- And how much dry weight do you remember?
- A hundred point one yeah.
- A hundred point one okay.
What we're gonna do is put it on,
because it's a little tricky to get it on
without leaking the water.
Then you guys are gonna pump it up,
and pull the string and launch it.
Feel good about that?
- [Student] Feel good about it.
- Okay.
- [Students] Three,
Two,
One.
(rocket launching)
Wow!
(laughter)
(excited, indistinct exclamations)
Three,
Two,
One.
(rocket launching)
(laughter)
Three,
Two,
One.
(rocket launching)
Wow!
- What do you have for pressure?
80? Okay it could go off any second now.
(laughter)
(rocket launching)
- [Students] Wow!
(laughter)
-Woah, it's going to come down on us!
Maybe? No...
- (students) Is it going to ...?
- [Instructor] Nice flight.
- It was our first rocket.
It was the first one we launched.
I barely saw it though.
It was so fast.
- I don't know how far up
it went but it was cool.
- The students did a fairly complex
 mathematical, computer...
numerical model I should say
of looking at how these rockets work
millisecond by millisecond
integrating the equations
acceleration, all the basic
laws of the Ideal Gas Law,
and the Bernoulli Equation
and looked at this
in an accelerating reference frame
of the rocket accelerating.
Then they were able to predict how high
these rockets would go and
use their model as a tool
to design the optimal rocket as it were.
What size nozzle?
What should it weigh?
How much water should you put in?
With a few of these
parameters they could change
and try to come up with a rocket
that would work really well
based on their computer model
that they built from scratch.
So today was the fun part,
where we just go and get to see how
a bunch of these things work.
So that's the quick summary.
(laughter)
