What Happens when Wood Absorbs Water?
Think About It!
When it rains for several days, some of the wooden doors inside my house are hard to open. Why? The doors did not get rained on.
In the video, toothpicks are broken and arranged so that when the broken parts get wet, the toothpicks move forming a star shape. How does the water cause the toothpicks to move? Why were the toothpicks broken?
Hygroscopic is a term used to describe the characteristic of a substance that attracts water. For example, spilled table salt turns into tiny pools of water if the humidity is high. For an explanation for this toothpick activity, see Hygroscopic.
While the star activity is science related, I use science activities to teach children and adults Bible stories and Christian Principles. The star activity is one of the activities in “Hands-On Bible Explorations.” It is a perfect fit for the Christmas story–Bethlehem Star.