To Learn: Plants

List of things that should take priority in revision:

• Transpiration is important to plants because it allows a steady stream of water to happen - when water moves out through transpiration, more water can be pulled in through the roots. This is possible because water is cohesive (molecules of water are attracted to each other). If you put little blobs of water on a desk that is slippery enough and they are close, the two little blobs will form one bigger blob.
• In intense light, guard cells become turgid, which causes the stomata to open, so rate of transpiration increases
• When the stomata is open, carbon dioxide, oxygen and water vapour can diffuse in (so photosynthesis can occur) and excess water vapour can diffuse out
• Using this apparatus, rate of water loss can be measured, because the bubble moves up with the intake of water. The faster the intake, the faster the rate of transpiration.
• To investigate the effect of wind speed, temp, etc. on the experiment above, just modify the environment; i.e. for wind, add a hairdryer, etc.