Vortex Cannon Build

Inspired by BrainCandyLive I decided to make my own garbage can vortex cannon. First, I needed some ideas on how to go about construction. I checked out this Instructables and Steve Spangler's website and combined the two. The build was very easy and including shopping cost under $30 and only a few hours of time.

The materials I used were a golf ball, 24" bungee cord, duct tape, heavy duty garbage bag, and a big garbage can. I chose black duct tape just so it looked better on the darker garbage can. You also need a box cutter knife and some sand paper (if you want).

I cut around the pre-made circle with the box cutter to make a big circular opening. The downside of using this particular garbage can is I didn't have much control over the size of the circle.

I found the inside of the circle to be a bit rough for my tastes so I sanded it down. I also sanded any rough spots along the top of the can to prevent them from possibly ripping the bag I was going to put over it.

You can make your vortex cannon with just a flat sheet of plastic. I decided I wanted a knob and bungee to be able to pull back and let go. Which is better I don't know, but I worried that after repeated use the plain sheet might get too loose to use. Here, after cutting the bag to a flat sheet I laid it over the top of the can and put a golf ball in the middle.

I twisted the bag around the ball and tied it with some nylon string. I made sure there was enough overlap around the can to tape down. I also at this point cut off excess bag. 

I put down four initial pieces of tape to hold the bag in place where I wanted it. I cut slits where the handles were since I would be using these to hold the cannon.

Next, I ran duct tape around the can, taping down the bag. I folded over the bag in some places and tried to get as flat a surface as I could. The can and duct tape loved attracting dust and grime in my garage and was a pain.

Finally, I ran the bungee from one side to the other while looping it around the golf ball.

That's it! Done!

I like S. Spangler's version of using a shower curtain. I believe it would have better elasticity; however, the garbage bag was available and inexpensive ($4 for 5 bags). I am also not sure I would use the bungee if I had the shower curtain due to the added elasticity. Perhaps I will make another just to experiment. The bungee pops off the golf ball more than I'd like. I'll figure out some way to attach the bungee better.

Best part of the build was the short build time. Two days after seeing one on stage my students could see one in school.

Putting on a Show

I never thought I'd have a career in theater or performance art. Then I became a teacher. Everyday at work I put on a show for 80+ teenagers. Some days the show is not very enthralling, but other days I try to put in place an experience I could sell tickets to. I'm serious. In the past few years I've gotten very serious about putting forth an experience for my students similar to experiences students might experience in theater, YouTube, or television.

My wife and I had a date night where we got to see BrainCandyLive! starring Adam Savage (of Mythbusters fame) and Michael Stevens (of VSauce fame). What a great show and what great ideas for teaching science! The showmanship of Adam's creations and Michael's depth of science knowledge led the entire audience into an understanding of air and air pressure.

One of the best parts of teaching a physical science class are the numerous demonstrations you can share with kids to elucidate often challenging concepts. As Michael said in BrainCandyLive, "You can't see air. How do we know it's there?"

Answering these types of questions in class can be both engaging and fun for students. Why would you show a YouTube video of these phenomena when you can DO them in your room in front of students! I started doing this to engage otherwise apathetic students. I realized that it was also really fun for both me and my students.

My love for this type of lesson started early in my career: before technology took over classrooms and textbooks were still modus operandi. Our school had a partnership with Capital Repertory Theatre and I teamed up with one of their employees.  For over a decade now, around Halloween, we have done a lesson on special effects, dry ice, and fog machines. This works perfectly into the unit on matter we are covering in class at that moment. Based on the success of that lesson I began working on others including:

• Air Pressure (using a vacuum pump and chamber)
• Liquid Nitrogen
• Chemical Reactions

I also do innumerable smaller demonstrations to cause cognitive dissonance and/or engage students a the beginning of a lesson/unit. Anything to get them talking science and asking questions. The ones I listed involve a full period and often involve students making predictions, asking questions, and writing responses. There is lots of fun to be had but we also need to work on critical thinking and writing. I also want to make sure they actually learned something.

Photo From Halloween 2016

Thanks to YouTube, there are a plethora of videos showing various performers (teachers) doing demonstrations on almost any topic. Showmanship didn't come naturally to me. I had to work hard at it. I have watched everyone from Bill Nye and Steve Spangler to MIT's Walter Lewin. From each video I can glean not only how the demonstration is best done but also how the content is best explained an presented. I also steal jokes and humor. Here are a few of my favorite Channels for getting ideas:

Sick Science
Crazy Russian Hacker
Tested
Jefferson Lab

I start with a blank piece of paper and write out ideas as I journey through YouTube. I later write a more formal script for how things will run in class. Everything is noted from whether the lights will be on or off to what music will be playing. My students can smell an unprepared lesson from a mile away and know when you're off your game. Preparation is key!

Most importantly for these demonstrations, I consider safety; the safety of myself, the students, and property. Even seemingly inconsequential things need to be considered. How will students be seated? How close will they be to the demo? In what parts of the lesson can I have student involvement? Where should materials be positioned? How will cords run along the floor? How should the materials be handled? What safety information needs to be shared with students?

I know great teachers that don't use "edutainment" in class. They don't feel the need to provide a show and entertain students. That is fine. This is how I enjoy teaching. I feel this is the best way to teach my students for these particular topics. I love providing wonder and hopefully spark some interest in science that will go beyond the 45 minutes of class time. I know it does because I hear them talking about it in the halls and at lunch. Students stop in to see me years later to reminisce about a particular demo or day in class. That doesn't happen with worksheets, packets, or even most cookbook labs.

Find a simple demo and work on your showmanship. Have some fun!

Dropping the Ball

Getting out of the confining four walls of your classroom is an easy way to add excitement and engagement to a lesson. The material you're trying to sell your students becomes more alive as they travel and experience the lesson. If nothing else, your class is neither boring nor entirely predictable.

For my gravity unit I take students on a trip to the stairwell just around the corner from my 3rd floor room. The idea of small "field trips" comes from Dave Burgess' book Teach Like a Pirate. Field trips are a great hook! Even though it is only 10 meters from the science room, we are still outside the room. Instant engagement!

From the stairwell I drop a baseball and we time how long it takes to hit the ground. I have one student at the bottom as my ball retriever, 3 to 4 student timers, and a data collector. The other students watch. Students get a kick out of having a teacher do something that is normally forbidden. The whole process going to the stair well and collecting data takes only about 10 minutes. I repeat the data collection at most 3 times to get decent data. No need for it to be perfect and one class period it only took one go.

Once we return to class we calculate how fast the ball is going when it hits the ground. I have them work through the math in both miles-per-hour and m/s. The field trip does not eliminate all the complaining about doing math (in science even!) but some students are excited to try and work it out and see what the results are.

Do students need to be able to do this on a test? Of course not! Do they need to understand acceleration due to gravity and how math and experimentation can be used to solve problems? Yes, and that is the goal of this activity; give some excitement to class and foster deeper understanding.