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Green plants make food through a process called photosynthesis, using the energy from the sun.

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PHOTOSYNTHESIS Green plants make food through a process called photosynthesis, using the energy from the sun. Cells from the leave turn simple materials into rich energy food. The key elements for photosynthesis are: > Carbon dioxide > Water > Light energy CARBON DIOXIDE + WATER + LIGHT ENERGY GLUCOSE + OXYGEN A plant must have all of these substances in order to produce its own food. During photosynthesis the plants produce glucose and release oxygen as a waste product. The upper epidermis is the skin. Beneath the upper epidermis lies the palisade cells which are the chief food produces. Spongy cells are partly surrounded with pockets of air which enable the cells to exchange gases with the atmosphere. The stomata are small openings in the lower epidermis under the leaf. Leaf veins carry water and nutrients from the roots. Carbon dioxide enters through the stomata. Chlorophyll contained in cells of the palisade cells and spongy layers help absorb the sunlight and transport light energy into chemical energy. Carbon dioxide combines with water and photosynthesised into oxygen and sugar. Oxygen escapes through the stomata. ...read more.


I use the same amount of water in the test tube and in the beaker. I will also use the same light source. SAFETY: There isn't much to be worried about in this experiment when it comes down to safety issues, but there are a few problems that could be dangerous that I tried to minimize, and that is: * To handle the light source very carefully * Not to touch the light source when its just been used because it'll be very hot * To switch the power supply off when moving the light source closer to the plant. * And to wash your hands after finished doing the experiment. METHOD: I'll fill the beaker with 20ml of water. Then put the pondweed into the test tube and place the tube into the beaker. I'll then connect the lamp up to the power source and measure 35cms difference from the beaker and the lamp. I'll then turn the lamp on, and leave it for 1 minute. After that period I'll count the number of bubbles on the pondweed and take the results down. ...read more.


I managed to make it a fair test by: using the same amount of water, using the same measuring cylinder, the same light source and the same pondweed. Examining my results I located a change in results. At 25cms the number of bubbles that were made had dropped dramatically, from 4 bubbles to zero. This could have been caused by various reasons. One of them could have been because I continued the experiment on the next day and that could have been the reason for the drop. To gain more accurate results I could have done the experiment on the same day, and scan the test tube more closely for more bubbles. To improve the experiment I could repeat the test a few more times to increase the accuracy of the results. I should have the experiment on the same day so I wouldn't get anomalous results. I could have prevented sunlight from getting into the room by covering the windows with blinds, and I could do the experiment on computer to get much more accurate results. Overall I think that the results didn't come out accurate, this is because of the fault in the results, and the reason for this is because I did the experiment on two days instead of one. ...read more.

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