let me entertain you

In 1913 the Russian author Yakov Perelman wrote a charming book called Physics for Entertainment. It’s of interest to more people than just  science students as I’m sure nursemyra is not the only person who wants to know how to jump safely from a moving car or how to make a set of scales say I weigh less than I do.


Play game by clicking here

How to jump from a moving car: Most people think you should jump forward in the direction the car is travelling to comform with the law of inertia. But inertia is of secondary importance

When you jump your body has the same velocity as the car. By jumping forwards we increase that velocity. Our speed then is greater than when jumping backwards. But remember if you are travelling with luggage you should throw that off backwards first

How to weigh yourself: you will get your correct weight only if you stand on the scales without moving. If you bend down, the scales show less*** because the muscles used pull up the lower half of your body thus diminishing the pressure you exert on the scales. 


the book is full of experiments you can do as well. Here’s one that shows you why you can’t rise up from a sitting position in a chair


and it’s got nothing to do with being tied down……

*** hands up everyone who’s going to bend over when weighing themselves from now on

Published in: on March 17, 2009 at 6:52 am  Comments (33)  

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33 CommentsLeave a comment

  1. Really, where do you find all these goodies? I am impressed that you can hold down a job and still find the time to dig this stuff up. Kudos

    well if I pursued a social life my blog might suffer 🙂

  2. OK, I’ve weighed myself. The advantage gained by bending over was cancelled out by breaking wind which is lighter than air and I actually weighed more in the end …… so to speak ….

  3. Great book! I just blew an hour with it that I should have spent working.

    Now I have to get his other books . . .

  4. Yakov Perelman’s first claim to fame was eating 11 urinal cakes after a 2 day Guinness and Vodka binge in the back streets of Auld Reekie.

    No wait! … thats wrang. It was wee Billy McGregor on our lads weekend in Dublin.

    Ah’m getting all confoozed again. Must be the drink.

  5. hey jimmy – I’ve just popped over to your place for a guinness and you’re CLOSED… WTF?

  6. I hope we aren’t expected to try the throwing ourselves from a car experiment at home?

  7. No no no of course not misteranchovy. but you are expected to try the Hoff game 🙂

  8. Should I be in need of escape from a car than I will use this advice immediately. That’s a very bad but addictive game you’ve linked to nurse.

  9. I prefer to throw others from the car, then inertia becomes much less than a secondary concern to me.

    you’re evil unclekeith

  10. Forwards? Backwards? If you don’t jump sideways you’re under the wheels. With no dollbaby.

  11. I live quite near Leith, so I try to avoid bending over at all times.

    How about a game where you get to punch The Hoff repeatedly in the mush?

  12. PS. I found it strangely entertaining,as I do anything that involves giggling attractive girlies.


    I mean *giggle*

  13. I feel kind of bad having just ran over Pam Anderson several times. But, since it was with The Hoff, it’s all good.

  14. Thanks for the tip about jumping out of a moving car. I don’t think I’ll be using this anytime soon as it has always been my experience that exiting a car is much easier once it has come to a complete stop. However, if David Hasselhoff is in the same car as me, this might come in handy.

    Thomas 🙂

  15. nurse -thank you for these handy escape artists tips. I will put these to use the next time I rob a bank and am tied to a chair for interrogation then involved in a high speed chase with a suitcase full of money.

    😉 fun read.

  16. A mate of mine made saffron buns with the Hoff in Hawaii. I’m still impressed when he tells us this.

    Is that code for something beachbum?

  17. I’ve had days where I’ve felt like jumping from my moving car, but I think it might freak out the other drivers if I let it carry on on its own..also I’m usually too far from home to walk back.

  18. Weighing youself is cruel. I avoid this cruelness!

  19. why bother Dolce? we already know you fit comfortably into the palm of Kyknoord’s hand xx

  20. I know of no position from which I cannot rise.

  21. Props for anyone named “Yakov!”

  22. Throw the scales out of the car.

  23. Well.
    I know what I’m going to be doing this weekend

  24. >>If you bend down, the scales show less*** because the muscles used pull up the lower half of your body thus diminishing the pressure you exert on the scales.

    Are you attempting to bait me, Nurse Myra?

    The above statement is completely and unequivocally incorrect. Providing you don’t touch anything that is not on the scales (ie, don’t hang on to a towel rack or a chair), it does not matter a whit whether you bend down, stand up, sit, squat or balance on one leg. The scale will always show you weighing the same. The explanation offered (that your muscles pull you up) is the equivalent of saying that you can lift yourself off the ground by tugging on your bootstraps. Your muscles (any muscles) only come into play if they can act on something outside the system of you and the scales (for example, if you hold onto a towel rail while weighing yourself, you can transfer some of your weight – via your arm muscles – to the towel rail).

    It is possible that you may see some fluctuations in the scale when you move to bend down, but that has to do with transference of potential energy into kinetic energy, and after a brief moment the weight will settle to the same number as it was while you were standing up.

    But don’t take my word for it! This is science, after all – unlike religion, you don’t have to take it on faith: you can try it for yourself!

    what do you mean “don’t hang on to a towel rack or a chair”? how else does one weigh oneself? surely you don’t just stand there without holding on to something? oh my god… does that mean I’m really not 51 kilos any more?

  25. Jump into my car…the video

    For once I am delighted my speakers are not working

  26. thank you, analglyph, for covering the science… that allowed me, in a highly inebriated state, to just drive the hoff-mobile, avoiding chubby blokes and nailing hotties. i think i achieved 40 cm of penile extension – which is even more impressive when you consider the fact that i’m a chick… [thud… collapse]

  27. The hoff was in the John Waters movie I watched last night. Only for a second thank god.

  28. oooh which JW movie was that?

  29. >> does that mean I’m really not 51 kilos any more?

    Very possibly.

  30. At least by bending double I can actually read the scales for a change. Lol!

  31. I didn’t have much luck picking up the babes, I probably would have done better picking up the bald guys. Excess testosterone makes you lose your hair, they say.

  32. I like guys with shaved heads

  33. A Dirty Shame, it was quite good.

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