Mini Smoke Ring Launcher: Explore the Properties of Air

Students made smoke ring launchers as an end-of-the-year activity on forces and motion.   They had a wonderful time counting how many rings of smoke they could get. It isn’t really smoke, but fog.  It looks like smoke, and they tend to call it that.  It was a fun activity.  

Hopefully, you have a fog machine.  They can be found online and in stores at Halloween.  If not, your students can make these and shoot little puffs of air to make small items move.  They just won’t be able to see the rings.

Supplies

Plastic Cup

3-5 inch balloon

Rubber band

Scissors

Fog Machine

Safety Goggles recommended

Directions

1.  Cut a 2cm round hole in the bottom of the plastic drinking cup.

2.  Cut the end of the balloon off.  Make sure you cut enough to be able to wrap it around the cup.

3.  Wrap the balloon over the top of the cup.  It has to be as tight as you can get it.  Work carefully so you don’t crack the cup.  Keep pulling it tight.

4.  Place a rubber band over the balloon on the cup.  This just helps to hold it better.

5.  Follow the directions for your fog machine.  REMEMBER, the end of fog machines gets hot.  Use caution and have adult supervision. 

6.  Once the fog machine is set up, hit the button to produce fog.  Place the hole in the cup close to the opening where the fog comes out.  You want to be able to catch the fog in the cup, but not melt your cup.  (I have done that.)  Let the fog go in for a couple of seconds.

7.  Take your mini smoke ring launcher and hold it up away from you.  Carefully tap the back with one or two fingers.  You should see the fog come out.  Hopefully, it is coming out in rings.  It doesn’t always do it each time, but you should be seeing some.  Count how many rings you get until you need to refill with fog.

8.  If it does not work, tighten the balloon.

Explanation

The air coming out of the cup is a vortex of air.  A vortex is a whirling mass of water or air that sucks everything near it towards the center.  A tornado is a vortex of air.  The air in the center travels faster than the outside air.  The slower-moving air on the outside has a higher pressure than the faster-moving air.  This higher-pressure air holds the smoke ring together. 

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