Marshmallow guns (#made4math 7/16)

I know you think marshmallow guns aren’t EXACTLY #made4math because it’s one of my former middle school projects – kinda like my Shrinky Dink post.

The way it IS #made4math: it’s something you can use to teach statistics and probability and use for data collection with common core. But in order to get THAT stuff, you gotta come to TMC12 or wait until it’s over – this is one of my “Favorite Things”. ☺ The way it’s NOT #made4math: it’s just a really cool CHEAP thing to give a kid (or adult, like me) to keep them entertained for a while. My son and I have marshmallow wars all the time (outside, of course). And in true ApproxNorm fashion, I totally let my students make these (including the cutting) in class to teach measurement. So it might be a cool thing for middle school or higher if you’re brave.

Marshmallow Guns (ApproxNorm Style):

1. Go to your favorite home improvement store – head for the plumbing section. Look for the PVC pipe. You want ½’ inch pipe. It’s pretty cheap – $1.68 for 10 feet at my local Lowes. How much you need is determined by your design (tons of ideas on Pinterest) and how many guns you want. I usually use 20 inches per gun, so you can get about 6 out of one piece of PVC pipe.

**If you don’t have a saw at home, you can pick up a pair of PVC pipe cutters for about $10 – $12. This is what I use – more on that later.

2. Next you need to find the joint pieces. BE CAREFUL. You want the joint pieces the PVC pieces will SLIDE into. These are usually the cheapest ones. Make sure you get ½ inch joints! If you get ¾ inch joints you’re gonna have a problem!

Thankfully, Lowes has “contractor packs” of joints so you can save a few pennies (and some searching) by buying a bag of ten. You need two 90 degree elbows and one “T” (or “tee”) piece per gun. I was doing 10 guns, so I bought 2 packs of elbows and a pack of “T”’s. (Why 10 instead of 12? Think about it… you’ll figure it out.)

You’ll also need a cap to go under the handle so the marshmallow doesn’t fly out of the bottom. The caps are the most expensive part of the gun, so the bag of 10 cost me a little over $3.

(I’d have, um, shown you a picture of the caps bin like the other two, but uh, it was on the top shelf. I couldn’t reach it. **shocker**)

3. If you want to paint it, pick up a can of spray paint in your favorite color and head towards the checkout isle. Here’s my receipt for everything I needed to make 10 guns. See if you notice where they messed up:

Yep, they only charged me for ONE cap instead of a contractor bag. So my bill should be a few bucks more, but I chose to spray paint one for @druinok. So if you do the math, my bill should’ve been about $14.97 with tax JUST for the guns which comes to about $1.50 per gun. Not bad, huh?

Side note: Not only is this a great tool for data collection, middle school students could use the cost and receipt to calculate tax, total cost, unit price, percent of increase if you buy individual instead of in a pack, etc. MAN!!! I MISS MIDDLE SCHOOL!!!

4. Find a place to work. I like to be outside when I work on stuff (even when I blog), but that’s a personal thing. You need your PVC pipe, a pencil, a ruler, and your cutting method (for me, the PVC pipe cutters):

(ok, the beverage isn’t a necessity, but… you know me. *wink*)

5. Start by marking your PVC pipe. For each gun, my design requires: one 2 inch piece, two 3-inch pieces, one 5 inch piece and one 7-inch piece. How you mark and cut is up to you. Some people like to “mark and cut” as they go. Some people like to mark everything, THEN cut. Some people like to mark and cut what they need for each gun. I like to mark all my 7 inch pieces first, then all my 5 inch pieces, etc., and cut all at one time.

If you’re doing a lot with the cutter, you’re going to get sore so don’t say I didn’t warn you.

Side notes about the PVC pipe cutters:

I’ve heard SO many people turn down this project if they didn’t have a saw or with students because of the PVC pipe cutters. “You have to have muscle to use those cutters and I and/or my kids aren’t strong enough.” That’s just crazy talk. I am NOT photogenic like @Fouss and I hate having my picture taken. But I wanted to prove to you, sloppy ponytail and all, that I made these myself.

If I can cut PVC with my spaghetti arms:

then SO CAN YOU, so zip it.

If you’re considering this as a class activity, you need to make a few on your own FIRST to see how the PVC cutters work. The ones I use don’t cut much at a time and would be good for students. I would “train” one person in each group to be the cutter and make sure they could PROVE their abilities before allowing them to cut. This might be too scary for you and that’s fine. You could get some moms/dads to volunteer to come to class one day and assist with the cutting.

6. The entire process of marking and cutting the pipe for ten pieces took me a total of 30 minutes, but that included me talking to neighbors, yelling at the kid to stay off the roof, etc. Once you’re finished, the assembly is as followed:

See?? Easy breezy. And you can change it up to see if/how the rearrangement of the pipe gives you more/less distance.

7. Obviously you have to use the mini-marshmallows for the gun.

To launch one, there are several different ways but I usually put the marshmallow in the 2 inch piece (that’s the mouthpiece) and launch it IN the gun. Some people launch the marshmallow from their mouth/tongue, but that’s just a glorified spitball (EW). I also wouldn’t put my mouth ON the mouthpiece if I were you.

Hope you like it!

P.S. If you’re coming to TMC12, I’m giving away a few of them so be ready for a war!!
(You didn’t REALLY think I’d do a presentation on marshmallow guns and not try to start some trouble, did you???)