Have you ever looked under a pine tree after it rains and wondered to yourself, “Huh, I wonder why I never noticed all those closed pinecones.” And then a couple of sunny days later you pass by and wondered where the heck they all went. Here’s a little experiment to do with your class/after-school/pre-school/own little ones that will help you and the kids understand what happened.
First, you will need pinecones. The very best way to get these little guys is from underneath a pine tree. Doesn’t matter if they are little or big, but they need to be ‘ripe’ woody ones with mature seeds, not the green ones. Take the kids and pick up about ten or so, they can either be wet or dry when you pick them up.
Now that you have them, you need a deep try or a large bowl, something that will hold a little bit of water but will allow the air to get to the pinecones. Throw the pinecones in, after examining each one. If they are dry and open add some water on top of them. Drown them, if you want to, but they need to become quite thoroughly wet. And then watch the magic of nature. In just a few minutes you will notice that the ends of the pinecones will have started to close, protecting the seeds inside the cone. Pretty cool.
After each one is completely closed (the newer ones will do so, but if the cones are a couple of years old they might not close all the way), pour out the water and set the cones out on a dry towel. To help the little fellers along you can get a hairdryer out and the kids can try to dry them out. This process takes significantly longer than the getting them wet part. If you can, set them out in the hot sun for a couple of hours. By the end of the day you will see them open up. Like magic.
Why? Mother Nature is a pretty cool chick. In order to protect the pinecones seeds from drowning in the very wet, the woody husk of the pinecone expands when wet, bows just like a wet board will warp, causing the pinecone to close. What is really cool is that when the pinecone dries out the wood will contract, pulling the cone open again and letting the seeds fly away on the wind to be planted and start the whole process over again.