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  • Which is denser, custard or water?
  • miketually
    Free Member

    Which is denser, custard or water?

    Admiralable
    Free Member

    Depends on the mix of custard but I’d say Custard. Jon Tickle ran across some in Brainiac

    Hohum
    Free Member

    Can’t you shake custard violently and it becomes almost solid? I remember seeing that on television once.

    nickc
    Full Member

    Isn’t it a Non Newtonian liquid? As per Admirable, you can run across it, but stand still you sink.

    RealMan
    Free Member

    Custard is a non Newtonian liquid (or something like that), so the more force you apply to it you more resistance it becomes. Therefore if you jump into a pool of custard you will not sink, but if you step onto it slowly you will. As for densities, I’m not sure.

    crikey
    Free Member

    Is density not a measure of how many little molecule thingys you can get into a given space? Water molecules might be smaller than custard molecules (and custard will contain water molecules and sugar molecules and custard molecules) so water will be denser.

    miketually
    Free Member

    It’s definitely more viscous, but that’s not the same as density.

    RealMan
    Free Member

    Not sure on the logic there crikey. If you really wanted to find out, measure out 500ml of custard and 500ml of water, then weigh them. The heavier one will be denser.

    Random bit coming back from physics a level – I think water has a density of 1000kgm^-3

    Anyone?

    Cougar
    Full Member

    A quick Google would suggest that custard has a density of 1.07g/cm^3. Water is 1g/cm^3. So, custard is nominally denser than water, and tastes better in trifle.

    wwaswas
    Full Member

    is the custard shark infested?

    PeteG55
    Free Member

    Wasn’t that down to it being a ‘newtonian’ fluid or something rather than its actual density? I’m trying to remember, because all I saw was that brainiac too.

    Graham_Clark
    Full Member

    Custard (and corn flour, etc.) are all Shear Thickening Fluids… Stir them, hit then, etc and they become thicker to the point, sometimes of being almost solid… Bit like the fancy stuff in those new style pads (D30, etc.)

    miketually
    Free Member

    Sea water is ~1.2gcm^-3.

    I could float custard on sea water and then fresh water on top!

    Bez
    Full Member

    Is density not a measure of how many little molecule thingys you can get into a given space?

    No, it’s not. HTH HAND.

    nickc
    Full Member

    Bit like the fancy stuff in those new style pads (D30, etc.)

    knee pads made of custard, shocker!!

    SurroundedByZulus
    Free Member

    Get yourself a kilo of water and a kilo of custard and see which fits in the smaller space and there’s your answer.

    wwaswas
    Full Member

    I’ll warrant a kilo of water will be near as dammit 1 litre.

    rootes1
    Full Member

    tomato ketchup is the opposite of custard…

    it is thixotropic… that is its viscosity is inversely proportionate to its rate of shear…

    that is why you have to tap the bottle to get it out…

    miketually
    Free Member

    knee pads made of custard, shocker!!

    They make bulletproof vests out of custard.

    Cougar
    Full Member

    Ketchup isn’t thixotropic. With thixotropic liquids, viscosity changes over time. http://en.wikipedia.org/wiki/Shear_thinning

    Semen is, though. That probably explains why an amount of bottle-shaking is required there too.

    Bez
    Full Member

    I’ll warrant a kilo of water will be near as dammit 1 litre.

    If the figures quoted above are correct, though, then unfortunately so will 1kg of custard.

    tron
    Free Member

    There’s a journal article where they mention the density of custard if you Google – it’s over 1g/cm^3, so custard’s denser than water.

    It’s also thicker.

    t_i_m
    Free Member

    more force you apply to it you more resistance it becomes

    just an inability to change shape/move quickly, this is more visible the harder/faster that you try to move it. Same with Blu-tack: can slowly shape it but hit it with a hammer and it will shatter.

    alex222
    Free Member

    Blu-tack: can slowly shape it but hit it with a hammer and it will shatter.

    I smell BS

    jonb
    Free Member

    The problem with custard is that it is viscous so perhaps you could make it thick enough that it would be able to trap air if you mixed it (a bit like angel delight) and then reduce the density.

    RealMan
    Free Member

    Blu-tack: can slowly shape it but hit it with a hammer and it will shatter.

    I have blu tack, and a hammer downstairs. I’ll let you know.

    bassspine
    Free Member

    Silly putty too, you can slowly shape it but hit it with a hammer and it will shatter.

    TandemJeremy
    Free Member

    silly putty certainly shatters if you hit it with a hammer.

    The only way to tell about the density is to have a bath in it. Eureka!

    RealMan
    Free Member

    I smell BS

    You smell correct. Blu tack does not shatter when hit with a hammer.

    kevonakona
    Free Member

    Oh and custard is not non-newtonian. The Brianiac used a cornflour mix (In Richard Hammond’s pool). It has to do with particle to liquid ratios. It’s why sand near the water is hard but when the water runs over it you sink.

    If you doubt the above about custard get some and stir it quickly, now get some cornflour slowly mix in a little water until you have no lumps now stir it quickly.

    alex222
    Free Member

    It was among the many things I hit with a hammer when I was a child.

    tron
    Free Member

    If you doubt the above about custard get some and stir it quickly, now get some cornflour slowly mix in a little water until you have no lumps now stir it quickly.

    Custard powder is just cornflour and colouring IIRC.

    kevonakona
    Free Member

    Ingredients

    570ml/1 pint milk
    55ml/2fl oz single cream
    1 vanilla pod or ½ tsp vanilla extract
    4 eggs, yolks only
    30g/1oz caster sugar
    2 level tsp cornflour

    As opposed to the cornflour thing which is just erm……..cornflour. As above it’s a solid to liquid ratio. custard has much less cornflour and so is not non-newtonian.
    you’d need loads more cornflour.

    Bez
    Full Member

    Custard powder is just cornflour and colouring IIRC.

    And which of those two ingredients tastes of vanilla then? 🙂

    CHB
    Full Member

    As said above, custard will be denser.
    Also don’t confuse density with viscosity.

    Its because custard is a solution and as crikey so beautifully put it, with solutions you can “get more molecule thingys in a given space”. Just like sea water, which is heavier due to disolved salt.
    Start getting air trapped in the custard though and all bets are off!

    rootes1
    Full Member

    ”Ketchup isn’t thixotropic. With thixotropic liquids, viscosity changes over time. http://en.wikipedia.org/wiki/Shear_thinning”

    Will have to write to heinz to remonstrate for their misinformation!

    Cougar
    Full Member

    Heinz in “lying in their advertising” shocker. You’ll be telling me next they don’t have 57 varieties.

    theotherjonv
    Full Member

    ketchup also has a yield point. Get a bottle, turn it upside down and it won’t flow out.

    Shake vigorously (shear it) and it will get less viscous and flow out. HOWEVER; even if you stop shaking it will continue to flow once started, even once the shear is removed.

    djglover
    Free Member

    I work with Jon Tickle

    Fact

    Spongebob
    Free Member

    I’m hungry now! 😕

    *reaches for the Bird’s custard powder. MMMMM 😆

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