1. Material
- Algae
- Beaker
- Test tube
- Funnel
- Sodium bicarbonate solution
- Light source
- Metric ruler
2. Objective
- Relate the light intensity with the photosynthesis process.
- Measure the rate of photosynthesis.
- Identify the products of the process and the variables that can affect it.
3. Procedure
First of all, take a big beaker and every group will place a sprig of algae under a clear funnel inside the beaker. Place the wide end of the funnel over the algae as the image you have below. The funnel is raised off the bottom on pieces of blue - tack to allow unhampered diffusion of CO2 to Elodea.
After, fill the beaker with the sodium bicarbonate solution and the algae and the funnel should be completely under the solution.
Fill a test tube with the solution. Place your thumb over the end of the test tube. Turn the test tube upside down, taking care that no air enters.
Mark the level of solution on the surface of the test tube. More late, place your preparation close to a light source and each group will place its preparation in a different distance from the light souce.
Our group use the 25 cm.
Measure the temperature and finally, leave the preparation 1 hour and a half and after this time measure the difference of gas accumulation on the top of the test tube.
4. Questions
1. Identify the dependent and idependent variable of this experiment.
The dependent variable is the gas accumulation and the independent is the distance of light.
2. Using the data from your results prepare a graph and describe what happened to the amount of gas in the test tube.
3. How much gas was produced in the test tube after 1 hour? And 1 hour and a half?
t0 = 10:11 The difference of water in test tube is 0,5 cm.
t0 = 22ºC
t15= 22ºC
t49= 23ºC
t99= 25ºC
4. Write the photosynthesis equation. Explain each part of the equation. Which substances are produced by photosynthesis? Which gas is produced that we need in order to live?
6 CO2 + 6 H2O ------------- C6H12O6 + 6 O2
O2 -------- CO2
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