Dry Lab

Photosynthesis Dry Lab

In this “dry lab” you will be working backwards from what you would normally do in a lab situation. In this case, you will be given a set of observations that were made in a lab and you will be asked to reconstruct the procedure that could have generated this data. You will also be given a set of facts that you will use to explain this set of observations in the analysis and conclusions section of your lab write-up. As you create the procedure for this lab, please remember all the rules that you have been learning about good experimental design.

Your lab report begins below. Fill in the missing sections of the lab report using the observations and facts given. You may assume that you have access to as many test tubes, snails, Elodea plants, light sources, dark places, and as much pond water and BTB as you need.

Make your own copy of this Google Doc and edit the lab report that begins here:

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My Most Awesomest Photosynthesis Lab Report

by

Purpose:

Background Facts:

• Carbon dioxide in water produces carbonic acid.
• Bromothymol Blue (BTB) is a blue-green 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.

Hypothesis: If we add bromothymol to water than the liquid will turn a blue-green color but if we had different things to the mixture it will turn different colors.


Materials: Water

Bromothymol Blue (BTB)

Aquarium snail

Elodea (aquarium plant)

Procedure:

2. The first thing we do is add bromothymol blue to the water and see what color it is. Then we add an aquarium snail with the bromothymol blue to the water in another cup and observe the color change. Next we get another cup and add bromothymol blue and elodea the aquarium and observe the color in light. Finally we get another cup and add bromothymol blue, a snail and elodea and leave it in the dark for three hours. When the three hours are up we observe the color. 

Observations:

1. Water plus bromothymol blue is blue-green.
2. Water plus bromothymol blue plus an aquarium snail turns yellow.
3. Water plus bromothymol blue plus Elodea (an aquarium plant) is blue-green in light.
4. Water plus bromothymol blue plus a snail plus Elodea is blue-green in light and yellow when left in the dark for three hours.

Analysis and Conclusions:

1. Water plus bromothymol blue is blue-green because...

2. Water plus bromothymol blue plus an aquarium snail turns yellow because...

3. Water plus bromothymol blue plus Elodea (an aquarium plant) is blue-green in light because...

37. Water plus bromothymol blue plus a snail plus Elodea is blue-green in light and yellow when left in the dark for three hours...