Purpose: The purpose of these experiments is to compare the two processes of photosynthesis and respiration and to find out what they do.
Equipment: Photosynthesis Disposable gloves, lab apron, safety goggles, two 5 cm sprigs of elodea, three 250 ml flasks, water, Bromothymol Blue (Ph indicator), rubber bands, drinking straw, plastic wrap, 100 ml graduated cylinder Respiration Disposable gloves, safety goggles, lab apron, 250 ml flask, 100 ml graduated cylinder, phenolphthalein solution, pipet, drinking straw, water, clock, sodium hydroxide solution Procedure: Photosynthesis Put on safety goggles, lab apron, and gloves. Label the flasks #1, #2, and #3. Put 200 ml of water and 20 drops of Bromothymol Blue into each flask. Put drinking straw in flask #1 and blow into blue solution until it turns yellow. In flask #2 do the same as in flask #1. Put one elodea sprig into flask #1 and the other one into flask #3.
Do nothing to flask #2. Cover flasks with plastic wrap and secure with a rubber band. Leave flasks in a well-lighted area and leave them overnight. Record observations.
Respiration Put on safety goggles, lab apron, and gloves. Put 50 ml of water and four drops of phenolphthalein to the flask. Using the drinking straw, gently blow into the solution for 1 minute. Add the sodium hydroxide one drop at a time, and gently swirl the flask. When the liquid turns pink, stop adding drops. Record the number of drops you used. Run around for 2 minutes and repeat from blowing into the solution with a straw.
Data: Photosynthesis Flask # Thursday Friday Monday 1 Yellow Clear Clear 2 Yellow Yellow Yellow 3 Blue Blue Blue Respiration Before exercise After exercise 15 Drops 30 Drops There was a 100% increase in the amount of drops it took to turn the solution from acidic to basic.
Analysis and Conclusion: Photosynthesis: I expected flask #1 to turn blue.
I expected flask #2 to stay yellow.
I expected flask #3 to stay blue.
Some factors that affected the experiment were the amount of sunshine, temperature, and amount of CO2 in the room.
Some factors that affected the CO2 were the amount of plastic wrap, how many people were in the room, and the rate of photosynthesis.
Respiration: The increase in drops indicates that a faster heartbeat means that there's more CO2 being breathed out because you breathe more oxygen in so you have to breath out more CO2.
However, I would expect that a decrease in your heartbeat would mean a decrease of CO2 because you breathe in less oxygen.
Factors that might contribute to rate of respiration are: ÃÂ· Height - the heart works harder when one is taller.
ÃÂ· Weight - the heart works harder when one is larger.
ÃÂ· How fast you run - if one runs slow, then the heart rate doesn't increase as much as it would if he/she would have run faster.
ÃÂ· Good shape or bad shape - if one is in good shape then he/she is used to it, but if one is in bad shape then he/she isn't used to it.
Factors that might change experiment are: ÃÂ· The length between running to gain your heart rate and blowing into the straw.
ÃÂ· Didn't test the Ph of the water before; the Ph could have been higher or lower.
ÃÂ· How tired person was before experiment; if the person was really tired before the experiment, then his heart rate will decrease because he will be tired and will run slower than if he was fully energized.