Giving a presentation on water blaster - i don't know where i should put this

[USSA]

I may be giving a presentation about air pressure water gun about a week and a half from now to my fellow campers. Any suggestions for things i should mention would be greatly appreciated

[isoaker]

What type of presentation? What do you plan to talk about? Are you talking about blasters or the technology behind the blasters or comparing manufacturers or something else entirely?

[USSA]

oh srry, well its a science camp so i'm probably going to talk about how water guns work (the principles and all that dandy stuff) (think howstuffworks.com) and may take a blaster apart for them. (i neglected to mention i shall be preaching to 8 year olds so no advanced physics... everything must be in layman terms)

In a nutshell i'm going to talk about the "technology behind the blasters" and may drift over to lonnie johnson

[isoaker]

Well, in that case, the "How Stuff Works" articles make a good starting point... are you allowed to demonstrate a water blaster in action?

Feel free to bring up the online soaker communities such as SSC and here!

[Veteran]

Just wondering, but why air pressure over CPS?

[USSA]

well i don't want to try and teach them the theory of cps (air pressure seems easier) and (mainly) i don't believe that i can justify that to the science counselors.

[Field Marshal Yang]

well i don't want to try and teach them the theory of cps (air pressure seems easier) and (mainly) i don't believe that i can justify that to the science counselors.

Yeah, a lot of science teachers obsess themselves over the implications and uses of air pressure, such as bottle rocket and the original Power Drencher (SS). And of course, there''s the classic example of putting a expandable object in a vacuum and watching it expand and contract. If you've got one, present it with a water balloon and watch it splatter apart.

[Big Bee]

A visually interesting demonstration would include putting an air-filled balloon into the tank. You need practice to get the size right, it needs to be big, big enough to be seen easily, not so full of air, so it is still squishy, so you can squeeze it through the refill opening to the tank. As you pump it up, the balloon gets much smaller, and as you shoot it, it gets big again. You need a single pressurized reservoir model for this, and one with transparent tanks.

[Field Marshal Yang]

My science teacher taught us about air pressure and expansion/contraction by putting some soft candy (peeps, I think) into a vacuum chamber and removing all the air from it. It started expanding rapidly and then popped. Then he put another one in and increased the pressure flattening it. At the end, he went quickly back and forth with low and high pressure, making the candy get bigger and smaller over and over. Very fun to watch and I like to see it happen to a ballon as Big Bee described.



Edited By Field Marshal Yang on 1090090839

[Veteran]

Really? We were given a demonstration similar that instead consisted of floating diet cokes in a tub of hot water, it wasn't a very good demo.

[Field Marshal Yang]

Speaking of coke demos, my teacher also did one in which he heated water in an empty coke can to boiling over a portable heater (a lot hotter than stoves). When the water was at a roaring boil, he took the can off the heater with tongs and quickly placed it opening down in a tub of ice water. the coke can was instantly crushed, as all the sudden temperature change and the lack of air in the coke can since there was boiling water in it created a full vacuum. We played with the crushed can later until the teacher told us to get back to classwork.