Dot Physics

What the heck is this? (4)

Here is the next item.


There is a threaded plug on the top. I took it off so you could see inside. The whole thing is pretty heavy.

Good luck, and let’s be careful out there.


  1. #1 chester copperpot
    September 10, 2010

    Container for radioactive material

  2. #2 Ewan
    September 10, 2010

    Bomb calorimeter container?

  3. #3 Fran
    September 10, 2010

    It looks like a bomb.
    It looks like one of those bombs that you fill with water and put in the freezer, then take out later when the water has turned to ice…only to discover that the metal container has actually broken open!
    Is that what it is?

  4. #4 KeithB
    September 10, 2010

    The way they test the “proof” of alcohol?

  5. #5 Woods
    September 10, 2010

    This is a weight that you hang from a chain. You use the threaded part to attach the chain/cable to the weight, then you can feel free to hold it up to your head and let go, only to amaze everyone when it doesn’t *quite* come back and smack you.

  6. #6 Karst
    September 10, 2010

    Is that lead inside? Did someone use this for melting lead, which could then be poured out?

  7. #7 Rhett Allain
    September 10, 2010


    I am not sure it is lead – it looks like lead, that was really just a guess.

  8. #8 Tom
    September 10, 2010

    A counterweight.

  9. #9 kmorgan
    September 10, 2010

    a crucible for lead or some other heavy metal

  10. It looks like one of those bombs that you fill with water and put in the freezer, then take out later when the water has turned to ice…only to discover that the metal container has actually broken open!

    It does look like the thing I saw being so broken in a Time-Life book long ago, but I doubt that was its purpose. The filling-with-lead-to-make-a-weight theory seem reasonable.

  11. #11 Tom
    September 10, 2010

    It is indeed an “ice bomb.” You fill with water and place in an acetone-ice slurry. Throw pile of soft, heavy material over device and slurry. Make sure you have an explosion shield around the demo — you have only seconds after tossing into slurry. Breaks quickly and with force. I have seen this device in use.

  12. #12 Karl
    September 10, 2010


    Storage flask/bottle for mercury?
    Used to also come in 2-3 liter steel cylinders.
    Tried to pick one up once……threw my back out.


  13. #13 CCPhysicist
    September 11, 2010

    The hex drive on the screw cap suggests “secure” storage, so I was also going to guess mercury until I saw lead inside. I’d guess it might be a shipping container with a lead seal to contain the mercury, so the mercury wouldn’t lead out thorough the threads of the opening. Never used?!!

    (I should take off at least one ! because our lab storage area has entire complete sets of equipment that had never been used until I started using one for demos. Someone bought them with end-of-year money, never got around to changing the lab, retired, and no one even knows when or why they were bought.)

    If it is a kg of Hg, don’t tell the hazmat people on campus …

    Highly unlikely that it is a never-used cast iron crucible. You put iron in a crucible.

  14. #14 Cleon Teunissen
    September 11, 2010

    I wonder about the crudeness of the manufacturing; the thickness of the neck is very uneven.
    This thing is heavy duty, but low spec. Yeah, weird.

    And why so round? Is the bottom end completely round, or is there a small flat area unerneath? Clearly this is not intended as some bottle-like container, that can be shelved.

    Does lead dissolve in Mercury? I would expect a container with mercury to be capped with something like bitumen, not lead.

  15. #15 Cleon Teunissen
    September 11, 2010

    OK, hypothesis.

    The thing was manufactured as an ice bomb. Then someone figured: “Hey, let’s see what happens if instead of water I pour in some molten metal (lead?). What will happen when that solidifies?”

  16. #16 Afrânio
    September 12, 2010

    Very interesting.

    Take a look at my post, originally in Portuguese, which how I would like to give a first physics lesson and criticized the Brazilian educational system. I’m curious to read the opinion of someone from outside the country. Leave a comment!

  17. #17 scidog
    September 12, 2010

    i’m waiting for a search of the label..CPNCO to come up.
    dept of math in Russia?,but my old dial up has not come up with the full page yet..the diamond symbol on the side with maybe a S or a snake? a clue.i’ll just jump in and say it’s a radioactive sample that may have been sealed in lead in what ever steel bottle was at hand at the dept of math? Russia.

  18. #18 Loki
    September 12, 2010

    Counterweight for a centerfuge?

  19. #19 anon
    September 12, 2010

    The label says “Cenco”, a physics equipment company that probably made half the stuff in your high school lab.

    I believe Cleon @ 15 has figured it out.

  20. #20 air max TN
    September 13, 2010

    Pois bem, o FreeLance Switch foi criado com o intuito de combater a falta de trabalho para pessoas Freelancers, outros tantos uniram-se a criaram um espaço do género de “Classficados”, neste site podes publicar um anúncio a promover-te, mas isto não é só uma questão de te anunciares pois o site tem uma serie de secções bem interessantes, tens a secção do blog que tem artigos que te podem ajudar quanto a seres um Freelancer, também tens um Forum onde podes partilhar, publicar etc.

  21. #21 j a higginbotham
    September 14, 2010

    I like the mercury storage flask idea.

    Some older (1909 – 1914) Cenco are online at the Smithsonian:

  22. #22 Brian Gaulke
    September 16, 2010

    It’s a flask form ice bomb from Cenco Physics:

  23. #23 Cleon Teunissen
    September 16, 2010

    So the real question was: “What the heck is that lead doing in there?”

    We assumed you would present items that you had identified. As it happens, the item was an ice bomb that had suffered abuse.

    The mind boggles; why would anyone go through the considerable effort of preparing molten lead, just to pour it in an ice bomb?
    Surely, anyone with that kind of access to the equipment is a physicist?

    This is gonna haunt me forever.

  24. #24 CCPhysicist
    September 16, 2010

    All of the older CENCO cast iron stuff is pretty crudely made. We have some brackets for clamping a rod to a table and the holes are rarely centered.

    I have no idea why CENCO has that little diamond shaped icon, but they do.

  25. #25 anon
    September 16, 2010

    Besides, this particular Cenco item was designed for one-time use, so there was little point in finishing it carefully.

  26. #26 Charlie
    September 28, 2010

    A bong, obviously.

  27. #27 Jim
    November 9, 2010

    Perhaps it was used in tandem with a (now discarded) mate that was filled with liquid water and frozen.

    The liquid lead solidified and did not break the flask. The liquid water (when cooled) froze and did break the flask. Different behavior for the same general physical process.

  28. #28 John Becker
    November 10, 2010

    One of the weights for a “Center of Mass” demonstration. An older one, looks like… 70s or earlier? From back in the days when the presence of lead didn’t require the building to be evacuated.

  29. #29 Pat
    November 27, 2011

    It is a container for water. You fill it up and stick it in the freezer. The water expands and burst the container. To summarize, it’s a demo that dramatically shows the expansion forces generated when water freezes.

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