P2 | Mindmap

Energy from the Sun.
1. Kinetic energy from moving air turns the blades on a wind turbine to produce electricity.
2. Some gases in the Earth's atmosphere trap heat from the Sun increasing global warming.Scientists disagree about how much effect humans have on the increase in levels of these Greenhouse gases.
3. Passive solar heating uses glass to help keep buildings warm.
4. Photocells do not need fuel or cables,need little maintenance and cause no pollution.
Electricity generation.
1. Power = Voltage x Current.
2. In power stations fuels release energy as heat.Water is heated to produce steam.The steam drives turbines.Turbines turn generators.Generators produce electricity. Efficiency = Output \ Total energy input x 100%.
3. Energy = Power x Time.
  1. Nuclear fuels are radioactive.The radiation produced can cause cancer.Waste products remain radioactive for a long time.
    1. The main forms of ionising radiation are alpha,beta and gamma.Their uses depend on their penetrative and ionisation properties.
4. A dynamo produces electricity when coils of wire rotate inside a magnetic field.The size of the current depends on the number of turns,the strength of the field and the speed of rotation.
5. Transformers change the size of the voltage and current.The National Grid transmits electricity around the country at high voltage and low current.This reduces energy loss.
Our Solar System.
1. Planets,asteroids and comets orbit the Sun in our Solar System.
2. When two planets collide,a new planet and a moon may be formed.
3. Medium-sized stars,such as our Sun,were formed from nebulae and will eventually become red giants,white dwarfs and finally black dwarfs.
The Universe.
1. Scientists believe that the Universe started with a Big Bang.
2. The Universe is explored by telescopes on Earth and in space.Large distances mean that it takes a long time for information to be received and makes inter-galactic travel unlikely.
3. The Universe consists of many galaxies.Models of the Universe have changed over time and sometimes these changes take a long time to be accepted.
4. Most asteroids are between Mars and Jupiter but some pass closer to Earth.They are constantly being monitored.An asteroid strike could cause climate change and species extinction.

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