MAX: I don't think I'm ever going to like celery, Mom. It gets that yucky, rubbery texture. I don't like it.
ALINA: It's not always rubbery. Usually, it's pretty crisp and crunchy. You can keep it from getting that way, you know.
MAX: I don't know much about celery, actually. Why does it get rubbery at all?
And thus he threw down the gauntlet on New Year's Eve. Not one to ignore shiny metal objects on the floor of my kitchen, I told Max I didn't know the answer, but would love to help him find out.
We discovered that celery stays firm and crunchy as a result of water pressure within its cells. When celery dries out, it loses water through evaporation. If you put a stalk of fresh celery with leaves on it in an empty glass before you go to bed, the celery will be droopy and rubbery in the morning. However, all it takes is adding some water to the glass and waiting a few hours to see your celery perk back up. The cells absorb the water to replace what they lost through evaporation.
Before we left for the park, we set out a stalk of celery in a glass without water and a stalk of celery in a glass with water. When we returned, sure enough, the water-endowed celery was thicker, firmer, and happier than the water-starved celery, who looked quite peaked.
MAX: Cool. So the celery cells suck it up. But I don't see how because it doesn't have an open stem, like flowers do.
Right. Time to play with celery. We took the celery stalks out of the glasses and Max cut an inch ("the white part", in his words) from the end of stalks. Then we held them up to see how the water was absorbed.
MAX: What are those dots?
MAX: I get it! See Mom, the one that didn't get water has really small capillaries because they are dried up and smushed together but the other one has big capillaries full of water.
Seeing the capillaries wasn't enough- Max needed to tear apart the celery and trace the capillaries up through the stalks. As he played around, I learned that chefs at nice restaurants like to soak celery in water before serving it to maintain that crispy, fresh texture.
MAX: So you can keep celery from being rubbery by giving it water or putting it in water. But why don't we keep our celery in water then? Why do we put it in the fridge? Does the fridge give it water vapors?
We couldn't find an answer to that, so we added it to our ongoing questions. We did, however, learn some more specific tips for keeping celery crisp in the fridge- tips that led to all kinds of questions about the nature of aluminum and how paper towels stay wet (rather than drying) in the fridge.
Max wanted to do the classic celery and dye science experiment (with his own twists, of course). He put 5 drops of blue food coloring in one glass with water and 4 drops of red food coloring in the other glass with water.
MAX: I want to see if a different amount of dye makes the color more bright.
I told him that having multiple variables in an experiment could make it hard to tell which played a casaul role in the experiment's results. Max nodded.
MAX: Yeah, but I still want to try. I can write down all the variables and we can do it again if it doesn't work.
I'm glad he sticks to his guns when curious.
MAX: The glasses aren't the same and we didn't measure how much water we put in each glass, so the water volume might be a variable. The colors might be variables too. Maybe red is absorbed faster than blue. Plus, I think the one with the big capillaries that spent time absorbing water while we were at the park will absorb more dye.
ALINA: I don't. Why do you think so?
MAX: I don't know. I just do.
I guess we'll find out next year.