Boiling point of water and atmospheric pressure..

[TVR1]

Evening folks...

Mods, please don’t dump this in science or food...

Just noticed the past few weeks but in particular this evening. Water is taking longer to boil than last week. This morning, 10 minutes to bring a 2 litre pan of water up to boil but just now, it’s only just there after 20.

Is it air pressure, and are we looking at a monster storm of some sort?

I know it’s really mad, but I’ve followed my cooking times for the past few months and whenever my potatoes boil quickly/water, nice day. Whenever timings gets thrown out, really long time, weather is fking freezing/inclement.

Anyone else noticed this?

[Darkslider]

Ambient temperature affects your incoming water temp too. Same reason your electric shower is weaker in winter, it needs to put more energy into heating the water to a given temperature so reduces the flow.

[Muddle238]

While the boiling point will be affected by pressure, I’m pretty sure the normal average range of atmospheric pressure (say, +/- 20HPa either side of the ISA standard 1013HPa) isn’t enough to make a noticeable difference in the time taken to boil a pan of water.

More likely your hob is on the blink!?

[Mave]

My initial thought was water temperature, but that doesn't really account for the water taking twice as long to boil - so if the timings are accurate and the water qualities the same, I wonder if there is some other influence? Op, is your hob electric or gas?

Edited by Mave on Monday 1st March 20:20

[Matthen]

The only thing that can really make a 10 minute difference, is quantity of water. It'd take a 2KW stove a maximum of 2 minutes extra, to heat water from 8C instead of 18C (assuming a 50% transfer of heat into the water... it's likely more like 80%). (Assuming the potatoes are always the same temperature going in).

4L instead of 2L? That's going to take twice as long to boil.

You haven't forgotten to put the lid on have you?

[Bill]

Low gas pressure or an electricity brown out depending on cooker type I suspect.

[FerrousOxide]

TVR1 said:

Evening folks...

Mods, please don’t dump this in science or food...

Just noticed the past few weeks but in particular this evening. Water is taking longer to boil than last week. This morning, 10 minutes to bring a 2 litre pan of water up to boil but just now, it’s only just there after 20.

Is it air pressure, and are we looking at a monster storm of some sort?

I know it’s really mad, but I’ve followed my cooking times for the past few months and whenever my potatoes boil quickly/water, nice day. Whenever timings gets thrown out, really long time, weather is fking freezing/inclement.

Anyone else noticed this?

Based on your observations it's nothing to do with atmospheric pressure. Low pressure (usually associated with "inclement"" weather) would make water boil at a lower temperature. So, all else being equal it'll boil quicker if there's a storm, as you wouldn't have to get it as hot before it boils.

There are far too many unknowns to give an answer here. How are you heating the water? Where do you draw the water from (living in an old, badly plumbed and insulated house means the water from my taps varies hugely in temp according to the weather)? Are you subconsciously cooking more when the weather's a bit stty? And why don't you want this in the science forum?

[Macneil]

(B1*V1)/T1 = (B2*V2)/T2.

Easy.

[67Dino]

One of the perils of climbing mountains is you can’t get a decent cup of tea, as the pressure is too low to get it properly hot. I gather at the top of Kilimanjaro water boils at about 80 C and on the summit of Everest about 68 C. Not that you care, frankly, as long as it’s a hot drink and you can catch your breath between sips.

But in both cases you’re talking significantly lower pressure than caused by weather at sea level.

[jet_noise]

Use the electric kettle to get the water boiling. Add to pan. Time & energy saved!