Category: Developing Talents, Learning and Living the Gospel

Duration: 1 session
  • At least two empty soda bottles (the largest you can find!). Other large, clear containers can work too – the height is important here so you can’t use milk or juice jugs because they are not as tall. The taller the better!
  • Lots of small metal items (nuts, bolts, paper clips, thumb tacks, screws, etc.)
  • A few handfuls of styrofoam peanuts or pieces of styrofoam.
  • Pipe cleaners
  • Other assorted random small items, some that float and some that sink (such as clay, plastic bottle caps, corks, LEGOs, etc.). Avoid items that will retain water (so no pom poms, cotton balls, sponges) or break apart in water (paper, food).
  • Tongs (like salad tongs)
  • Towels


  • Cut the tops off of the soda bottles.
  • Remove the label from the soda bottles.
  • Stand it up and measure to find the middle, then draw a horizontal line across part of the middle (this is the “starting line.” (Doesn’t have to be exact.)
  • Right before starting, fill the bottle mostly full with water.
  • Stop watch (app on your phone)
1. Read Matthew 6:24 (No man can serve two masters: for either he will hatethe one, and love the other; or else he will hold to the one, and despise the other. Ye cannot serve God and mammon.). Discuss its meaning.
2. Ask the girls if they have ever heard of the word density. Density describes how much matter is present in an object. Hold up a piece of metal (like a nut) and a small piece of styrofoam that are about the same size, and explain that they have the same volume, but the metal nut has more atoms tightly packed into the same space. That’s why it’s heavier than the styrofoam, which is much less density. Everything around us has density.
3. Point to the water in the bottles. Ask:
  • Does water have density? (Yes.)
  • Do you think the water is more dense, or less dense than the styrofoam? (More dense.)
  • Is it more dense, or less dense than the nut? (Less dense.)
  • How can we test this? Explain that things more dense than water sink, and things less dense than water float.
  • What if we combined the styrofoam peanut and the nut? Would it be more or less dense than the water? (Don’t know yet.)
  • How could we find out? (Attach them together and see if it floats or sinks.)
  • What would happen to something in water if it were the same density as water? (It wouldn’t float or sink.)

4. Tell the girls they are going to be working in teams of 2-3 to make a “flinker” – an object that doesn’t float or sink, but “flinks.” The “winner” will be the group that stays in the middle of the water without rising to the surface or touching the bottom for the longest amount of time.

5. Give them most of the rest of the time to make their flinker, saving just about fifteen minutes for the final contest, cleanup, and thought. They can use the bottles of water to test their flinker as many times as they want. Encourage them to test often, and perhaps work on a few models at the same time (but they only get to use one per team in the end).

6. For the “contest,” have an impartial leader use the tongs to release a flinker in the center of the bottle, and them time how long it takes for the flinker to go from the center to the surface or bottom. The longest time wins!

7. Have the kids clean up and then join you in a circle. Read them Matthew 6:24 again and connect it to the lesson. How are our flinkers reflective of the scripture? (All flinkers eventually “choose” to sink or float. There’s no staying in the middle. It’s the same for us in regards to God and Mammon. Even if we don’t actively choose, we will naturally go one way or the other!)

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