Pine cones and humidity

This is a very simple activity - all you need is a pine cone and somewhere to hang it outside.  My son likes to bring a souvenir pine cone home when we've been on forest walks, and our neighbours have a tree that produces huge pine cones which fall into our garden. As a result, we've amassed a collection of pine cones of various shapes and sizes.  As it's almost world meteorological day (Monday 23rd March), and lots of people are isolating at home and may have a pine cone or two to hand, I thought now would be a good time to post this, even though we actually did it a few weeks ago.

Pine cone scales open when it's dry as this is better for their seeds to disperse, and they close when it's damp. Pine cones can therefore show us whether it's dry (open) or humid (closed). One of the large cones sat on our doorstep on and off, and we noticed it opening and closing. It often sat in a pool of water though, so it stayed closed even when the weather was dry. I therefore suggested that we chose some pine cones from our collection to hang in the garden to show us how much water is in the air (i.e. how humid it is).

My son picked 4 pine cones of varying size. We hung them in our pear tree in our garden with some garden twine.  They were dry from being inside the house so it was easy to wrap twine inside their scales. It was quite damp outside and my son noticed the pine cones closing over the next couple of hours as they adjusted to the outside air.  Our garden isn't huge so he can see the pine cones from indoors which is handy for being able to observe them even when the weather is really horrible!

Pine cones open in dry weather

We've since lost a couple of the smaller pine cones in a recent storm (which also wiped out the fence in the picture), but the remaining pine cones are still a nice talking point about the weather when the small boy sees them!  If you'd like to try another weather-related activity, we also made a rain gauge last year from a plastic bottle, and it's still going strong (when we remember to empty it).