Balloon Rockets and Mentos and Diet Coke Rockets

Hi again!  I'm supposed to teach a rocket science class tomorrow and although I've taught some similar material, I haven't actually taught a rocket science class so I'm a little nervous.  Also every time I teach a science class, I'm always hoping that there are just as many girls as there are boys.  Often times, I'm a female teacher teaching to a room full of little boys and I wonder where all the girls are.  Don't get me wrong, the boys are incredibly intelligent and fun to teach, I just would like to see something closer to a 50:50 ratio of boys to girls.

Maybe the girls feel like it's just going to be a roomful of boys and they'd rather hang out with their friends doing something else. I think that's how I felt when I was younger, I didn't want to be hanging out with a bunch of boys taking extracurricular science classes because you always had to work in groups and none of the boys wanted me in their group since they were all friends with each other.  Jokes on them though... I don't know how, it just is.

Anywho, I have some interesting things I thought I would try with my first class.  I will be trying to have the kids make a sort of rocket every class.  I thought we would start of easy first, with a balloon rocket.  This is pretty simple, take a piece of string (kite string or fishing string would work well) and have it go through a straw.  Tie both sides of a string two stable pieces of furniture. Blow up a balloon and attach it to the piece of straw by tape.  Release the balloon and watch it go!  I know this sounds pretty elementary but it's eye opening when you start teaching Newton's three laws of motion.

I was also going to have the kiddos experiment with different things like; 1) does the shape of the balloon (airship vs. round) affect how fast or how far the balloon travels 2) does the length of straw affect things 3) does the type of string affect how fast or far the balloon goes (this is where we can start to talk about friction and how it comes into play with newton's first law of motion).

The next experiment I was thinking of doing was the classic diet coke and mentos experiment.  This is where you drop a bunch of mentos into a huge thing of diet coke and watch the diet coke explode.  This is all due to nucleation! Mint mentos works best since it has the rough surface creating all those nice tiny crevices.  Since mentos are more dense than the liquid they are being dropped in, they sink to the bottom, thus reacting with the CO2 all the way at the bottom of the bottle.  The CO2 gas is just looking for any escape out of that bottle and upon realizing that the mentos has all these tiny crevices it can escape into,they all race to get into the crevices, but there is not enough crevices and the CO2 gas molecules that didn't find a nice crevice become enraged and erupt out of the bottle.  Okay, not exactly, molecules don't have feelings but you get the point right?  So....I was going to have the students make their own diet coke and mentos rockets by doing the following.

1. Tape a string of mentos together and then tape a piece of string onto the already taped together mentos.

2. Tape a narrow tube around the cap of the diet coke bottle, something that is smaller than the paper towel roll (see number 3).

3. I was then going to have the kids make a rocket by using a cardboard paper towel roll. The top of the paper tower roll would be duct taped closed and then a small hole can be poked through the hole where string from the taped mentos can be fed through.  They can cut out fins for stability and also make a coned top to make their rockets more aerodynamic. The string that is attached to the mentos would also be fed through the coned top.

4. When the students are ready to try their rockets, we would go outside and avoid parked cars, windows, and people for that matter.  We would then open the cap of the diet coke. Place your rocket on the bottle, and slowly feed the mentos into diet coke bottle and let the mentos sink to the bottom of the bottle.

4. Then we stand back and see what happens!!












Well I'm excited to teach my class tomorrow, hopefully they like what I have planned and some of the rockets actually fly, it's pretty disappointing when stuff doesn't work, but alas, that's how science goes. I remember in graduate school, it was often times by accident when you discovered how to make certain things work, then if you could replicate it a bunch of times, you just pretended that you intended to make that "mistake." Anywho, I hope these experiments work for you guys! Cheers!