L20: PHOTOSYNTHESIS

1. OBJECTIVES

- Relate the light intensy with the photosynthesis process.
- Measure the rate of photosynthesis.
- Identify the products of the process and the variables that can affect it.

2. MATERIAL

- Algae (Elodea)
- 600 mL beaker
- Test tube
- Tap water
- Funnel
- Light souce
- Metric ruler

3. PROCEDUCE

1. First we assigned the different distances to do the experiment and compare the results to each group.
2. We took the 600 ml beaker and placed 7 g of an algae under a clear funnel inside the beaker. The funnel was raised off the bottom on pieces of blue-tack to allow unhampered diffusion of CO2 to Elodea. 
3. We didn't have sodium bicarbonate so we filled the beaker with tap water, the algae and the funnel should be completely under the water.
4. Then we filled a test tube with tap water and placed the thumb over the end of the test tube. We turned the test tube upside down taking care that no air enters and no water comes out and we put this test tube over the end of the funnel (the skinny part)
5. We marked the level of the water on the surface of the test tube with a marker pen.
6. Each group placed the preapartion close to a light source, each group placed the preparation in a different distance 5, 10, 20 and 25 cm, and one with no light source.
7. We also measured the temperature.
8. Finally we left this preparation for and hour and a half. After this time we measured the difference of gas accumulation on the top of the test tube. 

4. QUESTIONS 

1. Identify the dependent and independent variable of this experiment?

The dependent variable is the gas accumulation and the independent is the distance of the light.

2. Using the data from your results prepare a graph and describe what happened to amount of gas in the test tube.

 Andrea's blog.

3. How much gas produced in the test tube after 1 hour? And 1 hour and half?

4. Write the photosynthesis equation. Explain each part of equation. Which substances are produced by photosynthesis? Wich gas is produced that we need in order to live? 

6 CO2 + 6 H2O--------> C6H12O6+ 6 O2

O2------------>CO2