Science Buddies: "Ask an Expert"

Hello, I'm a student who is trying to do a science project on if an egg shell will increase in permeability depending on the temperature. I am not sure where to start with this project, like the procedure. I am thinking that an egg shell will not increase in permeability depending on the temperature because temperature will not enlarge or shrink the pores of an egg shell. How will I be able to try and prove this? I would also like to know if I would need access to a laboratory or laboratory materials because I am not sure how I will control the temperature for this experiment. Would I need certain materials that are not at home materials? Thank you.

Hi, that's an interesting question and I would like to know the answer. Of course, it depends on what temperature you choose and what compound you pick to measure permeability. Another variable is the length of time you keep the egg at the elevated temp. I assume you mean to use raw eggs, because cooking would certainly change the permeability.

As for temperature regulation, aquarium heaters are inexpensive and pretty good at temp control, although I don't know what their highest temp would be. You could use a pot of water on the stove on a low setting if you have an accurate thermometer and are not trying to maintain the same temp for hours.

Have you tried putting eggs in water containing a food color? That might be a good way to measure penetration of a chemical through the egg shell.

If you need more help, post again.

Good luck!

Sybee

Hi, I was researching and found the "How Does a Chick Breathe Inside Its Shell" science project on this website. Would detergent with the food coloring be good to use in this to measure the permeability? For their procedure, it says to put the egg in for 24 hours. I was going to use a thermometer but if it has to be 24 hours for the detergent to break through the membrane, I don't know if it will work out. The aquarium heaters don't seem to go as high as I'd hoped for. The temperatures I want to choose is 0 degrees Celsius and 60 degrees Celsius, are these numbers okay? Thank you again.

I don't know if food dyes will penetrate the egg shell, so you will just have to do an experiment first to find out. Food colors are edible so save the eggs when you break them and you can have them for breakfast.

My hypothesis is that the dye will penetrate the shell and membrane in 6-12 hours rather than 24, but here again, you need to do a preliminary experiment to make sure. Test two eggs with dye at 20C and break one open at 6 hours. if the color has not penetrated through the membrane then check the second egg at 12 hours. Just be sure to put the eggs in the dye solution early enough so that your 12-hour time point is not at 3 am!

As for temperature to test, I would use the temp of your fridge, which is usually around 4C, for the low temp, then do room temp for the second temp, and finally for the high temp I would do 45-50C, as I think 60C might be hot enough to begin to denature egg proteins and this might interfere with the diffusion of the dye.

And you are right, the aquarium heaters won't go up to 45C, so you will have to try and get a water bath on the stove to the right temp and hold it there. Just be sure to use a large volume of water--at least a gallon--so the temp will be more stable. Getting the water to stay at the right temp for 6-12 hours is going to be difficult. If you have some other way to hold the temp of a volume of water at 45-50C, like a foot bath, then use that.

For the test at 4C, you will not have to use so much water, as the fridge is pretty good at maintaining temp. Three cups of water in a quart jar should be adequate. Just be sure the water is at fridge temp before you add the eggs. Put the jar way in the back so the temp won't fluctuate when people open the fridge door.

For the room temp test, I would use 1-2 quarts of water with dye to ensure that the temp stays pretty stable.

One other variable we have not talked about is the amount of food color to add to a certain volume of water. I have no idea how much dye to add so you will probably have to do another little experiment to determine the ratio of dye to water to use to see color in the membrane. I think the food color bottles have droppers, so you can count the drops as a way to measure the volume. I would get some one pint canning jars and add the dye to two cups of water at room temp and check the eggs after 6 hours.

You can Google using food color for experiments and maybe find some information about how much to use for a certain volume of water because I really have no idea.

Let me know how you make out with the preliminary experiments.

Good luck!
Sybee

Sorry it took so long for me to reply, thank you for the help. I have done the room temperature test and I am currently waiting on the low temperature test. I have measuring teaspoons and I used 1/2 a teaspoon which seemed to work for it. 6 hours was enough for the dye to penetrate and the room temperature egg is completely dyed blue. For the high temperature test, would a water bath on the stove be a pot of the egg in a pot of hot water? Or would I just have to submerge the egg in dyed water on the stove? Thank you so much again.

I'm glad you got some dye to penetrate--that's a start.

For the higher temp, you want to use a large pot of water on the stove at the desired temp so it stays there and doesn't fluctuate much. Put your egg and dye solution into a smaller container like a glass or jar and put that into the pot, being careful that you have it held securely in the water so it doesn't tip over.

You should put the egg into the pot of water to get it warmed up first, and also have the glass of dye in the pot so it can warm up to the correct temp. When the egg and dye are at the right temp, put the egg in the dye and start your timer.

I predict that the dye penetrates the eggshell and membrane faster at the higher temp, but this is a hypothesis, and it is not proven until you have evidence that confirms it. In regard to that, you really should do the experiment three times to get three independent results that you can average. This allows you to do a statistical test on the data so you can compare the time to dye penetration at the different temps and prove whether the difference is true or not.

Keep posting so we know what happened.

Sybee