Chapter 8&9 Flashcards
What are some negatives towards wind power?
- Changes climate and wind speed
- Harms bird and bird migration
- Humans have side effects
How does wind power work?
Wind it’s the rotor which turns the gear box that generates power through the motor
How do solar and thermal energy work?
Heating of water or other energy carrier by concentrated solar heat
- needs really sunny areas
What are solar photovoltaics?
Converting solar energy into electricity with a semi conductor material that absorbs sunlight, which causes the formation of electron-hole pairs
- pairs are separated producing an electric current
Why are sola and wind energy limiting?
Sun is only available during the day
Wind is only good when the days are windy
What is radioactivity?
The spontaneous emission of radiation
What does radiation include?
Alpha particles : nucleus of atom
Beta : fast moving electrons
Gamma rays : carry a lot of energy and move quickly
How are alpha particles created?
Artificially made by ejecting from the nucleus of a larger atom
How are beta particles formed?
Formed when a neutron splits into a proton and an electron in the nucleus
What are gamma particles?
Photons that are high in energy
What is ionizing radiation?
When energy is absorbed it can ionize molecules
When living things absorb it, it can damage the molecules or ionize them
Which is more dangerous; alpha beta or gamma?
Gamma is more dangerous because it can penetrate the the skin easily
- a and b are only dangerous if if emitted when radioactive species is ingested
What is the rate of decomposition expressed as?
Half life
What is nuclear fission?
Splitting of a heavy atom into a lighter one
- large amounts of energy produced
How is nuclear fission initiated?
When neutrons are shot at the nucleus of an atom
What is the most common atom used?
235 Uranium
-nuclei have kinetic energy, evolves into heat
What do the neutrons go on to do?
They can initiate another fission reaction (chain reaction)
Where does the energy come from a nuclear reaction?
When the heavy nucleus is converted to s lighter nuclei some energy is released
What are the components of the energy released during s fission reaction?
Gamma rays and other kinds of radiation
How is the nuclear energy absorbed ?
It is absorbed by the coolant
Why is heating of the coolant important?
It generates steam which turns the turbine to produce energy
Why do we use uranium for nuclear reactions?
The isotope is fissile
What does it mean when an isotope is fissile?
It can sustains fission chain reaction
- each fission can trigger one or more further acts of fission
What are nuclear reactions controlled by?
It slows the reactions and controls the rods that absorb neutrons
What happens when the reaction gets out of control?
The reactors can have a meltdown
- core is melted due to the accumulated heat
Plans for nuclear waste?
For highly radioactive material underground in non-corrosive metal containers
For low radioactive material in a giant warehouses in the same containers with reinforced walls
What is nuclear fusion?
Joining light atoms to produce heavier atoms
Pros of fusion nuclear energy?
- No long term pollution
- Cleaner than fission energy
- Produces tons of energy at high temps ( current tech can’t handle that)
What are 4 pros of fission nuclear energy?
- Produces a lot of energy
- No polluting
- Doesn’t contribute to global warming or acid rain
- Stable source of energy ( unlike solar)
What are cons of nuclear fission?
- Expensive precautions for safety
- Fission products are radioactive
- Not 100% true renewable ( fossil fuels use to extract and transport uranium)
What are some negatives towards hydroelectric?
- Flooding large area of land
- Fish migration
- Displacing human and animal populations
