Investigation Into the Colour of Light Needed to Start a Photosynthesis Reaction
Diagrams
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Method
The apparatus for this experiment will be setup as shown in the
diagram, for all the experiments the coloured filter will be 5cm away
from the white light bulb, which is a 60watt bulb, and the beaker will
be 20cm away from the edge of the coloured filter. Just before the
experiment takes place we will place the pond weed (which has been in
darkness for at least 24 hours to stop it any photosynthesis) into the
beaker. I will then place the funnel over the pond weed and place the
test-tube into the beaker (like the diagram above) I will then fill
the beaker up with cold tap water till it covers the bottom of the
test tube (450ml). This is so that we can easily count the oxygen
bubbles as they come off the pond weed. Now that the experiment is
ready to start, I will turn on the light for one minute, then after
the first minute I will count how many oxygen bubbles come from the
pond weed in the second minute. I will repeat this stage again once 10
minutes has passed. The preliminary experiment was done to check my
prediction of what I think will happen. For this I used red, green and
blue filters. The main experiment will be done with more colours if it
proves successful - I will repeat the experiment with more colours:
red, orange, green, blue and purple filters. I will take three
readings for the preliminary experiment and five for the main
experiment so that I can take an average for each colour.
Fair Test
* Pond weed is from the same pond.
* Pond weed kept in dark for 24+ hours.
* Pond weed stored in same conditions, darkness, temperature etc…
* Same sized pieces of pond weed (~5cm)
* Same temperatures (fridge, room and water)
* Same room and cold water from the same tap.
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.
In the second experiment with the green color, I can safely conclude that the color green in this case is very soluble and we would need longer filter paper, perhaps more time to safely separate the different colors that make up the color green.
at the small end of the axis to see a more reliable pattern. I could
As the light is increased so would the rate of photosynthesis. Apparatus: boiling tube, 250ml beaker, bench lamp, ruler, sodium
I added ½ tablespoon of baking soda to 4 cups of water. I added a small drop of liquid soap to the water and stirred to mix. I used the end of a straw and cut out 20 circles of spinach leaves. I pulled the plunger completely out of the syringe and put the leaf circles into the syringe. Next I pushed the plunger back in. I used the syringe to suck up the baking soda water until the syringe was about ¼ full of liquid. I placed my finger over the end of the syringe and pulled back on the plunger as far as I could without pulling the plunger out. I repeated this step three times. All the leaf circles sunk to the bottom of the liquid. I placed the spinach into a clear glass with about 2 inches of baking soda solution. I blocked out all light. I set the lamp with a compact florescent light bulb. I placed the glass in front of the lamp. I counted the number of circles that floated after each minute for 20 minutes (positive control). I created a negative control by not placing compact florescent light bulb and not placing the glass in front of the lamp. I counted the number of circles that are floating. I repeated the experiment with fresh circles and used regular water plus soap for all steps instead of baking soda and soa...
The Effect of Light Intensity on the Rate of Oxygen Production in a Plant While Photosynthesis is Taking Place
An Analysis and Evaluation of Data from Photosynthesis Experiments Graph analysis This is my analysis for the investigation in to the affect of light intensity on the rate of photosynthesis to the Canadian pondweed, elodea. In the results the pattern is that when the light intensity is higher the readings are generally higher. On the graph the less the light intensity the lower the gradient of the curve. the equation for the photosynthesis process is; CO2 + 2H2O + Light Energy = =
filters and count the number of oxygen bubbles given off using a pencil dot technique. Prediction I predict that with a blue filter the photosynthetic rate will be the as blue is a highly absorbent color it also has a short wavelength carries the most energy. The color to have the least photosynthetic rate will be green as it has quite a short wavelength so a lot of energy will be reflected by the plant and not absorbed in the sand. Yellow and orange will have average photosynthetic rates. although orange will be slightly more as it is more absorbent than yellow even low it has a longer wavelength and does not carry as much.
To make the test fair I will use the same amount of water and the leaf
Two electrical wires * Stopwatch * Thermometer Method I put a piece of Elodea Canadensis (pond weed) in a test tube and covered it with water. The test tube was then placed in a beaker with a thermometer so that the water stayed the same temperature, this was then placed in a cardboard box with a bulb attached to a voltmeter by the electrical wires so that I could concentrate how much light the plant got. I varied the voltage (intensity) of the bulb and counted how many bubbles of oxygen were created at each voltage in one minute. I tested each voltage three times for accuracy for a minute each time. Results Preliminary Experiment Amount of bubbles Light intensity (lux)
* Count the number of bubbles seen in 1 minute which is a way of
The second part of this lab deals with photosynthesis. This lab has several experiments. In the first experiment students will learn about the effects that different colored test tubes have on photosynthesis in elodea sprigs.
Investigating the Effect of Light Intensity on Photosynthesis in a Pondweed Aim: To investigate how the rate of photosynthesis changes at different light intensities, with a pondweed. Prediction: I predict that the oxygen bubbles will decrease when the lamp is further away from the measuring cylinder, because light intensity is a factor of photosynthesis. The plant may stop photosynthesising when the pondweed is at the furthest distance from the lamp (8cm). Without light, the plant will stop the photosynthesising process, because, light is a limited factor. However once a particular light intensity is reached the rate of photosynthesis stays constant, even if the light intensity is the greatest.
The Effect of Light Intensity on the Rate of Photosynthesis in an Aquatic Plant Introduction The input variable I will be investigating is light, as light is just one of the 4 factors required in the green-plant process of photosynthesis. Photosynthesis is the process by which green-plants use sunlight, carbon dioxide, water & chlorophyll to produce their own food source. This process is also affected by the temperature surrounding the plant (the species of plant we experimented with, pond weed, photosynthesised best at around 20 degrees centigrade.) Light, temperature & CO2 are known as limiting factors, and each is as important as the next in photosynthesis. Light is the factor that is linked with chlorophyll, a green pigment stored in chloroplasts found in the palisade cells, in the upper layer of leaves.
the distance from the light source to the plant. Output - The rate of photosynthesis is to be measured by counting the bubbles of oxygen produced by the plant every two minutes, and therefore finding the rate of photosynthesis. Control - The amount of water available to the Elodea will stay the same. same level as the 400 cm3 beaker. The colour of the lamp will stay the same (yellow) as to plants Chlorophyll easily absorbs blue light.