What are the 4 advantages of photocells?

What is the only disadvantage of photocells?

What do photocells contain?

Which has an impurity added to produce an excess of free electrons and which one has an impurity added to produce an absence of free electrons?

What does sunlight contain?

What do photons cause?

What are the 3 things that the output from a photocell depends on?

How does passive solar heating work?

How are solar reflectors so efficient?

When do wind turbines not work?

What are the advantages and disadvantages of wind farms?

What are the 3 ways in which the current from a dynamo can be increased?

What does an oscilloscope do?

What is the time for one complete cycle called?

What does a simple generator consist of?

Where are the structure of simple generators used?

How do conventional power stations work?

Why are power stations not very energy efficient?

What type of radiation is absorbed by the earth's atmosphere?

What are the 5 things that produce carbon dioxide?

What are the 4 man made things that produce carbon dioxide?

3 facts about water vapour

When is methane produced and give 2 examples of this

Explain the greenhouse effect

What does smoke from factories do?

What does the ash cloud from volcanoes do?

What do scientists agree on to do with global warming?

What do scientists disagree on to do with global warming?

When do we pay less for electricity?

What are the 4 things that the choice of energy source depends on?

What is the National grid?

What does the high voltage lead to? (3 things)

What are used to step down the voltage to a more suitable level for the consumer?

Why is a higher voltage used?

What does ionisation involve?

What can the formation of ions cause in the body?

Where do alpha, beta and gamma radiations come from?

Which causes the most ionisation?

What is alpha radiation's range and what does this cause to happen?

What is beta radiation's range and what does this cause to happen?

What is gamma radiation's range and what does this cause to happen?

How do smoke alarms use radiation to detect smoke?

How can radiation be used to control the thickness of paper?

What can gamma radiation be used for?

What can the passage of blood around the body be detected using?

What is plutonium?

How do you dispose of low level and high level radioactive waste?

Why is the storage and disposal of radioactive waste very important?

What are the two advantages of using nuclear power stations?

What are the three disadvantages of using nuclear power stations?

What types of orbits do comets have?

What are meteors made out of?

What are black holes?

Why do moons orbit planets?

What can we send up to explore space?

What do spacecraft carrying humans have to have a lot of?

What are the 4 things that an astronauts suit has to do?

Why are unmanned spacecraft often better?

How fast does light travel?

How long does light take to reach the earth from the sun?

How much does it cost to fly to Mars (according to America's planned trip)?

What are asteroids?

What caused all bodies in space to be created?

What determines something's gravitational force?

What prevents asteroids from joining together to form another planet?

How do scientists think the moon was made?

What are the 3 pieces of evidence that support the theory of how the moon was created?

What are the 3 pieces of evidence that support the theory that asteroids have collided with the Earth?

Where do most comets pass?

What happens as the comet passes close to the sun?

What are scientists constantly tracking?

Why does the speed of a comet increase as it approaches the sun and decrease as it gets further away?

What shape is a comets orbit?

What happens if an NEO is heading for earth?

In what way is the universe expanding?

How did Galileo's observations help support Copernicus' ideas?

Why didn't the Roman Catholic Church support Galileo's model?

What was Newton working on in the 17th century?

Why do we believe that the gravitational collapse of the universe is prevented?

What is red shift?

What is the difference between the light pattern observed form the sun and from a distant star?

What can scientists use red shift to find out?

What is the swirling cloud of gas and dust?

Explain a star's life

Why do small stars shine for longer than large stars?

How does a medium stars life end (like the sun)?

How does a large star's life end?

What can happen in the aftermath of a supernova?

What are the properties of a black hole?