Introduction: Float Racers

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Ready. Set. Float!

As the racers take off for the top, you'll find this science-in-a-tube to be a not so dense lesson in buoyancy. Googly eyed, bubbled, and plunged, the racers battle each other in a column but with all sorts of different variables. I love this experiment in buoyancy and solids, liquid, and gasses because all students can make their own racers, and add a little lightning to their liquid lesson.

  • What: Float Racers!
  • When: 3....2....1...Now!
  • Concepts: buoyancy, states of matter, pressure
  • TIme: ~ 10 minutes to make, more to modify
  • Cost: ~$5 for tube, $0.25 for racers
  • Materials:
    • Plastic syringes (10mL work great available from pharmacies or online)
    • Large clear plastic tube with caps
    • Googly eyes (and other decorations)
    • Water
  • Tools:
    • Scissors
    • Hot glue gun / hot glue

Float on!

Step 1: Ready Your Racers

Get set!

Start with one of the plastic syringes (with no metal tip) and simply trim off the flanges so that they are more streamline and won't bump shoulders.

Hot glue some eyes or other features on to give them any kind of personality you want. They're ready to race!

Step 2: All in the Tube!

The countdown begins.

Cap one end of your tube and fill it almost to the top with water. Pull the plungers of your syringes to give them a pocket of air. This will allow them to float to the surface. The volume you choose is up to, and great to vary and experiment with. The syringe opening is narrow enough that water won't sneak in to the air pocket, which is pretty nifty.

Fill the tube the rest of the way and cap it with the racers in. 3...2....1...

Step 3: Go Time!

Go go go!

Start your racers off in an upright tube, and then flip it over to watch them go. Who won? Flip it again? Is it the same winner each time? What's happening?

They just never seem to tire, do they?

Step 4: Make and Modify Racers

The interesting bit comes in adjusting your racers. Mod time!

What happens when you add different amounts of weight to them? What about pull the plunger so that more air is trapped at the beginning? What about different shapes and vessels? What if you fill the syringe with oil instead?

Hope you enjoy and modify this experiment with solids, liquids, and gasses as well as buoyancy and pressure. Le me know how you modify it in the comments below!

Float on, keep racing, and as always, keep exploring. :)