With just toothpicks and water, you can wow your children with this toothpick star trick plus teach them about capillary action.
Simple science experiments that make kids think magic exists are the best ones. Not only can your kids do the science trick by themselves, they can also put on a show for friends and family.
This water toothpick star trick is so easy that even preschoolers can perform it. The most delicate part of the experiment is bending the toothpicks so that they can fold in half, but not fully break apart. Elementary school students should have no problem with this, but you may need to help the younger kids with setting up the star.
You can use a dropper, syringe, or even a drinking straw to add the water to the plate. Just make sure that you add the water in drops slowly so that the toothpicks start to straighten themselves. If you add too much water at once, the toothpicks will float apart and you will loose the star shape.
With that in mind, let’s get on to amazing your kids with this fun toothpicks science project!
Water Toothpick Star Trick
- 5 wooden toothpicks
- A dropper, syringe, or drinking straw
1. Gently break the toothpicks at the middle so that they bend in half but do not break completely into two pieces.
2. Arrange the toothpicks on the plate so that their ends touch each other. The toothpicks should create a five-pointed star pattern.
3. Suck up some water with the dropper (or syringe or straw).
4. Slowly add water to the middle of the toothpick star. You want to make sure that the water touches all the toothpicks so that all the broken ends start absorbing the water.
5. Continue to add drops of water to the plate until the toothpicks open up into an open star shape.
How Does the Toothpick Star Trick Work?
Note that for this experiment, you need to use toothpicks made out of mostly dry wood. When you break the toothpicks, you cause some of the wood fibers to stretch and bend. Then when you add water to the plate, the exposed wood fibers absorb the water and start to swell.
As the soaked wood fibers start to expand, the toothpicks straighten and the pointy ends of the toothpicks push against each other. The result is the inside of the star opens up into the familiar star shape.
But how does the wooden toothpicks absorb water?
Similar to what we saw in the celery and food coloring science experiment, the hollow tubes within the wood cause the water to travel to the other parts of the toothpick.
You see, the forces of cohesion (water molecules like to stay together) and adhesion (water molecules also like to cling to another surface) causes water to be “sticky.” Thus, water molecules act like little mountain climbing teammates and climb up the hollow tubes in the wooden toothpick together, pulling each other along.