In middle school, I needed a science project, and I was bored by the typical baking soda volcanoes and planetary models. A few hours of googling turned up projects that I didn't have the equipment to try. But it so happened that one evening, I was asked to chop some onions, and we had quite a number of them in the fridge. Since we had so many onions, I thought I might use them for my project. After one more search, I found that I could actually extract the DNA from the veggie and spool it like thread. Needless to say, my peers were pretty fascinated.
It takes a little time and some special equipment, but you can do it, too! Onions have large cells and membranes that are pretty easy to permeate with the right mixture and heat, and the DNA, contained within the nucleus, comes sprawling out. You can actually see the shape of it once it unfolds, without a microscope!
But you have to be very careful when you extract the DNA. It's delicate enough that even too much time in the hot water bath ortoo much of a certain compound in the mixture will damage it. The process is long and complicated enough to warrant a whole separate post, but essentially you're chopping the onion, mixing it with a chemical bath at the right temperature to break down the cell membrane, and waiting for the separation to complete. If you want to try it out and impress your friends, or maybe guide your kids through the process, check out the link from Science Buddies below!