Why Do Pine Cones Open and Close?

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Meatball has a certain fascination with pine cones…I have piles of them all over my house. This pine cone science experiment came to be when the question of why do pine cones open and close came up during a painting activity. While painting with pine cones Livia discovered that some of the pine cones that were shut up tight began to open, and so we had to explore.

I was surprised at just how quickly this science experiment developed and what it turned into!

Items Used

Pine Cone Science Experiment: Why Do Pine Cones Open and Close?

Because the paint was wet Livia decided that the pine cones opened and closed due to moisture. We decided to use water because it would be easier to observe changes in than other liquids such as paint.

Exploring How Pine Cones Open and Close

The first thing my kids noticed when the pine cones hit the water was that they float! Since we had some pine cones that were open and some that were closed we had to take a moment to see if whether that affected if the pine cone floated or not. This quickly turned into a sensory soup as Meatball tried to fit all the pine cones into the water container. They also noticed that the round part of the glass acted like a magnifying glass giving us a really neat up close view of our submerged pine cones.

Pine Cone Science Experiment: Why Do Pine Cones Open and Close?

Once wet our pine cones almost immediately closed up. The ones in the cold water closed quicker than the ones in the hot water. As soon as they were closed Meatball would transfer them over to the dry container. It was fascinating to watch them slowly reopen as they dried.

Pine Cone Science Experiment: Why Do Pine Cones Open and Close?

This led to some fun conversations while playing!

The Science Behind Opening and Closing Pine Cones

The scales of seed-bearing pine cones move in response to changes in humidity. When warm and dry the pine cone opens up to release the cone’s seeds. When it is damp or cold, the scales close up.

Pine Cone Science Experiment: Why Do Pine Cones Open and Close?

There was a lot of questions about the mechanics behind the opening and closing of pine cones. When wet the pine cones cells expand, when dried they shrink. We did pull out some sponges to provide a more visual representation of this concept (which at that time I was elbows deep in a water mess and the camera was far far away).

Pine Cone Science Experiment: Why Do Pine Cones Open and Close?

We had an absolute blast with this hands on exploration of pine cones and the following sensory soup. With next to nothing for set up, no large time commitment, and this much fun, we will definitely be exploring this one again. Maybe next time with different liquids 😉

Turn this science observation into a fun at home or in the classroom learning experience with our printable pinecone observation and recording worksheets. This printable packet includes instructions on how to do the experiment, observation recording for before and after the experiment, and a handy dandy K-W-L (know, wonder, learned) chart. We hope y’all have a blast with this!

If your family does this science experiment we would love to see the fun!

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2 thoughts on “Why Do Pine Cones Open and Close?”

  1. Thank you! I have been saving pine cones to create something with them! I learn something new today about open and close!


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