VAN de GRAAF Generator!!!!!

[Rowyrow]

Hi all WE JUST GOT A VAN DE GRAAF GENERATOR!!!!!!! EEeeeeeeeeeeeeeeeee sooooo excited !!! BUt I have no idea how to use it safely! The instructions that cam with it are a little vauge. My biggest concern is the discharge ball and the earthing cable. I haven't switched it on yet but it's killing me not to untill I know what Im doing!!!!! Any help?

[Narelle01]

Congrats!!!

but like you, i would have no idea either!!! HAHAHA!

But enjoy when you get it running!

[Rowyrow]

In my excitment I didn't see the big heading in the manual that said RUN THE MACHINE FUN IS GOOOOOOOooooo

[laurena grieger]

We also have one at our school. I asked our physics teacher to show me first, and to write down some little experiments to be used in the classroom. I wouldn't go having a go by yourself, especially if it is your first time. We have a rubber mat that we use to stand on. Have a great time, and your students will love every moment in using this. Goodluck.
Laurena
Waikerie High
SA

[nickyw]

Good luck using it in NT. We only have a window of a couple of months where we can use ours due to toooooo much humidity.

Its pretty cool though, we pile small pie plates on the top and they fly off, teacher loves to zap the kids or make their hair stand on end but you have to pick a student who has the straightest thinnest hair.

Google for the instructions there is plenty of info.

[Phoenix]

The Van de Graaffs are sooo much fun. I've got to order new belts for ours this year.
I've attached the information I found online and I love setting up these demos. The tin plates get a great reaction from the students.

As for the safety. We don't let anyone with a heart condition or pace maker use it and we place a rubber mat in front of it for people to stand on. We also get the students to remove any rings, braclets watches etc.

For the hair raising experience I've found that people with medium to long blond hair works best but it depends on the humidity. But we do also have a hair sample attached to a bannana plug that fits into the top of the generator.
In good dry weather you will get the best sparks between the discharge ball and globe.
Just make sure the earthing cable is attached to the wand/handle of the discharge ball and the generators earth point.
Hope the attachment helps.

Have Fun
Kel

[Rowyrow]

My prep room is a bit of a mess now. I taped a plastic petri dish on the top of it and put some wood shavings and some polysyrene balls in it hehe MESSSY Did I mention I'm excited?

[Lyn]

Hi Rowyrow,
Just do a search on the chemtalk site for van de graaf. There are a fair amount of tips and hints to check out. Don't be put off with the humidity. As long as you have airconditioning in your labs the van de graaf will work. I have always used a reinforced styrene box to give the students extra height so they can put their hands on the ball. The box originally had acids transported in it. Perhaps a wooden step stool with a rubber mat might be the go. All important for the kids to let go of the ball before they step onto ungrounded terra firma. Discharge the ball before the kids handle the surface and just keep the discharge ball in contact with the surface until they have their hands placed flat on the surface then remove the discharge ball and watch the hair fly.
Lyn.

[smiley]

Row,

We stand the kids on upside down science tubs, if you use those.

A Top End/Far North note: Indigenous hair almost never works, especially those kids straight off the Islands. Even my own child can't get her hair to stand up - only just a tiny bit! It's OK for those with straighter hair. But yes, floaty, fine blond hair works the best.

[vlclabbie]

Orrr I want one too! I'm obviously missing out on a lot of fun! Luckily I got to have a go when I was at high school!

[Ocker]

Hey Smiley, Is this an opening for all the blonde jokes?

[J]

Since when did you need an opening??

[Judy R]

Tip for Van de Graaff on humid days........dry dome and ball with a hand held hair dryer/blow dryer....works wonders and always discharge the dome!!!!!

[smiley]

Hey Ocker,

Why not?? Always works for me!!

[jodye]

Hi,

Our kids & teachers love the Van de Graaf but we found the Wimshurst machine works better as the humidity doesn't seem to affect it.
I love hearing the kids scream when they get zapped !! Is that wrong ???

[smiley]

Might be wrong but OH SO satisfying! Last year I lined up our juniors in lines of 3 & 4, all standing on our plastic tubs for a turn on the VDG. Finally I selected all the "notables" and lined them up. Then I accidentally zapped them a couple of times during my explanations, with John Cleese-like over-apologies each time. One of my daughter's friends caught my eye and winked, coz she knew I was doing it on purpose.

Moral of the story, don't mess with the lab tech, the scope for revenge is just SO much broader than usual.

Just remember Jodye, it's always easier to ask for forgiveness instead of permission!

[Wiesia]

We have two VDG machines. the old is working ok and the new one is dead as a table.
I have researched a bit on a net about the VDG problems, so I came to conclusion that the sphere for, some reason, does not collects any charge. I haven't spent much time with the new one, it is the other lab assistant area, but I wander what could be wrong with it?
The brushes were positioned in various positions, the belt is fine, the day is dry - but nothing. I have checked even the current between rolls, it seems to charge something, but without effect.
The VDG was working when was new, but after taking the sphere out and back something went wrong.
The sphere is big and round and whole. I have noticed that as the column over the top roller there is this round plastic well like with hole on the top of it and the inside is magnetic. The sphere has a pin on the top inside and the pin supposedly should go into the hole, I guess. Though, it is rather somebody's guess it is inside the well. It seems to, but I am kind of not sure, first for start. The second, it puzzles me is, as just around the (bottom rim) of the sphere there are few sticking out pins (inside of the sphere)? Why are they there, I am not sure. I would think that anything sharp sticking from the sphere will discharge, as the corona discharge?
Any help gladly appreciated

[Ian]

See! I knew you were all Physicists at heart!

For safety, just make sure you don't touch any shiny bits while it is turned on!.The spark can jump 30cm, so don't even get close!!! Before you touch it, turn it off, and touch the ball to the dome to discharge it. Then it will be safe.

I am not allowed to do the hair raising trick with kids any more, so have bought a wig from the $2 shop, which sits on the dome. Back when we were allowed to do it, the trick was to place the kids hand on the dome BEFORE turning it on, then turn it on, and dome and child get charged at same rate, (hence no zaps)

We use the pile of foil pie plates, beaker full of styrofoam balls (bit messy!), balloons, wig, etc

Cheers
Ian

[smiley]

Where's the fun in not getting the kids hair to stand up? Who is the fun-sucker in your state?
Boo hiss

WE still do hair-raising experiments with the kids, and sometimes even with a Van De Graff!

[sunray18]

we must be really blessed here! I have 3 of these! one really old one which gave up working.. so we got two new ones which seem to work all the time, even if its raining. we purchased the lightning leaper also but cant get it to work - maybe not enough volts going through it..
mkae sure you operate it at a distance to computers, and we make students turn off any mobile phones... no one with heart or epilepsy problems etc etc.. our new ones can still zap the 30th students who joins hands around the class...
we have used confetti in the class room - messy but lovely, pith balls, make a face on using paper - cut out eyes and stick on with sticky tape, a big mouth again stick on firmly, then have a tongue- long and red, coming out of the mouth but only stuck on the end where it comes out of mouth.. the tongue wil fly up and point.. hair works, plastic cut in strips, clown wigs also work..
oh have lots of fun!