EXPERIMENT: PHOTOSYNTHESIS REACTIONS
There are two life sustaining reactions photosynthesis which converts energy from the sun into a usable form of energy for living things and cellular respiration which converts the energy that is stored in the product of photosynthesis into a usable form of energy for the cell. The equation for photosynthesis is 6H2O + 6CO2 -➔ C6H12O6 + 6O2. Oxygen gas is a waste product for the plant and is released into the atmosphere. In this lab you will look at several things that can affect the rate of the reaction by looking at the amount of oxygen gas produced.
OBJECTIVES
Determine factors that affect the rate of the photosynthesis reaction.
Online lab
This animation will demonstrate one factor that affects the rate of the photosynthesis reaction. You will be observing a water plant, elodea undergo photosynthesis. The solution that the elodea is in is a solution of sodium bicarbonate (baking soda) and water. The sodium bicarbonate provides the carbon dioxide needed for the photosynthesis reaction, this factor will remain constant in this animation. The factor that will be tested is the light intensity. The light intensity will be varied by changing the wattage of the light bulbs. For each trial, you will count the bubbles released by the elodea undergoing photosynthesis. Be sure to record your observations and data to use to complete the assignment.

This experiment will show the effect of light intensity on the rate of photosynthesis.
For each trial, you will be counting the number of bubbles the elodea plant releases.
Remember to record you data and any observations on your data sheet.
In trial one, the light is from a sixty watt bulb and is 20 cm from the beaker containing the elodea set up.
Once the time starts, count the number of bubbles the elodea releases for 3 minutes.
Start the timer and count the number of bubbles released in 3 minutes. Record your data at the end of the trial.
For trial 2, the light will still be twenty centimeters from the beaker, but the bulb has been replaced with a one hundred watt bulb.
Start the timer and count the number of bubbles released for 3 minutes. Remember to record your data at the end of the trial.
Again, for trial three, the light will be twenty centimeters from the beaker. This time the light bulb is a one hundred fifty watt bulb.
Start the timer one more time and count the bubbles for 3 minutes. Record your data.
Now use the data you collected to complete the assignment.

In complete sentences, answer these questions in the essay box below. Be sure to use the data and observations you collected if needed.
1) What are the bubbles that the elodea released made of?
2) What conclusions can you draw about the relationship between light intensity and the rate of photosynthesis? Be sure to refer to your data and justify your response.
3) What is another way that the intensity of the light could be tested? Describe your procedure.
4) Look at the photosynthesis reaction 6H2O + 6CO2 -➔ C6H12O6 + 6O2. What do you think might be other factors that can affect the rate of this reaction?
5) Make a hypothesis about your answer to question 4.
6) Design an experiment to test your hypothesis in question 5.