nviz revision

Here are the answers to the revision sheet if you want to check yours:

Q1. television - d
       Speakers - b
       Spark - e
       Digger - c
       Kettle - a

Q2. a-If the television were more efficient, less heat would be produced as this is wasted energy.
       b-Energy going in, coming out as sound and heat.  Something like the picture below but with sound and heat labelled instead of 'useful work' and 'heating the surroundings.'

Q3. The atmosphere is a layer of gases which surrounds the earth.  By produing more carbon dioxide and releasing it into the atmosphere, we allow the Earth to warm up.  This is called the greenhouse effect and leads to global warming and climate change.
Q4. Renewable energy sources, such as solar, wind and hydroelectric power produce no carbon dioxide while producing electricity.  This will decrease the rate of climate change and prepare us for wen fossil fuels run out.
Q5. Wind and solar power only provide electricity when it is sunny or windy.  This means that they can not be available at times when they are needed.  To fix this this problem, either a battery to store power is needed, or another renewable energy source that provides constant energy, like geothermal or hydroelectric power.
Q6.  Climate change may cause Sea levels to rise, Ocean acidification, increased frequency and severity of extreme weather (storms, hurricanes), droughts, diseases and food shortages.  These problems could lead to many social and other problems.