Friday, March 29, 2013

Surface Tension Experiment

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I came across this simple science experiment for preschoolers on Carrots Are Orange and just had to give it a try!  There's a good description on the original post about how it works, but here's the gist: when a finger is dipped in the dish soap and then placed in the pepper-covered water, the pepper will move away from the finger.

F grinding up some pepper with her two science assistants

  • Large glass bowl
  • Water
  • Dish soap
  • Pepper
My niece F was having a sleepover at our house all weekend, so I set up this simple experiment for all three kids to check out.

The setup
After explaining what the experiment was about, F started grinding up the pepper.

Grinding pepper
I encouraged the kids to dip their fingers in the pepper water to see what would happen.  F reported, "The pepper sticks to my finger."  J was fascinated by the pepper, "Oooh, pepper!"  And K...well...he soaked his hand in the pepper water and then licked it off his hands.  A science experiment with a toddler isn't successful until the toddler tastes something.

F and J then dipped their fingers in the dish soap and tested out what would happen now.  The pepper will move away from the dish soap, as seen below, which F thought happened "because it's magic."

The experiment didn't end there though.  J dumped the rest of the dish soap into the bowl.

Dumping in the dish soap

K then started using the mixture to clean the table, which was a bonus since the table was covered in little kid fingerprints.

Clean, clean, clean!
Then J and F mixed the soap and water vigorously to make some bubbles.

Mixing bubbles
F informed me that this activity was, "A FUN activity!" and asked to do it again.  Unfortunately, we were out of pepper so I guess we'll have to do it another day.