The Effects of Sea Water on Bamboo

Complexity level:	4
Project cost ($):	90
Time required:	1 day to prepare, 5 days for observation
Material availability:	Easily found
Safety concerns:	NA

Hypothesis

Watering bamboo plants with sea water will cause their growth to be stunted or will cause the plants to wilt and die.

Overview

Bambusa vulgaris (common bamboo)

The bamboo plant is known to be very fast growing, as quickly as several inches a day. This plant can achieve its full height in 4 months. This characteristic of the bamboo plant makes bamboo suitable for this experiment. It helps enable us to measure the effect of salt water on ithe growth of bamboo over a short period of time.

Osmosis

Osmosis is the movement/diffusion of water through a partially-permeable membrane from a solution of low concentration to a solution of higher concentration. In this experiment, the"membrane" is in fact the outer layer of the roots of the bamboo plants, as the sea water is absorbed through the roots via the process of osmosis. The high solution concentration consists of sea water and the liquid inside the roots is of lower concentration.

Scientific Terms

Osmosis, partially-permeable membrane, Bamboo, Bambuseae

Materials

The materials required for this experiment:

15 bamboo plants of equal height
15 pots
Soil required for the 15 pots
Sea water (enough to water 5 plants twice a day)
Tap water
Ruler (1 meter long)

Procedure

For this experiment, the independent variable the type of water used to water the bamboo plant specimens. The dependent variable is the rate of growth of the bamboo plants. This is determined by measuring the average height of the 5 bamboo plants in each group. The constants (control variables) are the number of times the plants are watered, the amount of water used and the type of plant and soil used.
The bamboo plants are divided into 3 groups with 5 plants in each group. They are labeled as group A, group B and group C.
Group A plants are watered with tap water twice a day.
Group B plants are watered with sea water only once on the 1st day. Subsequently the plants are watered with tap water twice a day.
Group C plants are watered with sea water twice a day.
The bamboo plants are watered as mentioned above and observed for 5 days. Their height is measured everyday and recorded in the table below.

Results

You should observe that the plants in group A will demonstrate fast growth. The plants in group B will show inhibited growth. Finally the group C plants will wilt and die.

Use this table below to help record the bamboo plants daily height (in mm).

Group	Plant	Day 1	Day 2	Day 3	Day 4	Day 5
A Water twice daily in tap water	Plant 1	300mm	455mm	606mm	750mm	903mm
Plant 2	300mm	450mm	599mm	743mm	895mm
Plant 3	300mm	451mm	594mm	745mm	894mm
Plant 4	300mm	445mm	595mm	757mm	905mm
Plant 5	300mm	449mm	606mm	755mm	906mm
Average	300mm	450mm	600mm	751mm	902mm
B Water once only in sea water on 1^st day. After that water twice daily in tap water	Plant 6	300mm	305mm	327mm	357mm	397mm
Plant 7	300mm	317mm	330mm	360mm	402mm
Plant 8	300mm	3045mm	336mm	366mm	405mm
Plant 9	300mm	311mm	332mm	362mm	405mm
Plant 10	300mm	308mm	331mm	365mm	401mm
Average	300mm	314mm	332mm	364mm	389mm
C Water twice daily in sea water	Plant 11	300mm	304mm	304mm	304mm	304mm
Plant 12	300mm	307mm	307mm	307mm	307mm
Plant 13	300mm	302mm	302mm	302mm	302mm
Plant 14	300mm	305mm	305mm	305mm	305mm
Plant 15	300mm	311mm	311mm	311mm	311mm
Average	300mm	307mm	307mm	307mm	307mm

Use the graph below to plot the results of above observation. bamboo growth statistics

Conclusion

The hypothesis is proven to be true. Watering bamboo plants with sea water causes a stunted growth or kills the plant.

Sea water is sometimes use to put out forest fires. It may help to put out fires but in turn, adversely affects the growth of the plants that survive the fire. It is advisable to use fresh water if it is available.

Also consider

What would happen if the experiment was varied by using brackish water or water from freshwater lakes or ponds?

The experiment can be repeated using different plants such as bean sprouts, radishes and other fast growing plants.

References

Bamboo - http://www.en.wikipedia.org/wiki/Bamboo

Can you water plants with salt water - http://www.ehow.com/facts_5509396_can-water-plants-salt-water.html

Osmosis - http://en.wikipedia.org/wiki/Osmosis

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