Photosynthesis Dry Lab

                                                               PROCEDURES

 Step # 1- First, gather up all of your materials which are three test tubes, bromothymol  
           blue, two aquarium snails, one aquarium plant, two elodea plants, pond water, and a lamp.

 Step # 2- Next, fill a test tube with 30 ml of pond water and sit it on the counter for twenty minutes.

 Step # 3- Then after twenty minutes is up, add 35 ml of bromothymol blue to the test tube with  
          the 30 ml of pond water.

Step # 4- After that, wait twenty minutes and record your results.

Step # 5- When twenty minutes is up, record the color that you got and it should be a blue-green color.

Step # 6- Then, add an aquarium snail to the test tube.

Step # 7- Wait twenty minutes, and record your results.

Step # 8- After twenty minutes is up, record the color that you got and the color should have changed to  
          a yellow color.

Step # 9- Then add 30 ml of pond water, 35 ml of bromothymol blue, and an aquarium plant to another  
           test tube.
 
Step # 10- Wait twenty minutes, and add an elodea plant.

Step # 11- Then leave it under the lamp for it to get light for thirty minutes, and then record your results.

Step # 12- When thirty minutes is up, record the color that you got and it should be a blue-green color. 

Step # 13- After that, add 30 ml of pond water, 35 ml of bromothymol blue, an elodea plant, and 
          an aquarium snail to another test tube.

Step # 14- Then leave it under the lamp for it to get light for thirty minutes and record your results.

Step #15- When thirty minutes is up, record the color that you got and it should be a blue-green color.

Step # 16- After that, leave it in the dark for three hours.

Step # 17- After three hours is up, record the color that you got and it should be a yellow color.

Step # 18- When you are all done with the lab, clean up your mess and put your materials away.



  The fact that bromothymol blue is a blue-green liquid which changes to a yellow color in acid and back to blue-green when returned to a neutral pH explains the observation that water plus bromothymol blue plus an aquarium snail turns yellow. The fact that carbon dioxide plus water yields sugar and oxygen when chlorophyll and sunlight are presesnt explains the observation that water plus bromothymol blue plus elodea, an aquarium plant, is blue-green in light. The fact that sugar plus oxygen yields dioxide plus water and energy explains the observation that water plus bromothymol blue is blue-green. The fact that green plants photosynthesize in the light and respire all the time explains the observation that water plus bromothymol blue plus a snail plus elodea is blue-green in light and yellow when left in the dark for three hours. The fact that animals respire explains the observation that water plus bromothymol blue plus a snail plus elodea is blue-green in light and yellow when left in the dark for three hours.The fact that carbon dioxide in water produces carbonic acid explains that water plus bromothymol blue plus an aquarium snail turns yellow.