aka...science room
plants
You owe your existence to plants. Without them there would be no food and no oxygen, which means no life as we know it.
A pot plant grows - if you remember to water it - but the soil does not get used up. So where is all the plant coming from – thin air?
Photosynthesis
Amazingly, yes. Plants take carbon dioxide from the air and combine it with water to produce glucose. This needs energy – and plants get it free from the Sun.
Sunlight is absorbed by chlorophyll, a pigment responsible for the green colour of leaves. Chlorophyll is contained in chloroplasts and together they make leaves the most efficient solar panels on Earth. The most wondrous thing about photosynthesis is that water molecules are split using sunlight - something that only plants can do. This stage of photosynthesis is called the light reaction, for obvious reasons! The oxygen released is a waste product but it allows us to breathe.
The second stage, called the light-independent reaction, combines hydrogen from the water molecules with the carbon dioxide to make sugar which provides the energy and raw material for the plant.
The whole process of photosynthesis can be summed up in the equation:
| Light | ||||||
| 6CO2 | + | 6H20 | -------------> | C6H12O6 | + | 6O2 |
| Carbon Dioxide | Water | Chlorophyll | Glucose | Oxygen |
|---|
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