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Another thread of mine about making home-made custard using a whole egg and yellow cornflour/maize flour created a single post about non-Newtonian fluids. Now you are going to need to think a little about this one and use some cooking knowledge and some of what is described below...
Being the PhD organic chemistry study that I was, and studying surface tension, I thought I would see how many of you knew which of the following food related liquids were non-Newtonian after a quick description of what makes a Newtonian and non-Newtonian fluid.
So in a non-Newtonian fluid, doubling the speed that the layers slide past each other does not double the resisting force. It may be less than double or it may be more than double. The resisting force behind how hard it is too move these layers... Or in cooking terms stir it.
So which of these food and drink related items are non-Newtonian fluids ?
Not an easy one this one and it will take a little working out, but quizzes are not meant to be easy and this for me, is not too difficult to work out whereas the cryptic crossword clues on food and drink just have me totally defeated!
Being the PhD organic chemistry study that I was, and studying surface tension, I thought I would see how many of you knew which of the following food related liquids were non-Newtonian after a quick description of what makes a Newtonian and non-Newtonian fluid.
Newtonian fluid.
A fluid whose viscosity doesn't depend on gradients in flow speed. Gases and low-molecular weight liquids are usually Newtonian fluids.
non-Newtonian fluid.
A fluid whose viscosity changes when the gradient in flow speed changes. Colloidal suspensions and polymer solutions are non-Newtonian fluids.
So in a non-Newtonian fluid, doubling the speed that the layers slide past each other does not double the resisting force. It may be less than double or it may be more than double. The resisting force behind how hard it is too move these layers... Or in cooking terms stir it.
So which of these food and drink related items are non-Newtonian fluids ?
- Ketchup
- Milk
- Water
- Corn starch in a paste
- Gravy
- Yoghurt
- Orange juice
- Whisky
- Pie filings such as pumpkin or chocolate pie (technically a liquid/fluid because it will run out eventually, just very slowly target liquid tar being a liquid not a solid)
- Custard
Not an easy one this one and it will take a little working out, but quizzes are not meant to be easy and this for me, is not too difficult to work out whereas the cryptic crossword clues on food and drink just have me totally defeated!