1. Experiment: Phototropism (growth in the
direction of light)
Objectives:
Investigate the effect of light on root and stem growth
Materials:
Petri dish
Aluminium foil
Filter paper
Lentils
Procedure:
1. Place two circles of filter paper inside the Petri dish, taking care to ensure
that the paper is touching the edges
2. Moisten the paper with a small amount of water and place the lentils as
indicated.
3. Moisten two pieces of filter paper and then cover the lentils with them. Cut a
circular piece of aluminium and place it on top of the filter paper. Put the top
on the Petri dish.
4. Put the Petri dish in a light place, however, the area shouldn´t receive direct
sunlight. Leave it in the same place for three or four days.
Results:
1. After three or four days, remove the
Petri dish´s cover, taking care not to alter
the position of the seeds. Observe the
development of the roots and stems.
2. Make a drawing of what you have found
in the Petri dish.
Questions
1. Why did you moisten the filter paper?
2. Why did you cover the seeds with the
paper?
3. Do the seeds receive light?
4. Did you observe any relation between
the light and the development of the
roots and stems? Explain this.