My First Day of School and That Pesky Exploding Can

Okay, so my first day of school was over a week ago. If this is how my year is going to go, I should just start hibernating now!

There has been a lot of discussion about this on every listserve you can find about what to do on the first day of school. Everyone is pretty much in agreement that reading through a syllabus is a great way to immediately cause disinterest in your class. The Marshmallow Challenge seems to be a popular choice with the physics crowd, and to be honest, I really want to try that in my classes some day. I teach Chemistry, so I kind of want to keep in with a chemistry theme and, of course, the question on every teenager's lips seems to be "when are we going to blow something up". The Modeling has an Exploding Can Demo set as the first activity to do with the kids and there has been some discussion about that activity as well. Some teachers cannot do this because they do not have access to natural gas. Some like to go over their class rules on the first day (why, why, why??). And some don't like the activity because students have a hard time explaining what is happening.

I love this demo and find that the first day of school is the perfect time to do it. My principal even came in to do a short evaluation on the first day this year (seriously???) and was pretty surprised that we were already in the lab causing a ruckus.

It's a simple demo that catches kids off guard, because about the time everyone stops paying attention and chatting about their summer, the thing explodes. I had one kid this year who actually dove under the lab table to take cover. He may never live that one down.

To specifically address those teacher who don't want to use the demo because kids can't explain it, you are absolutely correct. That is the whole idea. It's OKAY not to be able to explain something. If those kids could perfectly explain every action of every particle inside that can right now, then for goodness sake, send them to the counselor to get into a more advanced class. The whole point of a chemistry class, after all, is to learn how matter interacts with other matter.

This demonstration actually serves several purposes for me. First, most kids have reformatted over the summer and need to get some of those brain gears moving. Second, we come back to this demo several times throughout the year. After talking about reactions, for example, we go back to page 1 in our lab book and re-describe what we think those particles were doing inside the can. And finally, after the demo, the groups draw their particle representations of what they think happened and the next day we whiteboard those ideas. This is where I set up my norms for our whiteboarding sessions.

I try to pick kids that I have worked with in the past or who know a little bit about me and have them be the presenter for their group.

And then I grab my bag of chips. A snack size bag with just a few chips is perfect for this. While the group is presenting, I munch on chips. Doritos work well because they are really loud and kind of messy. I create a pretty decent distraction by crumpling up the bag and stuffing it into these mysterious little compartments in my desks. A couple swigs from my pop bottle (shake it up to get a nice loud escape of gas) and it goes flying across the room into the trash can. Usually by now, kids have noticed. I kind of look around the room, "oh, was that inappropriate?" My apologies. I then have the group make a note on the board.

The next group is a little nervous now, so I leave them alone.

Third time's a charm, so I get out my phone. I have it set to make the beeping sounds when you type so kids know what I'm doing. Of course I "try" to hide it like my students do, but pretty soon, they start to notice. "Oh, was that inappropriate as well?" Please make a note.

Now the last one is kind of tricky. I have to have someone presenting that knows me pretty well or I let them know ahead of time what I'm going to do. I don't want anyone in tears on the first day. After they present, I pretty much argue that my answer is the correct one and their group is just plain wrong. I usually have a hard time keeping a straight face for this one.

So now we have three things on the board that we as a group have more or less decided are inappropriate for the setting. They then get to suggest any other behaviors that might best be left at the door. We talk about how important the whiteboard sessions are when it comes to getting information. We talk about the difference between hearing and listening. We talk about respect. We talk about general polite behavior.

These two days are a pretty good introduction to the class as well as the general setup of the modeling classroom. The kids get to experience what the rest of the year is like and possibly more importantly, do NOT get the answers on the first day. This can be uncomfortable for a lot of kids and some do not handle it well.* I have actually had kids ask me for a textbook so they can look up the right answer. Good luck with that.

Learning in this room isn't about getting the right answer RIGHT NOW. It is about having to discover the right answer in another place and time and connecting it back to what you did on the first day. If I can get you to do that, then I have done my job and can sleep well at night.

Have a great year!


*From some of the discussion, some of the teachers do not handle it well. Get over it. Nobody knows it all. And besides, if all you do is tell kids the correct answer, you are taking all the fun out of science class!