Science that makes you cringe

[T42]

My daughter works in a place that i.a. makes electronic components.  Last week when checking the spec for a coil she found that a departed colleague had calculated the length of wire needed as the wattage divided by the circumference.

[citoyen]

Mark Radcliffe on the radio this morning was talking about making flasks of tea. His hypothesis was that making two cups at a time and putting one in a flask for later saves energy by not having to boil the kettle twice.

Surely X amount of water requires Y amount of energy to boil regardless of whether you boil it all at once or in separate batches?

I suppose there are perhaps some losses due to inefficiency, but does boiling all the water at once reduce those inefficiencies at all?

Must admit I don’t know the answer to this. He may be making a perfectly good point.

[LittleWheelsandBig]

Speculation: Some people don’t boil exactly the right amount of water in a kettle. Better to boil excess water once, rather than twice.

[ian]

I doubt it makes much impact, boiling a kettle is resistive heating, so the majority of the energy goes into the liquid (and a little into the kettle itself). Most of the loss will be to steam each time you boil (getting a fancy kettle that warms to 95 degrees is probably smarter). I think someone calculated the actual costs of boiling a kettle and it wasn't really much.

Plus he's a Radio DJ, so can probably afford to boil a kettle.

[T42]

He's losing heat when he puts the second cup into the thermos unless he uses more energy to pre-heat it, and while tea is in there it will lose volatiles into the air above it, so that the second cup will not be as good as the first.

But then he's a radio DJ...

[Diver300]

Surely X amount of water requires Y amount of energy to boil regardless of whether you boil it all at once or in separate batches?

I suppose there are perhaps some losses due to inefficiency, but does boiling all the water at once reduce those inefficiencies at all?

There are losses from heating excess water and the kettle itself, and some losses from the kettle shutting off after the water boils.
The thermos will lose heat, but the tea drinker may accept tea made with not-quite-boiling water (YMMV) and therefore heat lost from the thermos may not be extra electricity used.

[Giraffe]

I usually get the water in the kettle to +/- 25ml of the amount required, then heat it to the required temperature ('stat on kettle; overshoot on small amount ~10 C (lag due to poor convection in shallow water and also heat from the element after switching off) 70 C seems to be just right for coffee (of the instant, decaff, Waitrose variety) so 60 C is set.

[Cudzoziemiec]

Surely X amount of water requires Y amount of energy to boil regardless of whether you boil it all at once or in separate batches?

I suppose there are perhaps some losses due to inefficiency, but does boiling all the water at once reduce those inefficiencies at all?

There are losses from heating excess water and the kettle itself, and some losses from the kettle shutting off after the water boils.
The thermos will lose heat, but the tea drinker may accept tea made with not-quite-boiling water (YMMV) and therefore heat lost from the thermos may not be extra electricity used.

I think it's tea he's putting in the flask, not hot water.

[citoyen]

I think it's tea he's putting in the flask, not hot water.

It is indeed, he did specify that. One listener did suggest putting hot water in the flask then making the tea when you want it but Radcliffe declared this to be too much faff.

[citoyen]

Speculation: Some people don’t boil exactly the tight amount of water in a kettle. Better to boil excess water once, rather than twice.

It’s a fair point, but I don’t believe this was a factor in his thinking.

For the sake of this thought experiment, let us assume only the precise amount of water needed is being boiled.

(Fwiw, I usually fill the kettle by using the cup I will be drinking from to measure out how much water I need.)

[Kim]

You've got to factor in the energy required to wash out the flask you wouldn't otherwise be using.  Which may be substantial if there's milk involvement...

[PeteB99]

Meteorology that makes you cringe

Headline in todays Liverpool Echo

"Live updates as Liverpool hit by rain and wind from Hurricane Ian"

The Met chart I saw last night had Ian heading straight towrds South Carolina.

I suppose if you want to be charitable they might have meant the dregs of the one that hit Canada last week but that wasn't called Ian.

[ian]

I am everywhere.

[JonBuoy]

A potential supplier has told us that they want to use an alternative aluminium alloy to the one specified and that a material comparison website states that the two alloys have 93% of their average alloy composition in common.  It appears that that is mostly the aluminium part of the composition and it is just the alloying elements that differ.  Erm  -  I think that you will find that those are the ones that make all the difference 

[Giraffe]

So-called science re. development of an 'environmentally-friendly' anti-fouling paint for boats. Based on 'natural' silicone. At this point I was wondering how 'natural' silicone is. Read on and found that silicone is made from sand. Might be an extra letter somewhere.

[Bledlow]

A potential supplier has told us that they want to use an alternative aluminium alloy to the one specified and that a material comparison website states that the two alloys have 93% of their average alloy composition in common.  It appears that that is mostly the aluminium part of the composition and it is just the alloying elements that differ.  Erm  -  I think that you will find that those are the ones that make all the difference 

Er - what? Did you cross 'em off the list of potential suppliers?

I was just imagining a food product which is 7% sugar being replaced by one which is identical except for having 7% salt instead of the sugar. Honest, it's the same! Taste it!

[Kim]

I was just imagining a food product which is 7% sugar being replaced by one which is identical except for having 7% salt instead of the sugar. Honest, it's the same! Taste it!

Ah, the difference between traditional American and traditional Scottish cooking...

[JonBuoy]

A potential supplier has told us that they want to use an alternative aluminium alloy to the one specified and that a material comparison website states that the two alloys have 93% of their average alloy composition in common.  It appears that that is mostly the aluminium part of the composition and it is just the alloying elements that differ.  Erm  -  I think that you will find that those are the ones that make all the difference 

Er - what? Did you cross 'em off the list of potential suppliers?

I was just imagining a food product which is 7% sugar being replaced by one which is identical except for having 7% salt instead of the sugar. Honest, it's the same! Taste it!

I suggested that we find a better supplier who at least had a vague understanding of what they are talking about.

[hellymedic]

Good News article about how new Head has turned school around.

Wot no goggles on Head?
Nobody in protective clothes.
Girl's long hair is loose.
Open flame on Bunsen burner.

What sort of POSE is this?
What sort of education?

[Kim]

Pah, amateurs.  They haven't even arranged a row of conical flasks containing different coloured liquids on the windowsill.

[hellymedic]

Doesn't look like NEW, SHINY! school HAS windowsills...

[Tim Hall]

That could be a deliberate design feature, to stop people putting stuffs on them. Sloping window sills can be used for this purpose TAAW.

[Cudzoziemiec]

They're doing pretty well. They've got a flask of cherry coke, two tubes or urine, head has a grin, girl has a big smile ("I enjoy science. Setting fire to my hair is the best part.") and the boys have serious scientist faces.

I remember that in chemistry lessons we were supposed to leave the bunsen burners with a glowing flame like that (luminous?) so it was visible. Obviously gas was cheaper back then.

[Kim]

It's compulsory to have them in luminous flame mode for media photos, even if you're actively heating something or aren't doing anything that would require the use of a bunsen burner.

[Mrs Pingu]

The adult in the pic isn't doing a good job of leading by example regarding the goggles.