Staying Up All Night ...

[j4y3m]

I'm gaurding the door.

[TRshady]

lol, ill simply walk out the front then.

3:30am! .... congrats mate ... we deserve a pat on the back ... cant reach ma own though, anyone wanna be the honor?

[j4y3m]

No thanks. I wish I has some coke.

[TRshady]

trust me mate,

the drugs dont work ... they just makes you worse, but I know I'll see your face again.

Well, not yours as in you ... but ummm ... (hey Ukman and Skweeky! )

[j4y3m]

Coke Cola.

[TRshady]

no, im TRshady .... bless.... your tired, (aint we all .. you and me that is).
Im surpised im still awake though, tis a record for me .. latest ive stayed up till now is 8pm ...so whoop de doo great, tis hard being so bloody good at everything.

[j4y3m]

i've stayed up all night plenty of times. Once I stayed up for 48 hours straight.

[TRshady]

wow?! ... really? ..... wait ... whats that? a flying pig?
Nah, I believe ya .... to a certain extent? ... (dont mean 4.8hours do you .. coz even I've managed that! , lol.

[j4y3m]

It was because I was travelling the counrty. I can't sleep while I move.

[TRshady]

but we all move in our sleep ... explain that one? , lol.

Heres what me dont for science this morning .. dont know what the hell im talking about though:

Science Coursework
The effect of light intensity on photosynthesis


Introduction

Photosynthesis is the term used to describe the process in which green plants (and few other organisms) make use of the energy from light to convert carbon and water to form the basic sugar – glucose. Photosynthesises able to take place in all green plants that have a sufficient amount of carbon dioxide, the lights, water and oxygen. This includes certain types of bacteria.

Due to photosynthesis being a major factor to how and if a plant survives, they are specially adapted in order to allow the process to work easier and more effectively. First off, and probably the most notable feature is the large broad leaves of a plant which give a larger surface area therefore making it more suitable for absorbing a substantial amount of sunlight. To allow diffusion to work better and allow the carbon dioxide to diffuse, the leaves are also relatively thin which in turn allows sunlight to pass through the leave easier.

The symbol equation for photosynthesis is:

6CO2 + 6H2O    C6H12O6 + 6O2
Carbon dioxide + Water  Glucose + Oxygen

Another way a plant is adapted for photosynthesis is by its roots, which are also adapted in a way to perform more efficiently. Plants roots have ‘Root hairs’ and this increases the plants surface area by a large amount which results in more water being absorbed easier which is a very important factor of photosynthesis.

The stem is also adapted and is long, strong which anchors the plant to prevent it being blowing away and also means the leaves are pushed closer to the sun. Another feature of the stem is that the stem is very thin; only one cell thick which means water absorption is even easier. Inside the stem are the Phloem and Xylem tubes which make the process of transporting water around the plant easier, mainly to the leave and taking glucose from the leaves and to a place in the plant where glucose is needed more. In some cases, the stem has features to help for defence such as spikes which cause damage and ward off certain threats.

There are factors that limit the rate of photosynthesis and the main being the concentration of carbon dioxide, which, being an important part for of the process, without enough will result in a very slow, if still possible reaction. The temperature of the plant also affects the rate of reaction because the hotter something is, the faster particles move which in turn gives a higher chance of collisions and cause reactions.

Light intensity also affects the rate of reaction, as when the intensity is increased, the rate of the photosynthesis is also increased for a short period but soon stops. With the addition of more carbon dioxide, the rate kicks up again so consequently prove that the rate of photosynthesis is affected not only by the amount of present carbon dioxide but also the intensity of the surrounding light.

Another factor to what determines the rate of photosynthesis this is by the following example. If the plants temperature was to be at a low state and was given an increase of light intensity and increase in rate would be notable but soon stop. Though on experimentation, giving the plant a higher temperature and then exposing it to the same intensity of light allowed the process to run a lot longer which proves that temperature affects the rate of photosynthesis.

Conclusion

The rate of photosynthesis was recorded by the number of oxygen bubbles which were produced in one minute. This was the result of an experiment which involved placing pondweed into a beaker of water with hydrogen carbonate (in order to maintain a good supply of carbon dioxide). Then placing a lamp close to the beaker which then caused bubbles to begin producing. Each minute the lamp was moved 10cms from the beaker till it ended up 100cm away and the experiment was complete.

The data collected shows this as its clear from the results that the number of oxygen bubbles which are produced, slow down as the lamp is placed at a greater distance from the pondweed. The averages calculated from all three of the experiments carried out show that a noticeable decrease of oxygen bubbles were produced with 143 bubble produced with the lamp was at a distance of 0cm, 40 bubbles produced with the when the lamp was positioned 50cem away, and finally, only 1 bubble was produced when lamp was at a distance of 100cm away.


Evaluation

The results obtained from the test show that the rate of photosynthesis is in fact effect or depends on the light intensity exposed to the plant, and therefore also mean that the experiment was carried out accurately.

There were no apparent errors when viewing the results, only slight differences which I believe are down to post calculations and recording which caused the graph to appear as a curve more then a straight line.

Error and Improvement

The results obtained from the experiment could have been a lot better as it was clear many factors to consider, or point to think about, one being how the oxygen was measured. Equipment and dedicated tools are used at most times to ensure accuracy, but in this case, all that was used was our eye which obviously cannot be trusted fully as there is only so much the naked eye can see.

This meant that there is little chance results gained from the experiment can be called accurate because first off, a lot of the air for example, is dissolved into the water and slowly rises to the air which would not have visible to the naked eye, let alone the bubbles which to small to see.

An alternative way of going about things would be to collect air rather then try counting it. With the use of pondweed, a paperclip, measuring beaker and measuring cylinder this could be done by using the paper clip to add weight and stop the pondweed floating in a measuring cylinder filled with water. Then covering the weed with a measuring beaker and allowing the photosynthesis process to take place means any oxygen produced would rise to the top of the beaker and after a minute, simply counting the amount of air collected would give us much better results. The air would be measured in cm3.

Another factor which could have lead to the experiment not being accurate is the pondweed itself. Apart from the place they were collected from, the pondweed collected from the experiment were randomly chosen which meant they were not the same weight, not from the same plant and not the same size, obviously making the test unfair to a certain extent.

Ways to improve on this factor would be to measure the pieces of pondweed before use and also that the pieces were from the same plant, which was not the case in our experiment. This must have made the experiment un-accurate along with the weight which was different for each meaning there was variation in the surface area so amount of oxygen produced couldn’t have been the same for each.

As heat effects a reaction, there are steps that can be taken in order to prevent the amount of heat transfer. Firstly is with the use of an energy saving bulb which in turn gives off a smaller amount of energy, therefore reducing the amount of heat transfer affecting the experiments results.

With light being a factor, a problem of this effecting our results was to simply do the experiment in a dark room and this way, light doesn’t effect our results and we can be assured our results are accurate as possible without this having a noticeable effect. Throughout the experiment, modifications had been made and alternative methods for the problems had also been conjured.