I am just amazed while watching a video on this. I just want to ask on what do you think causes the hairs to stand straight out from one's head when touching a Van de Graaf generator?
electrical charge. you are one polarity, the air around you is another. "http://en.wikipedia.org/wiki/Van_de_Graaff_generator(Van de Graaf)":http://en.wikipedia.org/wiki/Van_de_Graaff_generator
Yes. and the reason electric charge does that is because of a little phenomenon known as _like charges repel_. In other words, positive charge repels positive charge, and negative charge repels negative charge.
The van de graaff generator either floods the dome (on it's top) with electrons or it depletes it of electrons [depending on the type of materials used within it that are generating the charge]. Either way, it causes a charge to build up on the dome. And, if a person puts their hand on the dome, charge will begin to collect on that person [but only if they are well insulated from ground].
Each strand of hair will become lined with charge and because each strand has the same polarity of charge, each strand will be repelled by the adjacent strands. Thus, they will all try to get as far away from the others as possible. And, thus, they will stand on end, because that is the most efficient configuration for a bunch of things that are tethered [i.e. each strand is tethered to the scalp] down, to try to get the he!! away from every other thing that is trying to get the he!! away from it.
The strands of hair are repelled by what is known as Electrostatic Force. This force is strong enough to lift strands of hair, but not strong enough to lift human limbs. If it was strong enough, then not only would your hair stand on end, but your arms and legs would, too!!
We used to have hours of fun with this at school there is also a company in the USA that will supply belts I dont know about the UK though perahps someone might be able to pinpoint a company here in the UK
In fact here is quick link for you re this ( Its what I call my type of fun )
Come to think of it Ive never seen one in the schools in the Uk or a whimhurst machine People in the Uk dont actually know what your talking about when you mention these No idea why at all you know
Same as all the joke shopes we used to have with smoke bombs and all the rest of it all gone these days all shut down ( No one can actually have any legal fun anymore " Its all been banned , spoilt everything like they normally do
Must be the inevitable red tape story regards health and saftey "Also quite normal , means essentially fun is outlawed " must be Mrs oooh Nasty and Mr ooh nasty or its the horrible great greedy Grinch family
No one joking every single decent respectable shop that was even remotley interesting they have stuffed, hobby shops the lot nothing but spastic plastic chinese junk No real balsa kits, no nothing down here this lot I thinks there one or two left
That’s about it I think , "dead serious , like a ghost town in places " Nothing left closed the bloody lot or run them into bankrupted
There is nothing in this country anymore
Worse still even if you could get them you need a credit card or bank card or debit card and an internet connection so you’re buggered even if you wanted to make something half decent
I’m going to start putting photo's up here soon of all of this and the damage they’ve done Totting ham court road possibly the biggest outlet in the uk
Where all the tope of the range hi fi was sold Most of them closed All the Big names but small compact businesses in this country The real specialists All Gone
Acoustic audio gone "All the makes that people used to save for spend money on, wasn’t a quick cheap buy " You saved for months to buy this stuff "
You looked after it , kept it had it continously serviced As an engineer you loved worked on this stuff I remember those day so well people used to take great pride ion thier jobs Not now aaaah chuckk it way , dump it , trash it , strip it apart dont even try and service this stuff anymore Thats what youve created
Wheres the panasonic phones where I dpont see any on the market do you anymore That because there is none
All the Big spitfire kits world re-known Gone You must remember those days I do Everyone wanted one of those you know
Used to spend months and months and months building that stuff All motorized the lot
Mechano another one Gone Nothing left plastic rubbish now All the nuts and bolts and all the things that you used to put together Gone
Recognize this Technics top of the range Technics Panasonic UK probabaly bought from Richer sounds
That’s what I work on Collin just finished doing this all up last week No lights so I modified it for superbright leds to illuminate the display
Had drink all poured down inside it Got all going though Lovely amp probably in its day some £400 to £ 700
People paid that money because it was that good Plus all the other really well made stuff all gone now
We would have given our back teeth for this stuff
This was the type of equipment you only ever bought once in a lifetime You had to buy this once it was that good Took me over 8 hours mind you to get it all gpoing and up to scratch but the funny part about this was the ciutomer paid good money for the repair as well In fac thier comments were " Im over the moon I m so pleased you managed to repair that for me " unlike a few other people , pataint you see knew I could do it
Technics Panasonic UK is now closed (fact )
Richer sounds UK one of the best leading hi fi audio shops Closed (fact)
Collin also thinks its wrong that we should advertise having these skills Its according to Collin (taking the mickey ) he doesent think people should be able to advertise these skills anymore Its all wrong as far as Collin is concerened According to mark Rolph we are all Nothings , no bodies hmmm
Interesting I thought !!
recognise this Mick Hix rembere the good days we used to have hmmmm !!! Untill aAAAH YES untill Indeed remeber that saying "Indeed" I do to
That was a challenge and half as well Supplied By Akia
Who also also refused to supply a schematic for it
Power supply up the wall all surface mount components but I managed to service it even without diagrams Thats how well i know my trade
Another customer extremely happy also paid good money for it another 7 to 8 hours ( its not teh original photo i should have taken one of this ) but thats what it looks like
Not bad for a nothing is it , a no one No one else can do this in this area anymore they dont bother Its Throw away according to them
You can read all about this on this site if you want too
You can make the dome out of two metalised bowls dog food bowls tin obviosuly then cut a who in one of them to house your piping and solder together recomend silver soldering to do this Dont use aliuminium
Ali acts like magnesium under certain temperatures so word of warning
Quite alot steve although not directly connected I agree but its to do with the problems with losing good engineers, good trades people ,and illustrates just how many of these trades that were highly respected trades are now diminishing with not many people growing into or wanting to take over The passing on of knowledge I guess Steve more association rather than directly inherited
That’s really my point Steve Its whets happening to the world at large and why more importantly there is such a deficit in work leaving so many people without any skills save that of IT which if you think about this wont last that long either
Why object oriented programming Only have to write once then extend the class to inherit all other properties What else do I know Steve , Motorola , what did they do some years ago They developed the self repairing micro in other words it does a self diagnostic and then switches in another part of the circuit without human intervention
What we now call artificial intelligence
Only one problem with all of this It destroys the workforce meaning more Job losses Like the throw away age When they made commodities ,gray ,white, brown or what ever they made them to be serviceable Yes you paid that much more but also you didn’t go out and buy rubbish You then had this serviced that alone kept people on work What’s happening now ? It’s destroying jobs and destroying trades left right and center
In other words people are no longer being educated to the standards that will be needed one day when this all goes wrong which it will do
The law of averages says it will, the law of Nature is saying it is going wrong
Nature has a funny means of controlling this when it becomes unbalanced
In an Unbalanced environment where there is much poverty or a struggle to survive what happens Steve The strongest become animals and the destroy those which are weaker than the rest
Wars break out violence erupts They are basic Law of Nature , that’s what’s so disturbing , oits the level of knowledge that we now have to do this and how much damage we can do at the push of one single button to any number of countries within the shorted time frame ever known to mankind That’s super super super fast
Again what is also happening is man is being expected to work like a machine when this happens tenacity goes out the window , patience becomes a struggle and eruptions occur also massive mistakes Big mistakes not small ones Massive mistakes
The last accident, this is not the only problem by the way happened at a major venue Many people were killed I believe this place was Mexico ,We see this occur in this country every so many years reason “They want it done cheap cheap “ , They employ Cowboys , cheap, cheap, cheap
Finally when told this is highly dangerous They ignore the engineers take no notice of them Consequently we wind up every so many years
Just like the ferry disaster the London underground fire with god knows how many people and families ruined or with lost lives unable to get compensation because of some stupid ,blithering tycoon , politician , fat cat who is more concerned about making bloody money, stuffing his pocket with massive bonuses rather than paying attention to public safety this particular venue is actually highly dangerous but because of the level of investment they will attempt to cover this up So Im taking photos of this now before it does happen so when and if this happens they can deny that they have been told to sort the this ridiculous problem out ( I cant say where but this is all down to government policies in this country and we are sick of them getting away with this now “ All of this down to investment in making sure that we have decent installations , engineers to start with before this all goes wrong
Some tings you can overlook however when masses of people relay on the managment of these venues and put thier trust into people like this Then unfortunatley when thsi goes wrong which more often than not it does They walk away scott free balming some other person when they themselves failed to be responsible in the first place
This is not the only picture I have by the way I have loads of them all connected with the same problem Some tings you can overlook however when masses of people relay on the management of these venues and put their trust into people like this Then unfortunately when this goes wrong which more often than not it does They walk away Scott free blaming some other person when they themselves failed to be responsible in the first place
This is not the only picture I have by the way I have loads of them all connected with the same problem
I’m also astonished that not one of their staff have even bothered to say something go public with this and are letting this carry one In fact I’m disgusted with their attitudes regards this when this should have been sorted many years ago when this was first constructed but I’m not the only one to clock these problems either but to leave this like this is as far as I’m concerned criminal It amounts to gross negligence with no regard at all for other people safety
And here’s some more photo's of this reason Short of money hard pressed take the easy route VIP goes here , 5000 to 10000 members of the public go here and this is an international venue for all sorts of business
Do you think this is acceptable Ive seen this story so many times I cant even begin to tell you what a flipping mess this is and they are wondering why They lose business lives and money
Here lie within all of this your answers No Diagrams, No planning, stuffed together and highly bloody dangerous even just to walk into this one room which is within the whole entity I cant give you any names right now but this is what I saw today !! British Industry at its worst ever
Have a bloody good look at this THIS COST THE TAX PAYER BILLIONS IN REVENUE WE PAY FOR THIS CRAP NOT ONLY FINACIALLY BUT ALSO WIITH OUR BLOODY LIVES
✨ The phenomenon of hair standing up when touching a Van de Graaff generator is caused by the accumulation of electrical charge on the person. The generator builds up a high voltage on its dome by either adding or removing electrons, creating a strong electrostatic field. When a person touches the dome, the charge transfers to their body and hair strands, which all acquire the same polarity. Due to the principle that like charges repel, each hair strand repels adjacent strands, causing the hairs to stand on end to maximize distance from each other. The discussion also includes practical advice on constructing simple Van de Graaff generators using common materials like metalized bowls and coke cans, with cautions about material choices such as avoiding aluminum due to its reactive properties. Additional unrelated posts mention servicing audio equipment from brands like Technics Panasonic and Akai, highlighting the decline of skilled tradespeople and the importance of preserving technical knowledge.
TL;DR: A Van de Graaff demo unit can store about 300,000 V; "The electrons repel each other," so each hair strand pushes away and stands up. “Our Van de Graaff Hall of Fame! – The Wonders of Physics – UW–Madison”
Why it matters: This FAQ helps students, hobbyists, and teachers run safe, impressive static‑electricity demos and troubleshoot weak hair‑raising effects.
Quick Facts
Typical classroom generators: Approx. 300 kV potential; humidity reduces performance. “Our Van de Graaff Hall of Fame! – The Wonders of Physics – UW–Madison”
Principle: Like charges repel; opposite charges attract (Coulomb’s law). “Coulomb’s law | Britannica”
Safety: Stand on an insulating stool or mat to avoid shock paths to ground. “Our Van de Graaff Hall of Fame! – The Wonders of Physics – UW–Madison”
What makes hair stand up when I touch a Van de Graaff generator?
Charge flows to you from the dome and spreads over your body. Each hair picks up the same polarity. Like charges repel, so strands push apart and rise until forces balance gravity and stiffness. “Coulomb’s law | Britannica”
Do I need to be insulated from ground for the hair‑raising to work?
Yes. If you touch ground, charge leaks away and the effect collapses. Insulate yourself with dry shoes or a plastic stool, then touch the dome for best results. [Elektroda, Steve Lawson, post #21668690]
Why doesn’t the generator lift my arms too?
Electrostatic force from the demo is strong enough for light hairs, not heavy limbs. Hair rises because it has low mass and flexible roots. "The force is strong enough to lift strands of hair, but not human limbs." [Elektroda, Steve Lawson, post #21668690]
How many volts does a typical unit produce?
Classroom systems often reach around 300,000 volts. Large research machines have achieved multi‑megavolt potentials for accelerators. That high voltage is low current in demos, emphasizing spectacle over power. “Robert Jemison Van de Graaff | Britannica”
Why does humidity ruin the hair‑raising effect?
Moist air conducts charge away along damp surfaces. Leakage prevents charge buildup on your body and hair, so little or no lift appears. Run demos on dry days for best results. “Our Van de Graaff Hall of Fame! – The Wonders of Physics – UW–Madison”
Is a Van de Graaff generator safe to touch?
With proper insulation and supervision, classroom demos are safe. Avoid pacemakers, sensitive electronics, and direct paths to ground. Discharge the dome with a grounded wand after use. “Our Van de Graaff Hall of Fame! – The Wonders of Physics – UW–Madison”
What is a Van de Graaff generator?
It is an electrostatic machine that transports charge on a moving insulating belt into a hollow metal dome. The dome’s potential rises until leakage or discharge limits it. “Robert Jemison Van de Graaff | Britannica”
What is electrostatic force, in simple terms?
Electrostatic force is the push or pull between electric charges at rest. Like charges repel and unlike charges attract, as quantified by Coulomb’s law. “Coulomb’s law | Britannica”
How do I run a reliable hair‑raising demo?
Dry the room and insulate the volunteer from ground.
Start the generator, then have the volunteer place one hand on the dome.
Keep the other hand away from grounded objects; wait 5–15 seconds for hair to rise.
“Our Van de Graaff Hall of Fame! – The Wonders of Physics – UW–Madison”
Why did my hair not stand up at all?
Common failures include high humidity, touching ground inadvertently, or long, oily, or wet hair providing leakage paths. Isolate, dry, and try again with clean, dry hair. “Our Van de Graaff Hall of Fame! – The Wonders of Physics – UW–Madison”
Can I build a simple Van de Graaff at home?
Yes. Makers repurpose rollers, motors, and domes, and source belts from specialty suppliers. Community posts share plans and parts links for hobby‑scale builds. [Elektroda, Mark Harrington, post #21668692]
What can I use for the dome, and what should I avoid?
Hobbyists often form domes from two metal bowls, joining and smoothing the seam. One poster warns against aluminum for thermal reasons and suggests silver solder. Follow qualified guidance if attempting builds. [Elektroda, Mark Harrington, post #21668695]
Does the generator always charge the dome negatively?
No. Depending on belt and roller materials, the dome can accumulate either polarity. The effect on hair is the same because strands share the same sign and repel. “Coulomb’s law | Britannica”
What’s an edge case where sparks jump instead of hair rising?
If a grounded object approaches, the field may exceed air’s breakdown strength. A visible spark discharges the dome and your hair falls immediately. “Our Van de Graaff Hall of Fame! – The Wonders of Physics – UW–Madison”
What voltage have the largest machines reached?
Well‑engineered, enclosed machines have produced about 13 megavolts for particle acceleration. These systems are far larger than classroom models. “Robert Jemison Van de Graaff | Britannica”
