Science Buddies: "Ask an Expert"

My 3rd grade daughter completed the How Much Worm is a Worm project and was a winner at her school. Before she goes to the next level we were talking about doing some additional trials. But we had 2 major problems with the original experiment First, we couldn't tell whether the worms were regenerating or not, even with a magnifying glass. We're not sure what we're looking for though. Do we need a microscope for this and how would we get the worm to lie still anyway? Second, we couldn't figure out how to accurately measure them since they constantly change length. Can you provide any help? Thanks in advance!!

Hi,

I think you are doing this project. And, I think it is a good idea to do an additional experiment before moving to the next level of competition.

https://www.sciencebuddies.org/science- ... p011.shtml

Yes, I agree it is difficult to measure earthworms because they are so wiggly. If you have another month, you could try repeating your experiment and try weighing the earthworms before and at 1 week intervals. This would require a sensitive balance that would weigh to the closest 0.1 or 0.01 grams. If this is not available, then do your best to measure their length, maybe the maximum length observed during one minute of observation. Trying to do some type of measurement will definitely enhance the project. Or, maybe you could try taking a photograph to record results.

The science buddies project says it’s OK to use bait shop earthworms for this project, but, in my experience it’s much better to do earthworm projects with live healthy worms from the garden (if you are in a warm climate) or from an earthworm supply source. If you do use bait shop earthworms, try to make sure they are as fresh and healthy as possible. If you do start out with very healthy worms, you will get results much faster.

Also, make sure that all conditions are controlled, except for cutting the worms. That means that the soil, volume, temperature, food, moisture, and light should remain constant. And it would be a good idea to measure these parameters to verify the conditions of the experiment. But do skip the additional measurements if it’s too overwhelming for you daughter. What is your daughter feeding her earthworms?

Your daughter should learn as much as possible behind the science of her project and understand the beneficial implications of research in this area. Here is an article on this subject; you will have to read and explain to your daughter. I’m sorry; I couldn’t find a suitable article at her reading level. Let me know if you need help with this.

http://www.isj.unimo.it/articoli/ISJ219.pdf


Donna Hardy

Thanks for your insights and the article. We were able to find a scale at out local science center and they are allowing my daughter to use it throughout her project. They said that in addition to weighing them we would need to count segments to verify if any regeneration had occurred because a weight increase could be attributed to something else like eating. Since we can't get them to lie still long enough to count segments, we're going to try taking a picture close up and counting them that way. Or is there anything that would knock them out for a few minutes without harming them?

The only food we have given them is 2 small pieces of apple peel in each cup. I wasn't really sure what to feed them but thought that might be ok.

Hi,

It sounds like you are making progress. Counting the segments is a good idea, and taking a photograph that you can use to record results later would work. I would not recommend doing anything to knock out the worms; this might affect their ability to grow and regenerate.

You can feed your earthworms a little oatmeal, coffee grounds, or Purina worm chow, sprinkled on top of the soil. You can add a few crushed egg shells as a source of calcium. They will come up to the surface to eat and they like to eat a little every day. Worms must be kept moist at all times, but not too wet.

http://growyourownearthworms.blogspot.com/

http://www.biologyjunction.com/earthworm%20facts.htm

http://www.biologyjunction.com/earthwor ... regenerate

http://en.wikipedia.org/wiki/Oligochaeta

What type of earthworm is your daughter using? One suggestion, if she is interested, is to find the scientific name of the earthworm. Scientists like to use scientific nomenclature when describing their work, as this avoids the confusion caused by using common names.

Donna Hardy