Acid rain is made by air pollution. When fuel is burnt, lots of different chemicals are made. The smoke that comes from a fire or the fumes that come out from a car exhaust don't just contain the sooty grey particles that you can see - they also contain lots of invisible gasses that can be even more harmful to our enviroment. Power stations, factories and cars all burn fuels and therefore they all produce polluting gases. Some of these gases (especially nitrogen oxides and sulphur dioxide) react with the tiny droplets of water in clouds to form sulphuric and nitric acids. The rain from these clouds then falls as very weak acid - which is why it is known as "acid rain". this information came from http://www.yptenc.org.uk/docs/factsheets/env_facts/acid_rain.html

This is what will happen to your umbrella when it's raining acid this picture is from http://www.pnuma.org/bienal/album/images/Acid%20rainPNUMA_tif.jpg

Acidity is measured using a scale called the pH scale. This scale goes from 0 to 14. 0 is the most acidic and 14 is the most alkaline (opposite of acidic). Something with a pH value of 7, we call neutral, this means that it is neither acidic nor alkaline. Very strong acids will burn if they touch your skin and can even destroy metals. Acid rain is much, much weaker than this, never acidic enough to burn your skin.Rain is always slightly acidic because it mixes with naturally occurring oxides in the air. Unpolluted rain would have a pH value of between 5 and 6. When the air becomes more polluted with nitrogen oxides and sulphur dioxide the acidity can increase to a pH value of 4. Some rain has even been recorded as being pH2.Vinegar has a pH value of 2.2 and lemon juice has a value of pH2.3. Even the strongest recorded acid rain is only about as acidic as lemon juice or vinegar and we know that these don't harm us - so why do we worry about acid rain? this information came from http://www.yptenc.org.uk/docs/factsheets/env_facts/acid_rain.html

see if you can spot acid rain this picture came from http://www.virtualsciencefair.org/2005/edgc5c0/public_html/phscale.gif

Acid rain can be carried great distances in the atmosphere, not just between countries but also from continent to continent. The acid can also take the form of snow, mists and dry dusts. The rain sometimes falls many miles from the source of pollution but wherever it falls it can have a serious effect on soil, trees, buildings and water. Forests all over the world are dying, fish are dying. In Scandinavia there are dead lakes, which are crystal clear and contain no living creatures or plant life. Many of Britain's freshwater fish are threatened, there have been reports of deformed fish being hatched. This leads to fish-eating birds and animals being affected also. Is acid rain responsible for all this? Scientists have been doing a lot of research into how acid rain affects the environment. this information came from http://www.yptenc.org.uk/docs/factsheets/env_facts/acid_rain.html

this picture is from http://www.fish.state.pa.us/anglerboater/2001/jf2001/acidrainf.jpg