Billings Public Library Science Activity: Ghost in a Tube

September 11, 2019

SteamFest 2019

Sunday, September 29, 2019

6:00 PM 9:00 PMUTC

Billings Public Library is bringing the TECH Lab to the 2019 SteamFest at Billings Depot on September 29. Kids will learn coding and how to control a robot remotely from a computer with the LEGO Robots that they’re bringing to the festivities. The Library’s Pedal Powered Library will also be onsite at SteamFest.

Billings Public Library believes that STEAM activities and education play a vital part in introducing the next generation to the vast variety of academic and practical topics they can have a career in, and attempts to provide opportunities for youth to discover something they are passionate about.

The Library provides STEAM programming regularly throughout the year, but they’ve also shared with us an activity kiddos can do at home with their families ahead of (and beyond) SteamFest.

Billings Public Library Science Activity: Ghost in a Tube

  • (best for grades K-3)
  • Prep time needed: 1 hr.
  • Time needed for lesson: 1hr. – Introduction of the activity, demonstration, practice, reflection


  • 2 test tubes
  • Cold and Hot Water
  • Index Card
  • Paper and Pencils
  • Food Coloring
  • Funnel


(best if done over sink or newspaper due to mess)

STEP 1: Have students draw three long ovals on their papers. These will represent their test tubes and what they see during the experiment.

STEP 2: In a cup fill halfway with hot water, add a couple drops of food coloring and stir. (Should be pretty dark)

STEP 3: Use funnel to fill one test tube with the colored hot water. Have someone hold the test tube. 

STEP 4: Fill the other test tube with plain cold water. Cover the opening with an index card.

STEP 5: Hold card firm over cold test tube and turn over. Place upside down tube and card over the hot colored test tube. Very carefully pull card away. The water will begin to swirl and mix.

STEP 4: Did you see the ghost? Have students draw what they saw when they pulled the index card away. Then have them draw again after the water is all mixed. What does their process look like? Can they explain what happened and why? As less-dense warm water meets the denser cold water, the warm will rise. Meanwhile cold water is sinking. This process in Convection. Convection is where a warm fluid or gas will rise as a cold fluid or gas sinks. Explain where students will see this in nature. A great example would be cumulus clouds.    

Created by Ashleigh West


SUNDAY, SEPTEMBER 29, 2019 @ 12-3PM

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