Photosynthesis Virtual Labs

Photosynthesis Virtual Labs.

Lab 1: Glencoe Photosynthesis Lab

Analysis Questions

1. Make a hypothesis about which color in the visible spectrum causes the most plant growth and which color in the visible spectrum causes the least plant growth?

If the pigment chlorophyll reflects green light and absorbs red light, then green light will cause the least plant growth and red light will cause the most plant growth.

2. How did you test your hypothesis? Which variables did you control in your experiment and which variable did you change in order to compare your growth results?

I tested my hypothesis by growing spinach, lettuce, and radish plants under various colors of light. I controlled which seeds I grew, how many lights the plants were under, for how many days they were grown for, the type of soil, and so on. I changed the color of light the plants grew under to see if my hypothesis was correct.

Results:

Filter Color	Spinach Avg. Height (cm)	Radish Avg. Height (cm)	Lettuce Avg. Height (cm)
Red	18.33	12.83	11.83
Orange	14.67	8.5	6.5
Green	2	1.5	3.17
Blue	19.5	14	12.33
Violet	16.17	10.33	8.33

3. Analyze the results of your experiment. Did your data support your hypothesis? Explain. If you conducted tests with more than one type of seed, explain any differences or similarities you found among types of seeds.

The data supported half of my hypothesis; green light had on average the lowest amount of plant growth. However, red was in second place for most plant growth. Blue light caused the most plant growth instead of red light. I found that the different types of seeds generally gave me the same results regarding which light caused the most plant growth.

4. What conclusions can you draw about which color in the visible spectrum causes the most plant growth?

I can conclude that blue light ultimately causes then most plant growth, but red light also causes a lot of plant growth; slightly less than blue however.

5. Given that white light contains all colors of the spectrum, what growth results would you expect under white light?

I would expect average plant growth under white light; more than green light but less than blue light. Because white light has green light in it, that would be reflected and not help the plant grow at all. But blue and red light would also be in white light, causing the plant to grow more, not as much as if it were all blue or red light though.

Lab 2: Photolab Experiment

Question:

Does light intensity affect the rate of photosynthesis in a plant?

Hypothesis:

If plants need light in order to perform photosynthesis, then the more light intensity there is, the quicker the rate of photosynthesis will be.

Experimental Parameters:

Dependent variable- rate of photosynthesis

Independent variable- light intensity

Constants- type of plant, light bulb, amount of time under light, same environment

Control- white light, zero light intensity

Data Table:

Number of Bubbles Produced (Rate of Photosynthesis) from Various Light Intensities

Light intensity	0	10	20	30	40	50
Number of bubbles from plant stem in one minute	0	7	11	12	11	12

Conclusion:

In this lab I asked the question ‘Does light intensity affect the rate of photosynthesis in a plant?’. I found that light intensity only affects rate of photosynthesis if there is a large lack of light. 0 light intensity caused no bubbles (hence no photosynthesis) and 10 light intensity only caused 7 bubbles to appear; not as much photosynthesis as the other light intensities, but only shy a few bubbles. 20, 30, 40, and 50 light intensities all had either 11 or 12 bubbles come from the plant stem. This shows that plants only need a little light to photosynthesize. I can relate these findings to the photosynthesis equation, carbon dioxide and water, with sunlight, produce glucose and oxygen. This supports our claim and data because as long as the plant had some light, even very little, it was still able to photosynthesize because of the sunlight presence.

This lab was done to understand how light intensity affects the rate of photosynthesis in plants. From this lab I learned that as long as light is present to a plant, it will be able to photosynthesize. This helps me understand the whole concept of the process of photosynthesis, something I have been studying in Biology class. I now see how important light is in the equation of photosynthesis and with no light, there will be no photosynthesis. Based on my experience from this lab, I could apply this when I grow plants in my garden. I will place them strategically so that they get the most sunlight they can so they are able to photosynthesize effectively. Even if they are in partial shade sometimes, it will not be a huge problem because plants only need a little light to be able to photosynthesize.