The sun and moon Flashcards
What is the sun composed of?
75% hydrogen and 25% helium.
What are the advantages of solar energy?
Advantages are that it is renewable and does not emit green house gases
What are the disadvantages of solar energy?
very costly and cannot be used at night or on cloudy days.
Name the 3 technologies that use solar energy.
Passive heating system, photovoltaic cells and solar collectors.
What are solar collectors used for?
Use to capture heat from the sun to heat air and water in buildings, homes, and pools.
What causes tides?
the gravitational field of the moon.
How many times do High tides happen per day?
2 highs and 2 lows.
Advantages of tidal energy
renewable, produces no greenhouse gases and can be predicted.
The disadvantage of tidal energy?
Complex and expensive and can only be built in certain areas.
