energy produced in power plants?
Here is what happens in a coal powered energy plant:
1) In the boiler, coal is burned which changes chemical energy into heat, which boils water to produce hot steam which has a lot of energy.
2) Hot water steam is moved to the turbine, and causes the turbine to spin. (After the water steam moves the turbine, it moves into a cooler, which turns the team back into water.)
3) When the turbine spins, it turns magnets in the generator. When the magnet spins, it produces electric energy in the copper wire coils that surround the magnets.
So, chemical energy from coal goes through a process where it first turns into heat energy, then motion energy, and finally into electrical energy.
Explain: how do batteries produce energy?
A battery stores chemical energy. Chemical reactions in the battery produce electric energy, which can be used to power devices like flashlights, mobile phones and toys.
What are the 6 key parts of a steam engine?
Explain how a steam engine works.
6 key parts:
1) Boiler
2) Combustion
3) Water
4) Steam
5) Exhaust
6) Piston
This is how it works:
1) Fuel (for example coal) is burned in the COMBUSTION chamber, to produce heat.
2) The heat then boils WATER in the BOILER to produce STEAM.
3) Steam passes through the valve and into the PISTON. The hot steam moves the piston. After passing through the piston, the steam escapes through the EXHAUST.
3) The moving piston is connected to flywheels and motors, producing motion energy.
So, like a coal power plant, chemical energy from coal (fuel) goes through a process where it first turns into heat energy and then motion energy. Depending on the device, the motion energy could be used to move something like an old locomotive train, or it could be connected to a generator to further product electrical energy.
How does a generator produce electricity?
Generators take kinetic energy (motion) and converts it into electrical energy. It does this when a source of kinetic energy (for example, when hot steam moves a turbine) spins magnets, which creates an electric current.
Describe the carbon cycle
Carbon is a key building block for all forms of life. The carbon cycle is the circulation of carbon in different forms in nature.
Carbon is found in earth’s atmosphere. Plants absorb carbon from the atmosphere and energy from the sun for photosynthesis to grow.
Plants are then consumed by animals, where carbon is accumulated in the animals’ bodies.
When plants and animals die, they are buried and decompose which, releases their carbon.
Some of the released carbon goes back into the atmosphere to be used again, and some of the carbon eventually turns into fossil fuels.
Fossil fuels are used to power many human activities. When fossil fuels are burned, this releases carbon back into the atmosphere to be used again.
What does non-renewable energy sources mean?
What are disadvantages of using non-renewable energy sources?
Sources of energy that do not replenish naturally. This means that in nature, there are limited sources for this type of energy and may run out with continued use. Examples are coal, gas, natural gas and nuclear energy.
Disadvantages:
- They will eventually run out
- When fossil fuels are burned, they emit gasses that cause pollution, or radioactive residue, which are harmful to the environment and to living beings
- Using fossil fuels also contributes to global warming
True or false: fossil fuels are made from decayed plants and animals over a period of a thousand years.
False. It takes millions of years.
How is coal made?
Hundreds of millions of years ago, earth was swampy. When plants died, they sank to the bottom of swamps, and dead plants built up many layers over a long period of time. They were later covered by soil and rock. Chemical reaction from a combination of compression, decomposition and heat eventually turned them into coal, over 10 millions of years.
True or false: we will eventually run out of coal because coal can no longer be produced naturally.
True.
At the current rate, we will run out of coal in a few hundred years.
How is petroleum made?
Hundreds of millions of years ago, when single cell marine organisms such as algae and plankton died, they fell to the bottom of a body of water. They were eventually covered by sediment. Over a long period of time, through chemical reaction from a combination of compression, decomposition and heat, oil and natural gases were formed.
