Photosynthesis "Dry Lab"

Materials:
3 Aquarium Snails
5 medium size beakers
Heat lamp
100 mL of water per beaker
BTB (bromothymol blue)
3 Elodea (aquarium plant)

Procedure:
1. Take all your materials out.
2. Put 100 mL of water in all four beakers
3. Take Beaker 1 and put 15 drops of BTB in the beaker. Let the beaker sit for a couple minutes until you notice changes.
4. Take Beaker 2 place 15 drops of BTB
5. Place the snail into the beaker
6. Observe what happens & record it.
7. Take Beaker 3 and place 15 drops of BTB into the breaker with the Elodea
8. Place under heat lamp until you notice changes.
9. Record changes
10. Take Beaker 4. Place 15 drops of BTB in the beaker along with the snail and Elodea
11. Place under light until you observe changes.
12. Record them.
13. Take the last beaker (5) and place 15 drops of BTB in the beaker along with the snail and Elodea.
14. Place in the dark for three hours.
15. Observe changes.

This is probably what you noticed:
Water plus BTB is blue-green
Water plus BTB plus a snail turns yellow
Water plus BTB plus Elodea is blue green in the light
Water plus BTB along with the snail and plant is blue-green in light and yellow in the dark after three hours.

This is why:
Carbon dioxide in water produces carbonic acid.
BTB is blue-green in liquid which changes to a yellow color in acid and back to blue-green when returned to a neutral pH.
Carbon dioxide plus water yields sugar and oxygen when chlorophyll and sunlight are present.
Animals respire.
Green plants photosynthesize in the light and respire all the time.
Sugar plus oxygen yields carbon dioxide plus water and energy.

Each fact above has something to do with why you noticed the changes you did in your lab. Photosynthesis is important for plants to get their food. This is important for us because we eat plants to get our energy.