Materials
3 bean seedlings of equal size
3 desk lamps with colored bulbs (red, blue, white)
Ruler
Watering can
3 identical pots with potting soil
Procedure
1. Plant one bean seedling in each pot with identical soil.
2. Place each pot under a different colored light (red, blue, white control).
3. Water each plant with 50ml of water every 2 days.
4. Measure plant height daily for 14 days.
5. Record leaf count and overall appearance at day 7 and day 14.
Observations
Blue light plant grew tallest at 18cm by day 14. Red light plant was shortest at 11cm but had the thickest stem. White light plant was 15cm with the most leaves (8 vs 6 for blue, 5 for red). Blue light plant showed slight lean toward the light source. Red light plant leaves were darker green.
Notes
Expected blue light to promote the most growth based on chlorophyll absorption spectrum. The height result matched, but the red light plant's stem thickness was unexpected. Room temperature was maintained at 22°C throughout.