Science revision Notes Year 8 AQA end of topic test

earth's atmosphere 

atmosphere = the thin layer of gas around the earth that lets in heat from the sun and reflects some of it back outside of the atmosphere so that the planet doesn't get too hot while letting in some of the heat so that the planet doesn't get too hot.

the highest percentages of components in the atmosphere are nitrogen and oxygen

the carbon cycle:

-shows how carbon is used and stored on the earth

-it is being affected by humans because more and more fossil fuels are being extracted which causes lots of carbon to be produced as a waste product and is causing the decrease in the amount of fossil fuels, there are less plants to carry out the process of photosynthesis which means that there is more carbon dioxide as a result and there are less animals and living things because of habitiat destruction, hunting etc which means less carbon dioxide in the air

- we do need some carbon dioxide in the air but too much will cause the planet…