My physics students learned about buoyancy last week with a boat-building experiment. On day 1, we designed and built boats out of clay. I gave the kids no information about buoyancy other than to say we would be studying it in this chapter. They were told to build a boat that could hold as much weight in cargo as possible. I gave them a rubric (see the link above).

On day 2, we tested our boats. Several sank right off the bat. Others held quite a bit of weight. I will refer back to these boats throughout our buoyancy studies.

Click on the photo below to see the album of photos I took:

Will it Float?

I’ve never done a lab before studying a chapter but in this case it is working really well. The kids had enough of a frame of reference to build a reasonable boat.

Put the lab before the lecture — this may just be a new model for me in physics.

Materials for the Will it Float? lab:

  • Clay: Go for the cheapest clay at the big box store. Air dry or kiln-fired are bad ideas. The first because air dry + water = big mess. And the second because it adds unnecessary time to your experiment schedule.
  • Tools: Scissors, plastic cutlery and rolling pins to work the clay.
  • Pennies: Cargo for your boats.
  • Plastic Tubs: to hold water. I used cat litter pans that held about 2 gallons each. You could also use a kiddie pool.

By the way, this experiment adapted really well to the high school level but it was “borrowed” from a first grade teacher! This thing can span all ages.