Kylie, Cassandra, Omer, Kauser

December 11th, 2017

Ms. Meneghin

Biology Honors

Radical Conditions for Photosynthesis

Research Question: “Which type of liquid do plants best photosynthesize in?”

Background Information: Before performing our experiment, we knew the causes and effects of photosynthesis. From previous experiments in the planting science packet, we saw that light, water and carbon dioxide are needed for photosynthesis. When designing our experiment, we kept in mind the necessities for photosynthesis in order for it to be successful and accurate.

Hypothesis: We hypothesized that if we were to test 4 different liquids (fish tank water, tap water, saltwater, and a sports drink) that the fish tank water be the best liquid for photosynthesis. In nature, fish tank water water (which is similar to pond water) is the environment where plants seem to thrive the best in.

Materials:

• 4 cups (big enough to hold 25 mL of water)

• Saltwater (to replicate ocean water) with 3.5 grams of salt/100 mL of water

• 25 mL of “Pond” water that was from the fish tank in the classroom with a plant

• 25 mL of Tap water from the sink

• 25 mL of a Sports Drink (we used blue flavored Powerade)

• Light source (we used a white light lamp)

• Spinach leaf disks

• 2 drops of Soap

• Syringe

• Hole Puncher

Procedure:

1. Fill the “pond” cup with water from fish tank, and place a small piece of kelp in it. (25 mL)

2. Fill tap cup with tap water with 25 mL of water

3. For the saltwater cup, pour 100 mL of water into a beaker and mix with 3.5 grams of salt to create salt water replicating ocean water. Then pour 25 mL of the solution into the cup.

4. Fill cup with 25 mL of blue powerade

5. Once cups are filled, cut out 40 spinach leaf disks using hole puncher

6. Fill a syringe with 10 leaf disks and 3 mL of liquid from a chosen cup. Pull down the plunger while keeping your thumb on top of syringe. Release plunger and your thumb simultaneously. You will hear a popping sound. Repeat this vacuum action until the leaf disks have sunk. Then pour the disks back into the cup. Repeat this action, once for each cup.

7. Once leaf disk are in cups, place under white light for 3-4 minutes

8. Once time is up, remove cups and observe and record how many disks floated to the top and the amount of bubbles inside of the cup.

9. Repeat Procedure Steps 1-8 10 times total to obtain all of your data

Independent variable:

• Liquid

Dependent variable:

• Number of leaf disks floating

• Bubble (oxygen) production

Experimental constants:

1. Light (brightness and time in light)

2. Amount of liquid in each cup

3. Number of leaf disks in each cup

4. Amount of soap in each cup

5. The size of the cups

6. The environment the cups were left in

Control:

• The amount of liquid each cup received

• The “environment of the cups” (under lightbulb)

• Amount of leaf disks placed in each cup

Data:

After collecting all of our data, we concluded that fish tank water made the leaf disks photosynthesize the most.

Documentation:

Analysis: We noticed that pond water had the most bubble production and floating leaf disks, then tap water, then salt water and PowerAde. We took note of things that may have had impact on the experiment. PowerAde consist of dyes which blocked light, and could have contributed to the small amount of disks floating. Also, tap water had little air bubbles prior to inserting the disks (since this came from a faucet that had high pressure build-up), and even with the soap,  this could have allowed leaf disks to ride to the top of the cup. Also, there are some plants (like those in the ocean) that may require water with high-salinity; spinach has a moderate-high tolerance to salt, but there are other forages that have a higher tolerance rate. In addition, fish tank water had an aquatic plant in the cup, which could have contributed to the oxygen production making that cup the most successful.

Conclusion: After analyzing our data, we found that the fish tank water had the most leaf disks float, thus plants in fish tank water photosynthesize the best.

Hi everyone:

It looks like you have finished your experiment.Thank you to you and your mentor for all your hard work.

Best wishes,

Laura

Planting Science Analysis Questions

14a.) Our research question was “What kind of liquid do plants photosynthesize the best in?”

14b.) The only change we made in our experiment was adding soap to each cup. Originally we weren’t planning on putting soap in any of the liquids. However as time went on we were advised to try adding in a drop or two to each cup in order to prevent the leaf disks from immediately rising.

14c.)

14d.) A sentence summarizing our claim is : Pond water is the best liquid for plants to photosynthesize in.

14e.)  Our data helped explain the biological process of photosynthesis because the data was quantifiable. The equation for photosynthesis includes the production of oxygen. We observed bubbles forming in our cup and the number of disks floating, thus proving that the leaf disks went through photosynthesis.

14f.) During our trials, we noticed a few unusual things that occurred and needed to make a few adjustments in order for our data to be more valid (keeping in mind that human error cannot be completely prevented). We had to use leaf disks instead of leaves so it is easier to observe photosynthesis. Also, we needed to add soap to our cups in order for the disks not to ride on the bubbles and our soda solution (Gatorade) started producing bacteria which may have interfered with the disks trying to photosynthesis.

14g.) If we were to do this experiment again we would make sure to regularly change the Powerade. Additionally we would obtain actual pond water instead of water from our classes fish tank and real salt water instead of having to make it.

14h.) We have nothing additional we would like to share with our mentor. We wish him the best of luck.

Hi Nick, thank you for taking time out of your days to help us with this experiment. Your suggestion that we test our experiment  with a sports drink was a great idea! I learned that leaving powerade with spinach disks under a lightbulb create this goopy stuff. It was a fun experiment and we couldn’t have done this if you didn’t help us with our experiment!.

Thanks again,

Omer

Hello

Thank you for taking the time to help us with our experiment. Suggesting that we find an alternative to the "dirty water" was good since our classroom has a fish tank, so we were able to replace the water every trial. I learned that pond water is the best liquid for a plant to photosynthesize in. This is useful to know since the school's environmental club may start an aquatic garden with fish in it. Thank you again for everything.

Best of luck!

Cassandra

Hi! First off thank you so much for taking your time out to talk to us. You were the one who gave us the idea to use Poweraide and without your suggestion our experiment would have been radically different. During the course of this experiment I learned how to properly make salt water. Again thank you for your help and I wish the best for you in the future. 

Kauser

Hi, I would like to thank your for your time and suggestions towards our experiment. Your ideas were very helpful!! I learned that plants photosynthesize best in pond water. I wish you the best in all of your future experiments!!

Kylie  

Hi team!

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Thank you for your patience and cooperation!

We just completed another trial;

Pond water has 4 floating, saltwater has 4 and tap water has all 10. We noticed that Gatorade has all 10, but we suspect that this is invalid since the amount of liquid decreased. We went from having 75 mL of Gatorade to having approximately 35 mL. It must have evaporated over the course of the experiment. This was a result of human error.

The white stuff was bacteria growing in our cup

Today we found a slime-like liquid growing in our Gatorade. We believe it is because we have not changed the Gatorade throughout the experiment unlike the waters which we have regularly changed. Furthermore pond water did the best in creating photosynthesis. Then tap water was doing okay, and saltwater was second in last. Naturally the worst at creating photosynthesis was the Gatorade.

Radical Radishes

Also, we just found out that there is white stuff growing in out Gatorade!!!! We think this is because we have used the same Gatorade throughout the whole experiment.

Radical Radishes

Our biology teacher has some concerns about our project. At first, we didn't put any soap in the tap water and she told us to add 1 drop of soap, but we added 2. Will this have an affect on our project?

Radical Radishes

This is our 4th time performing the experiment.

Tap water, pond water and saltwater all had the disks float up. However, the tap water had the most bubbles and we realized that the tap water has compressed air, which could have let the disks ride along on the bubbles to the top. Otherwise, the only variable that we are changing is putting a drop of soap in the water so they can't ride on any air bubbles that might be present.

We just checked out results; the gatorade cup had no floating disks while the other three cups (all with water) had their leaves floating. There was evidence of O2 production in the saltwater.

Hello, thanks so much for the information. It sounds like you all have thought up a very interesting experiment! I look forward to seeing your results. You mentioned that you believe that dirty water will be the best performing. I was wondering if you had any thoughts about what it is in the water that would help to make the plants photosynthesize?

In addition, we are using 10 leaf disks per cup in order to facilitate the process of measuring the amount of photosynthesis taking place (i.e. oxygen bubbles)

We are using 3.5 grams of salt for 100 mL. 75 mL of saltwater went into the cup. We are using spinach leaves, not plants

We are thinking of making a few adjustments to the experiment: we are going to use "fish tank" water to try and replicate the pond water (dirt, plant, etc.)

The doc asnwers these questions:

10a. What is your research question?

10b. What conditions, plants, treatments, or other variables will you be changing in your experiment?

10c. What conditions will you keep the same throughout your experiment?

10d. Describe the steps you will follow to complete your experiment.

10e. What will you measure? What data will you collect?

10f. How will you present your data to others (charts, graphs, photos, and so forth)?

10g. What do you predict will happen in this investigation? Why do you think this?

10h. Describe how your experiment tells you something about plants in the world

Hi all,

Thanks for answering my question. Your question sounds like an interesting one. One thing that I would warn is that using "dirty water" might be hard to keep consistent over multiple replicates. Similarly, I would encourage to pick a certain amount of salt to add to the water to keep it consistent. Another possibility, depending on what you have available, would be something like a sports drink.