200KV Capacitor Uses Cake Pan and Bowl

[PhysicsGirl] posts videos that would be good to use in a classroom or homeschool environment. She recently showed a 200KV capacitor made from a cake pan, a bowl, and some other common items (see video, below).

One of the most interesting things about the project was how they charged the capacitor. A PVC pipe and some common hardware made a wand that they’d charge by rubbing a foam sleeve up and down against the dome formed by a metal bowl. We might have used a cat, but there’s probably some law against that.

To discharge, they used the end of the wand and were able to get a 10 cm spark. Based on the dielectric constant for air, they estimated that equated to a 200KV charge. They also discharged it through someone’s finger, which didn’t seem like a great idea.

We’ve talked about [PhysicsGirl’s] videos before. Granted, a lot of this won’t help the experienced hacker, but if you work with kids, they are a great way to make physics interesting and approachable. We wish she’d spent more time on the actual construction (you’ll need to slow it down to see all the details), though. If you really want a capacitor for your high voltage mad science, you might find these more practical. We’ve seen many homemade capacitors for high voltage.

21 thoughts on “200KV Capacitor Uses Cake Pan and Bowl

  1. The problem with using cats is the cat would simultaneously charge and discharge the capacitor in such a way that the capacitor is neither charged or discharged. More due to Schrodinger than cruelty.

  2. So cute women can be all Sciency and girly but the average person can only name Madame Curie,( I give the benefit of the doubt to “average” people), as a female hard scientist and can not name a second one. Same is true with Black and Hispanic scientists. Maybe they deserve more spotlight than singers and actors.

        1. It has nothing to do with here sex and the people who look down on her for not being the same colour are also female. They literally can’t get their heads around the fact that she has more qualifications than all of them put together.

          1. And this shows how wrong YOU ARE, assuming the feeling (not actions) of others towards whom is your wife in this case.

            I doubt very much that anyone, in a scientific/educated environment, will actually DO things to belittle or humiliate another person.
            If, on the other hand, the other person (the “victim”) chooses to feel inferior then it is a matter for the victim to be counsel.

            I am truly sorry for the feelings that you and your wife have.
            Based in your version of the truth, she is just one more in the team and shouldn’t expect special treatment. May be that is the problem … “I have 3 PhD s, I am better than you”… sound familiar?

            Grow up.
            The world IS NOT against either of you.

          2. I made it clear that the others were not anywhere near as educated. What do you think “white trash” means? You are an idiot and you should stop deluding yourself that you are grown-up when clearly you are both naive and suffering from comprehension problems. Your sense of maths is retarded too, below average people would only be 50% of the world.

      1. I’m not denying the existence of white trash, But could you elaborate on her treatment?

        You see, Women like to play flirtatious games then pull the victum-card when they get undesirable attention.

          1. Women wage conflict onto other women, Purely not race related. But depending on their class they can get away with it. Especially when it comes to them string up conflicts in the work field, Of which men have gotten fired for
            calling them out on it.

  3. Predating Schrodinger and defining the real reason cats can’t be used.
    https://en.wikipedia.org/wiki/Cheshire_Cat
    “he Cheshire Cat is now largely identified with the character of the same name in Lewis Carroll’s novel Alice’s Adventures in Wonderland. Alice first encounters the Cheshire Cat at the Duchess’ house in her kitchen, and later on the branches of a tree, where it appears and disappears at will, and engages Alice in amusing but sometimes perplexing conversation. The cat sometimes raises philosophical points that annoy or baffle Alice; but appears to cheer her when it appears suddenly at the Queen of Hearts’ croquet field; and when sentenced to death, baffles everyone by having made its head appear without its body, sparking a debate between the executioner and the King and Queen of Hearts about whether a disembodied head can indeed be beheaded. At one point, the cat disappears gradually until nothing is left but its grin, prompting Alice to remark that ‘she has often seen a cat without a grin but never a grin without a cat’.[5]”

    1. Straying further from the subject of the posting: my school physics text (Nat Phil O, as it was called) pointed out that the abolition of the ether as a medium for electromagnetic waves was an example of a “grin without a cat”: the wave exists without anything to be waving.

    1. Because they only exist in the world of YouTube and other virtual fantasies.
      In the real world they are VERY different …

      Stay happy as you are. The grass is NOT greener anywhere else.

  4. It’s reassuring to see that a sizeable segment of the HaD audience still thinks women are a different species. For a moment I was worried that we might be making progress toward being less of a stereotype.

    1. Nerdy girls don’t love you bro, Quit white-knighting.

      Women can begin to receive equal treatment when they receive they get the same legal, sociological, carrier-related
      representation as that of a man. Which in western civilization, female supremacy runs ramped. Look at the divorce courts, false rape ligations, and prison sentencing for identical crimes. All scenarios females are more-so pardoned for as opposed to men.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s