Science Exit Project

BY: Zarafshan AClass 851 2010-11

MS: Baez

The effects of light on plants

growth:

How does light affect plants

growth?

Research• Every living thing need nutrients, plants get energy

from sun to make their own food. They use the process of photosynthesis which is how they make glucose. The glucose is needed for the plants so they can survive and it is also needed to help the plants grow. Without the sun energy plants can’t live or grow.

Hypothesis

• I hypothesize that plants in full light will grow better and healthy compared to the plants in dark and partial light, because sunlight is necessary for plants to grow healthy.

Material • 27 sunflower seeds• Water • A bowl• 9 paper cups [ same size]• Potting soil • Scissors [ to make holes in cups]• Saucers [ or plastic lids for under the cups]• Sunlight• Marker • Ruler [cm]

Procedure1. Soak 27 sunflower seeds in water overnight to soften their seed coats. 2. Make three small holes in the bottom of 9 paper cups. 3. Label 3 cups with full light[ FL], 3 cups with dark[D] and 3 cups with partial light. 4. Fill each cup with potting soil and place them on saucers, plant 3 seeds in each

cup and water each cup. Keep all the cups in the same place until the seeds germinate.

5. Choose one seedling in each pot that has the strongest stem and the most leaves, remove the other seedlings.

6. Place 3 [FL] cups in a sunny window, 3[ D] plant in a dark closet, and place the 3 [PL] cups in sunny window for few hours and then the rest of the day with dark plants. Water each plant equally every day.

7. After two weeks measure the height of each plant and record the plant growth in all group.

8. Record the average plant height, average leaves and size of leaf. 9. Graph your result.

:Experiment:

Data Measurement of each Plants height after 2 weeks.

Plants in group

Heig

ht o

f pla

nts i

n CM

plant #1 plant#2 plant#30

2

4

6

8

10

12

14

16

18

20

Dark plantfull light plantspartial light plants

Average height of plants

0

2

4

6

8

10

12

14

16

DARK FULL LIGHT PARTIAL LIGHT

Heig

ht o

f pla

nts i

n CM

Average height of plants:

Average # of leaves

plants group0

1

2

3

4

5

6

DARKFULL LIGHTPARTIAL LIGHT

# of

leav

es

The average size of plants leaves

Series10

0.5

1

1.5

2

2.5

3

3.5

4

4.5

DarkFull lightpartial light

Plants groups

Size

of p

lant

s mea

sure

d in

Cm

Result• The bar graph shows the average height of plants of

each group. According to my data the average height of dark plants is 14.6 cm, full light plant is 9.3cm and partial light plant is 10.1cm.

• The third bar graph shows the average number of leaves in groups. It says that average leaves of dark plant is 2, full light plant is 5, and partial light plant is 4.

• The last graph shows the average size of leaves. The average size of dark plants leaves is 0.5 cm, full light plant is 4 cm, and partial light plant is 3.4 cm.

Conclusion:• In conclusion, I can say that the hypothesis

that I made in the beginning of my experiment is true because the plants in full light are grown better and they are healthy. Indeed the height of dark and partial light plants is greater than Full light plants but as you see the average number and size of leaves of Full light plants is grater than others that means these plants are healthy and better.

Source of errors:• For the source of errors I will say that 1. I should repeat my experiment again.2. I can try this experiment with different soil,

may be the result will be different.3. I can change the time for partial light in sun

and in dark.

Recommendation:• If I had chance to do this experiment again I

will try to collect more data about the plants and I will do more research.