PLANTS AND SUNLIGHT
Biological Science – Plant Needs – Sunlight
The Student will be able to prove that a plant needs light in order for
it to develop correctly.
seeds (any alternative seed will do), potting soil, flower pots of plastic
containers, box, aluminum foil, houseplant, two plants the same size
BACKGROUND INFORMATION: Plants need food and can make their own food. But they need things from which to make
their food. Green plants need carbon dioxide from the air, water, and minerals
from the soil, and energy from the sun.
Only in light can a green plant make food. The process of food making is called
photosynthesis. In photosynthesis, the
carbon dioxide and water are changed to carbohydrates and oxygen. Food can only be made in the presence of
chlorophyll. Chlorophyll is the
substance responsible for a plant’s green color.
When a green plant is deprived of sunlight, it soon loses
its chlorophyll. It cannot make food,
so it dies.
the sunflower seeds overnight.
Then plant three sunflower seeds in each pot and put them near the
window. Water the pots well. Now cover one pot with the cardboard
the first true leaves appear on the plants that are uncovered, remove the
box from the other pot.
with the students what happened to the plants. Why did the sunflower seed under the box not grow? Do plants need light to grow? Do they need light to remain healthy?
- When a
plant gets no sunlight, it cannot make food. Without food the plant will
die. Use two plants of the same
size. Cover one with a box or place it in a closet to block the sunlight. The plant that did not receive
sunlight will lose some of is green color. It will not look as healthy as the other plant. Make sure it now receives sun and watch
for it to return to health.
- Put a
potato in a dark, warm spot for several weeks. What happens to the potato?
If left in the dark for several months, will the potato die? Try it.
three of four seeds in the bottom of a shallow bowl and place a wet sponge
over them, Keep them damp. When
the seeds sprout, watch to see what happens to them. Turn the dish. Do the seedlings turn toward the light?
- Put a
rock or a board on a patch of grass, leave it for two weeks. Take the rock off and observe. What has happened to the grass? Is it a different color from the
surrounding grass? Has the grass
died? Now leave he rock or board
off the grass. Does the green
color return to the grass?
a plant log about one of the experiments.
the students make up an activity of their own with plants and sunshine.
Have the students keep their plant long using a word processing sheet or
have them create a chart in excel to fill in daily.
Adapted from 1990 Aims