Biology Controlled Assessment Photosynthesis Year 9 Final Essay

Submitted By MirrorMirror_
Words: 2940
Pages: 12

Biology Controlled
Assessment Photosynthesis
Year 9
By Amira Wadar

1

Contents page
Ώ
Ώ
Ώ
Ώ
Ώ
Ώ
Ώ

Introduction
Equipment list
Method
Preliminary
Risk Assessment
Results
Evaluation
Ώ
Ώ
Ώ
Ώ

Method
Results
Secondary data
Hypothesis

Ώ Conclusion
Ώ Bibliography

2

Intro
In this experiment we are going to be focusing on photosynthesis and the amount of oxygen bubbles produced as the amount of light intensity increases.
What is photosynthesis and its importance?
Photosynthesis is the process in which an organism uses sunlight to absorb the nutrients such as carbon dioxide and water. Generally the organism creates a by-product, oxygen. The importance of photosynthesis is that without it, living organisms such as green plants wouldn’t have any energy as that is the main supplier.
Variables that affect the rate of photosynthesis.
There are 3 variables that affect the rate of photosynthesis, they are light intensity, carbon dioxide concentration and temperature. We could have used any of them however the easiest one to control is light intensity.
3

Intro
Variables that affect the rate of photosynthesis.
The reason why we didn’t chose the other variables to test is because that light intensity is the easiest to record. If we chose to do the temperature experiment, it would be a lot harder because temperature is hard to control and keep at a constant level.
During this piece of coursework I am going to be investigating the rate of photosynthesis when it is affected by the amount of light intensity that it is receiving. Equation for photosynthesis
Light energy is not in the equation rather it is on top of the arrow, because light energy is not a substance. 4

Intro
• The variable that I am going to investigate is light intensity. To achieve this, I am going to have a piece of elodea and from certain lengths, count the amount of oxygen bubbles that the it produces. Also throughout my experiment I am going to make sure that the only light that my elodea is receiving is directly from my lamp and not from others around me. In addition I am going to make sure that my results are as accurate as they could be by ensuring that my elodea is placed at the specific length from the lamp, to ensure that my results aren’t false.

5

Intro
From this experiment I hypothesise that the closer the elodea is to the lamp, the more oxygen bubbles are produced reason being, is that there has been an increase in a factor that can be limiting if the light from the lamp was not reaching the elodea
The independent variable in this experiment is light intensity. We chose light intensity because it is easiest to control, compared to temperature because it is extremely hard to control.
The controlled variable in this experiment are the following:






Elodea
Light intensity from the light
Solution
Temperature
Concentration (of the solution)

6

Intro
• I predict that the light intensity can affect the elodea and the amount of oxygen that the elodea produces because the rate of photosynthesis increases and decreases due to 3 factors light, temperature and carbon dioxide. If any of these elements are of a low supply then the rate will decrease because it cannot work efficiently, for example when a battery is running out in a remote control car the car starts to slow down. slowly but surely the rate of oxygen produced will reach a point in which the amount of oxygen produced will stay at a constant level.

7

Equipment


Boiling tube:




Lamp:




The boiling tube is used because that is where the elodea is placed along side the water. In addition we used the boiling tube because it is clear which helps to have a fair test because we are able to clearly see how many oxygen bubbles are being produced. Furthermore we used the boiling tube because it doesn’t allow the elodea to move around.
The light intensity must stay consistent to ensure that our results are as accurate as they can be. Also the lamp provides us with the variable that we can…