DNA Replication Activity/Snack

I bet someone could come up with a better version of this activity, with foods that fit together more…naturally? I felt like there were things that would go perfectly together (like, I don't know, olives and fingers :)) but I just couldn't think of what they were! Anyway, I wanted the children to demonstrate the way DNA "unzips" and replicates, so I came up with this snack/activity. 

Before you start, learn about how DNA replication works. We really liked this video showing the process.

Then, you need four different snack foods to be your "bases". They should fit together in pairs somehow. I used square pretzels and square soda crackers for one pair (Adenine and Thymine, perhaps) and elliptical wheat crackers and slices of cheese for the other pair (cytosine and guanine, say). I tried to cut little semi-circle-shapes out of one side of each piece of cheese, so the cheese and the crackers would fit together like puzzle pieces. (Just to demonstrate more visually that they were meant to fit together.) You put a bunch of each of these "bases" onto a tray to represent the bases that are floating around free inside the cell's nucleus.

Next, for each child, I made a little tray holding one "strand of DNA." It had several base pairs lined up to make a strand (or a gene, perhaps).

Then I just had each child show me what would happen as the DNA replicated. They had to "unzip" or slide the strand apart, and then find the matching bases to complete each side of the unzipped strand. When they were done, they could see how their new DNA strand was an exact copy of the original. And then, of course, they could eat it. Yum! :)