Science Buddies: "Ask an Expert"

Hi,

I'm trying to design an experiment that would test the effect of pH levels and Dissolved oxygen on the growth of aquatic plants and fishes. I was wondering if anyone could suggest a type of plant and/or fish that grows significantly after a two week period (or a bit longer than that but not over three weeks)? And I was also wondering how I can vary pH levels or Dissolved oxygen levels in water. Like, what do I add or mix into water or something? Please help, I'd appreciate it so much

Hello,

For this experiment, I would recommend that you use plants rather than fish. You do not want to harm the fish during the experiment by stressing them and causing them to die. You can buy aquatic plants and pH kits at a pet store that will allow you to adjust the pH of your water in your different aquariums. How many different pHs do you want to test and how will you choose them?

Check out this link for the dissolved oxygen experiment you want to perform:
https://www.sciencebuddies.org/science- ... ?from=Home

Hope this helps,
Mary

Hi purplesky,

I agree with Mary that you do not want to risk harming any fish. That said, if you do a little research online and at aquarium shops, you may be able to do part of your experiment with a pH range that will not harm your fish. Guppies and goldfish are known for being hardy animals, and may work for your experiment. However, you do need to be careful not to stress your fish. There are aquarium guides that will tell you what pH range is tolerated by these animals.

Good luck!

Heather

Hi again,

So I've decided to run the experiment on goldfish. I've been researching on them and they seem to be able to survive in a tank without water change for about two weeks. So I'm going to put them in there for two weeks and put them into the school's fish pond after the experiment. I was just wondering if there would be significant signs of growth after two weeks, like some weight gain maybe? Since I don't think they grow longer in that short amount of time

Hi purplesky,

If you get young feeder goldfish, you should be able to see a change over the course of 2 weeks. I think guppies might work even better.

I'm not sure how you would weigh your fish without stressing them, so length is probably the easier measurement.

I hope that helps!

Heather

Hi,

Please see the following link regarding the use of vertebrate animals. You need to make sure that you have the appropriate approvals, if necessary, BEFORE you start your experiment.

https://www.sciencebuddies.org/science- ... mals.shtml

Mary

Hi,

On top of the last link, here is a sample form that might be required by a regional science fair: http://www.societyforscience.org/Document.Doc?id=20. The vertebrate animal form will vary from competition to competition, but that should provide a pretty good example of questions you should be expected to be able to answer. So, when designing your experiment, keep in mind lots of different factors like "cage/pen size, number of animals per cage, environment, bedding, type of food, frequency of food and water, how often animal is observed"

Hope this helps!
Aaron Lin