Photosynthesis "Dry Lab"

What you will need: One snail, 5 drops of bromothymol blue, a test tube of water,and an aquarium plant.

1. combine five drops of bromothymol blue with water in the test tube.
-Record your observations on what the water looks like.

2. After you have recorded your observations, drop the snail into the now blue-green water. After one minute discribe what the water looks like.

3. Next,remove the snail and combine the bromothymol blue, and drop in the aquarium plant.
What color is the water with the objects in it in the light look like?

4. Combine the bromothymol blue, plus the snail.
-Record what it looks like in the light
-next put the experiment in the dark for about three hours (closet, dark room)

5. Take your water out of the dark room
-What is the color of the water now? why do you think the water did what it did?

Conclusion:
1. Water plus bromothymol blue is blue-green because bromothymol blue plus blue-green liquid changes to a yellow color.
2. The aquarium snail turns yellow because animals respire carbon dioxide in water produces carbonic acid and that acid changes the color yellow.
3. Bromothymol blue and the plant in water turns blue-green in light because water plus sugar and oxygen turn a blue green when light is present. Green plants photosynthesize in the light and respire all the time.
4. Green plants photosynthesize in the light all the time so if the plant is in the dark for three hours the snail changes to yellow because the plant has nothing to give energy out to in the dark.  With out the carbon dioxide in water cannot yield sugar and oxygen, therefore there is no chlorophyll and sunlight to make the plant green.


Questions:
1. Can other animals that breath through their skin do this in an experiment?
2. Why is it that only carbon dioxide turns the water yellow?
3. Do all plants breath under the water too?