Photosynthesis Virtual Lab

BACKGROUND INFORMATION
Photosynthesis is the process in which plants use light energy, water, and carbon dioxide to produce food. Plants use the food they make for growth and carrying out other life processes. Sunlight is the natural energy source for photosynthesis. White light from the sin is a mixture of all colors of the light spectrum: red, orange, yellow, green, blue and violet. Light can either be absorbed or reflected by substances called pigments. Most plants are green because the pigment chlorophyll reflects green and yellow light and absorbs the other colors of the spectrum.

PROBLEM

Which colors of the light spectrum are the most important for plant growth?

HYPOTHESIS

If each plant were to grow under a blue light source, then the height of the plants will be taller in comparison to other light colors.

If each plant were to grow under a green light source, then the height of the plants will be shorter in comparison to other light colors.

INDEPENDENT: color of light

DEPENDENT: height of each plant

CONTROL: soil, moisture, water, temperature

PROCEDURE

1. Click the “Video” button. Watch the animation to learn about how light affects photosynthesis.
2. Make a hypothesis about which part of the light spectrum causes the most plant growth and which part of the light spectrum causes the least plant growth. Assume that all conditions except the color of the light are the same for the seed as it grows.
3. Test your hypothesis by choosing different plant seeds and observing how the plants grow under different colors of light.
4. Choose the type of seed that you want to test and click its seed packet.
5. Click the arrow on the color display to select a color light filter for each set of three plants.
6. Start the experiment by clicking the light switch to the “ON” position.
7. Observe the plant growth.
8. Click the ruler and drag it to each plant to measure the height. Use the calculator to average the heights of the three plants under each color light filter. Record your calculation in the Table.
9. Click the “Reset” button. Repeat the experiment using a different color light filter and same type of seed.
10. After all the color filter have been tested on one seed, conduct the experiment again with another type of seed to verify your conclusions.

DATA/GRAPH

Filter Color	Spinach Avg. Height (cm)	Radish Avg. Height (cm)	Lettuce Avg. Height (cm)
Red	18	12.6	11
Orange	14	8	6
Green	3	1	3
Blue	19	14	12
Violet	16.3	10	8.3

RESULTS/CONCLUSION

In conclusion, my first hypothesis was proven incorrect whereas my second hypothesis was supported. In fact, my results showed that the color blue rather than the color violet would be more efficient towards faster plant growth in terms of photosynthesis. On the other hand, my results also showed that the color green has the least effective plant growth in comparison to the other colors of light. Thus, we can conclude that the color blue from the light spectrum is the most significant for plant growth.

JOURNAL QUESTIONS