Rate Of Photosynthesis Essay, Research Paper

An Investigation to See

if Light Intensity Effects the

Rate of Photosynthisis.

I’m going to investigate the amount of light used in photosynthisis to see if it

has a noticable effect when you increase or decrease the light intensity.

Photosynthisis is the way in which light and carbon-dioxide is used by a plant to

produce energy in the form of starch.

6CO + 6H O = C H O + 6O

The factors that effect the rate of photosynthisis are the amount of light, the

amount of carbon-dioxide (CO ) and the temperature that can be used by the plant. I

have already carried out the experiment to see the effects on a plant when you

change the amount of carbon-dioxide. I found that the more carbon-dioxide used the

faster the plant photosynthisied. To see if this rule (More of a limiting factor = The

quiker the rate of photosynthisis) works, I will plan a experiment . My experiment

will be to see if the light intensity follows this rule. I will use a aquatic plant as they

can be used to see the effects under water.These plants still cotain chlorophyll (a

light absorbing die thats converts light energy intochemical energy).

Aim

To see if the amount of light intensity will effect the rate of photosynsis.

Prediction

I predict that the more amount of light you allow the chlorophyll to absorb the

quicker the rate of photosynthisis will be. I think this because the amount of light is

a limiting factor in the reaction of photosynthisis. So if you alow more of a limiting

factor to be present in the chemical reaction it will all most certainly speed up the

rate of that reaction. If a plant had the right amount of carbon-dioxide and the right

temperature but the wrong amount of light the reaction of photosynthisis will be

slow. This is because the reaction needs the light to let the plant turn the light

energy to a chemical energy.

Method

Equipment

Fresh pond weed

250ml Beaker

Funnel

Test Tube

Power Pack

Lamp

200ml of Tap Water

1 Spactular of Sodium Bicarbonate

Stop Clock

Method

Set up the Equipment

Add 200ml of Tap Water

Place the pond weed Inside the upside down Funnel

Add 1 Spactular of Sodium Bicarbonate Inside the Upside Down Funnel

Set the Lamp (thats connected to the power pack) to the Chosen distance Ethier

10,20,30,40,50cm away from the beaker

Start the Stop Clock and time for three Minutes

Count the Number Of Bubbles that the Pond Weed Gives off.

Remember Repeat This Experiment 6 Times Using a Different distance Each

Time.

Fair Test Points

Set the lamp to the same voltage

Take results for the same amount of time

Use the same amount of sodium bicarbonate

Results

Distance of lamp Bubbles realised Average

from the plant in 3 minutes

10

20

30

40

50

A graph to show the effects of light to the rate of photosynthisis