Two experiments were performed to demonstrate the effect of ultraviolet
radiation on plants and bacteria. Another experiment was performed to
further demonstrate how glass filters ultraviolet radiation. The glass
was used to mimic the effects of ozone on ultraviolet radiation.
Experiment 1:
1. String bean and mustard green seeds were germinated on cotton in
petri dishes for 3 days. During that time, the seeds were given a
few drops of water daily.
2. On day 4, the germinated seedlings were transferred to the pots
containing potting soil. Each seed type had two test groups and
one control group. Eight plants were used in each group.The two
test groups differed in that one was shielded by glass when
exposed to ultraviolet radiation (u.v.r.) -labeled (SE)- but the other
was not shielded when exposed to u.v.r. and it was labeled
(U.S.E.).
3. From day 5 to day 10 the test groups were exposed to (u.v.r) for 2
hours daily.
Experiment 2:
1. Expose a fluorescent surface to u.v.r.in a dark room.
2. Expose the fluorescent surface to u.v.r. but this time place a
glass plate in front of the u.v.r. lamp.
Experiment 3:
1. Grow E.Coli cells in nutrient media for 24 hours.
2. Take out 1 mL of the E.Coli cells to use as the control group. Do
not expose this group to u.v.r..
3. Expose the remainder of the cells to ultraviolet light.
4. At 5, 20, and 60 seconds take out .1 mL of E.Coli cells
Place each group of cells in separate test tubes and label each one.
5. Dilute each group of cells to 10-6 concentration and plate out
.1 mL of cells on nutrient agar then incubate for 24 hrs.