topic 8 - earth and atmospheric science

describe how the earth’s early atmosphere was produced

describe how the earth’s early atmosphere was produced

• by gases

• formed by volcanic activity

describe what the earth’s early atmosphere was thought to contain

• little or no oxygen

• large volume of carbon dioxide

• water vapour

• small volumes of other gases

explain how condensation of water vapour formed oceans

• as the earth cooled, water vapour in the atmosphere condensed into liquid water

• this water fell as rain to form oceans

explain how the amount of carbon dioxide in the atmosphere was decreased when carbon dioxide dissolved as the oceans formed

• carbon dioxide is a soluble gas

• it dissolves easily in water

• as more oceans were formed, there was more water for the carbon dioxide to dissolve in

• as more dissolving was occurring, the amount of carbon dioxide in the atmosphere went down

explain how the growth of primitive plants gradually increased the amount of oxygen in the atmosphere

• primitive plants used photosynthesis

• photosynthesis uses carbon dioxide as a reactant with water to produce oxygen and glucose

• as more plants completed photosynthesis reactions, more oxygen was being released into the atmosphere

describe the chemical test for oxygen

1. place a glowing splint in a test tube containing a gas

2. if the splint relights, the gas is oxygen

describe the composition of earth’s modern atmosphere

• 78% nitrogen

• 21% oxygen

• 1% argon

• 0.93% carbon dioxide

• 0.035% water vapour/other gases

describe the potential effects on the climate of burning fossil fuels

• burning fossil fuels releases carbon dioxide into the atmosphere

• carbon dioxide enhances the greenhouse effect

• which is where greenhouse gases absorb heat from the earth and re-emit back to earth

describe the potential effects on the climate of livestock farming

• livestock produce excess methane through gas

• this enhances the greenhouse effect as it increases the amount of greenhouse gases in the air

• which increases the rate of absorption and re-emitting of heat

• to get the space for livestock farming, trees need to be cut down

• trees take in carbon dioxide and release oxygen

• this increases the amount of carbon dioxide in the atmosphere

• which enhances the greenhouse effect

explain how to mitigate the effects of burning fossil fuels and livestock farming on the climate

GLOBALLY:

• opt for renewable energy sources such as wind and solar

INDEPENDENTLY

• eat less meat every week as this decreases demand for supply

explain what the greenhouse effect is