Light Intensity The Rate Of Photosynthesis example essay topic

Biology Coursework! V Does The Light Intensity Affect the Rate of Photosynthesis The Investigation In this experiment I will investigate the affect in which the light intensity will have on a plants photosynthesis process. This will be done by measuring the bubbles of oxygen and having a bulb for the light intensity variable. Variables The input variable which will be used in this investigation will be the light intensity (this will be a 100 Watt bulb being moved closer and further away from the plant). The outcome variable which will change as a result of this experiment will be the amount of oxygen made in the experiment due to the amount of light intensity increases (causing the plant to photosynthesis e more). Prediction predict that as the input variable, the light intensity increases (the light moved towards the plant) the outcome variable, the amount of oxygen, produced from photosynthesis will be larger.

Plants can absorb and use light energy because they have a green pigment, chlorophyll, contained in the chloroplasts in some of their cells. Chlorophyll allows the energy in sunlight to drive chemical reactions. Chloroplasts act as a energy transducers, converting light energy into chemical energy. So as the plant has more light the chlorophyll inside the chloroplasts can react faster absorbing in more light for food and energy. The equation for photosynthesis can help to predict the outcome of the investigation.

Light Energy Carbon Dioxide + Water 3 Glucose + OxygenChlorophyllThis shows that there could be three variables in this experiment, carbon dioxide, water and light energy. So in our case the variable light energy (light intensity) will be used. The equation also shows that if there is more light energy then more glucose and oxygen will be produced. I also predict that as the light is moved closer to the plant there will be more bubbles (oxygen) produced due to the increase of photosynthesis speed explained above.

So in conclusion I predict that the more light intensity there is on the plant the faster the rate of photosynthesis there will be. Fair Testing The fair testing will be carefully checked so the results do not come out to be void. The light intensity will be changed for it is the only variable used in the experiment. Though the temperature, watt of the bulb, amount of water, size of the plant and position of the clamp and stand.

The preliminary experiment I did has helped me to decide in which conditions / measurement I will use. The reason in which I will keep the other variables the same is because if increased they would increase the rate of photosynthesis making the experiment pointless and a waste of time. Also if they decrease then it will be likely that the rate of photosynthesis will decrease as well. Me and my partner in this experiment decided that we will set the timer to start after sixty seconds in which the light has been turned on, we chose this because the photosynthesis rate will have been rising and be at a steady rate to take the amount of bubble recording after one minute. We will be doing each light intensity test three times to get an average (for our graphs).

Apparatus The apparatus I will be using are: Clamp Stands Test Tube 100 Watt Bulb and Light Plastic ScreenStopwatchAutomatic Counter Water 1 Metre Ruler Light Meter Preliminary experiment The preliminary experiment was done to find out what range of values I will use and details of the measuring instruments. I decided that the amount of water will fill the test tube, the light intensity readings will be at 100 cm, 75 cm, 50 cm and 25 cm on the metre ruler, the stop watch will be turned on after 60 seconds of the light been on and the results will be taken three times and put into a results table. The results my partner and I ended up with where: 100 Cm between light and plant = 6 bubbles 25 Cm between light and plant = 12 bubbles will be measuring the light intensity with a light meter at each of the distances. When I do this, I will then find the light intensity by dividing the number which came up on the light meter into 1; this will be the light intensity. During the preliminary experiment I did not come up against any noticeable problems so no solutions where needed. Plan The plan or method I will be using will start of by placing a plant in a test tube filled with water.

This test tube will then be held by a clamp stand and around 100 cm's across from the clamp stand there will be a lamp with a 100 watt bulb in it. The 100 cm ruler will be placed between the clamp stand and lamp so you know how far to move the lamp after you record the bubbles for each light intensity. The light intensity will by using the light meter to record the readings at 100 cm 75 cm, 50 cm and 25 cms, then dividing the number which comes up on the light meter into one and the way they will be recorded are as follows: 1) Turn on lamp for 1 min 2) Start stop watch after 1 min of the light being on 3) For 1 min record the bubbles starting at the same time as the stopwatch 4) Write down results, then leave lamp off for 1 min then repeat the process for each measurement 3 times. I will intend to plot a graph.

Going up on the graph shall be the amount of bubbles and going across on the X axis will be the measurement. The amount of bubbles recorded on the graph will be the averages for each measurement (the reason for doing three results). The graph title will be! SS Graph to Show Bubble Amounts of Light Intensity! V Photosynthesis Investigation!" . During the investigation we were warned about what not to do.

We were warned not to stare into the light for it may severely damage our eye site, do not play with the scalpels for they are very sharp, do not touch the bulb so u don! |t burn your hand and leave the water alone (hence don! |t play with it, drink it) for it may cause illness. By Johnny W Biology Coursework! V Experiment to see if Light Intensity Affects the Rate of PhotosynthesisMethodThe method I used in this experiment started of by getting my apparatus consisting of 3 clamp stands, test tube, stem of plant, water with some carbonated water, heat proof screen, thermometer, scalpel, lamp, light meter, meter ruler, stopwatch and a counter. When my apparatus was set up I measured used the light meter to find out what the light intensity at each of my measurements. (20 cm, 40 cm, 60 cm, 80 cm 100 cm) I did this by using the reading I got for each of the measurements, you then divide 1 by that number to get the light intensity for that reading.

When I had those readings I put them into my results table along with my measurements, amount of bubbles and the distances. I measure the amount of bubbles per minute three times to make sure the readings are similar (not void), and also to get an average of bubbles per minute to plot on my graph. I measure the amount of bubbles every minute using a stop watch to keep record of the time and a counter to keep track of how many bubbles of oxygen have come to the surface. I did this process three times for all my distances. Results Distance (cm) Light Intensity (Arb Units) Amount Of Bubbles (Per min) Average 20 4.5 41 44 39 4140 3.0 23 23 21 2260 1.8 22 15 17 1880 1.0 14 13 15 14100 0.8 10 13 9 11 My results clearly show that the closer the lamp was to the plant the quicker the rate of photosynthesis is.

This is not surprising because the chlorophyll in the chloroplast can react / work faster when there is more light to take in for energy, then oxygen (bubbles) are given off more frequently by the plant. The trend on the graph is a great way of seeing how much my prediction was correct and it reflects both how well the experiment was done and to give a good, well backed up conclusion for the investigation. The trend shows the experiment was done at a satisfactory standard due to all the points going up in a good positive correlation with one anomaly. The anomaly is an anomaly because at five arbitrary units the bubbles per minute was a lot higher than the other light intensity points, though it goes with the trend of the points in which the points all increase in bubbles per minute as the light intensity increases. The rate of photosynthesis increases because plants can absorb and use light energy for they have a green pigment, chlorophyll, contained in the chloroplasts in some of their cells. Chloroplasts act as energy transducers, converting light energy into chemical energy.

The prediction I made was very well stated due to the fact that the things I predicted did happen. Such as when I stated, ! SSI predict that as the input variable, the light intensity increases (the light moved towards the plant) the outcome variable, the amount of oxygen, produced from photosynthesis will be larger!" . This shows that I had understanding of what was to come out of the experiment and that the experiment was done well enough to show that my prediction was correct. Overall my prediction was very accurate and the way the oxygen produced by the plant as the light intensity increased was very close to what my prediction stated. Conclusion In conclusion I have found from my experiment that my prediction was correct in saying that the higher the light intensity, the greater the rate of photosynthesis is.

The results and my graph show me that a plant releases more oxygen when there is greater light intensity. Such as in the equation for photosynthesis: Light Energy Carbon Dioxide + Water 3 Glucose + OxygenChlorophyllThis shows that light energy is one of the key components in making the outcome of glucose and oxygen, so with more light energy it is proved there is a larger outcome. I managed to assemble this conclusion from the results gathered because my results where very clear and my graph was extremely helpful. My results and my graph both show that as there was more and more light intensity the rate of photosynthesis continued to increase, my result table shows this by the numbers increasing, and my graph shows me by the trend line which is of positive correlation showing that the higher the light intensity, the higher the rate of photosynthesis.

My graph in a less accurate form would look like this: The trend line on the graph really helps to show that in conclusion in which as the light intensity is increased, the bubbles per minute also increases. The graph shows my experiment was done well leading to well taken results. The scientific reason for my conclusion is based up upon what I stated in my prediction and to explain my results, ! SS plants can absorb and use light energy because they have a green pigment, chlorophyll, contained in the chloroplasts in some of their cells. !" So this shows my prediction was correct for in my experiment and shown in my result table and graph the more light intensity there is on a plant the higher the rate of my photosynthesis will be. My prediction is very close to what I said the results will be so my prediction was correct and has been proven to be correct in my result table, graph and now explained again in my conclusion.

In conclusion the experiment was carried out and had great success proving my prediction to be correct and enabling solid and valid results which were able to be put in a graph. I believe my prediction could have been more accurate or more backed up if I had made a quantitative prediction. Though what I believed would happen did happen during the experiment which helped to understand the graph and the results which led me to be able to write a thorough report on them..