Wikipedia:Reference desk/Archives/Miscellaneous/2017 October 19

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October 19

Electric Kettle vs. Electric Cooker

Trying to be cost effective so, which would the best solution to boil showering water (5-10 litres a day) and to make noodles (pouring the boiling water into a bowl filled with noodles and waiting for it to meet the expected result...)? 123.108.244.144 (talk) 17:55, 19 October 2017 (UTC)

The electric kettle is more efficient for boiling a small volume of water for the noodles because the heat is supplied in closer contact with the water, so less heat is wasted. The showering problem depends on your plumbing arrangements. Dbfirs 18:03, 19 October 2017 (UTC)

Heating water for cleaning through your abode's water supply is handled generally in two ways:

• through a Storage water heater whereby a heating element (usually running off of the heating system of your house; i.e. if you have natural gas heating, your water heater is often uses natural gas as well) heats water and stores the hot water in an insulated tank, then the water is released from that tank when you turn on the hot water spigot.
• Through a Tankless water heating system that heats the cold water supply on the way to your hot water spigot.

Storage tank systems used to be nearly universal, but on-demand tankless systems are becoming more common. --Jayron32 18:46, 19 October 2017 (UTC)

That is indeed the case in our countries, but is it true in Bangladesh? Dbfirs 19:13, 19 October 2017 (UTC)

Yes. It might be that neither is common, but there's still a shift going on from stored hot water to instant hot water (and a demand for greater electrical power, if for a shorter time). What is more popular in Bangladesh, and in other countries where water is fairly warm, current supply is limited and Life Is Cheap would be a "suicide shower" like this https://www.youtube.com/watch?v=cNjA0aee07k Andy Dingley (talk) 20:19, 19 October 2017 (UTC)

In context, and given that the question is about heating water externally to the shower, this may be the very simple system of a suspended bucket with a tap and nozzle attached - [1] Wymspen (talk) 22:11, 19 October 2017 (UTC)

Heating enough water for a shower using a device designed for cooking may be problematic. Some issues:

1) The small batches of hot water produced, if all collected in a larger container, may cool while the subsequent batches are heated.

2) If one person will be taking a shower while another heats water and adds it to the tank, this may work better, but the water flow rate may need to be quite low, and/or you may need to turn the water off from time to time to wait for more water to be heated. For example, wet hair and lather with shampoo, then turn off water and wait for more hot water to rinse.

3) One important factor is the temperature of the water to be mixed with the hot water. If the rest is cold, then you will need far more hot water. But, if the rest is room temperature, then much less hot water is needed to make it warm. So, I suggest you fill the tank ahead of time, like the day before, to allow it time to come up to room temperature first, if it's cold to begin with.

4) You might consider passive solar heating. That is, put the water out in black buckets covered with plastic wrap, in the sunlight, to heat up. Of course, this won't work well for a morning shower, but may work well in the afternoon or evening. This may be used exclusively, if hot enough, or in conjunction with electrically heated water, otherwise. StuRat (talk) 19:50, 21 October 2017 (UTC)

The required quantity might be heated in a large container on the electric cooker. Heat will be wasted because of the slow heating and the distance of the heating element from the water, but this might be more efficient because the water doesn't need to get as hot. The most efficient solution might be to boil several kettles at once, but these need to be on separate circuits to avoid overloading. Dbfirs 20:25, 21 October 2017 (UTC)

But then you have the problem of how to get one large container of hot water to the shower. Presumably it would be too heavy to carry, and dangerous if it sloshes, so you would need to fill smaller containers and carry those to the shower. This is why, in the olden days, baths were usually taken in the kitchen. StuRat (talk) 20:29, 21 October 2017 (UTC)

Agreed. I remember those days! Dbfirs 20:39, 21 October 2017 (UTC)

• Clear jugs heated in sun and partial cold showers: Focus on solar, rather than electric, bath water. Shower water could be heated in clear waterjugs, using greenhouse effect to collect heat inside jugs, but also place jugs flat on white or reflective surface in sunshine for hours. After dark, heat can be retained a few extra hours by blankets or towels over jugs. Remember cold washing could be acceptable for feet/legs, to conserve warm water for upper-body wash, and hair shampoo could use cold water at sinks, if body is overdressed in warmer clothes, and hair is dried fast. So, upper-body shower could be done in 2–4 US gallons (7.6–15.1 L) of warm water, by shampoo sepatately. -Wikid77 (talk) 08:37, 22 October 2017 (UTC)

• Some type of black object in the center of the jugs would prevent the light from passing through and out the other side. A few drops of water-soluble dye would work, too. This shouldn't dye the person who bathes with it, being water-soluble. StuRat (talk) 19:12, 23 October 2017 (UTC)

What's the highest speed limit at a traffic light in the world?

What about the US? Sagittarian Milky Way (talk) 19:41, 19 October 2017 (UTC)

It can't be very high, because of the need to be able to stop when it goes yellow-red. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:24, 19 October 2017 (UTC)

You could add intermediate light(s) (like an orange light) or a timer that shows seconds to red like New York City pedestrian lights. Of course just because you could doesn't mean it's been done. Also I don't drive but from sprinting 100 yards to beat the light I foresee that long countdowns to car reds might increase crashes. Sagittarian Milky Way (talk) 22:11, 19 October 2017 (UTC)

A Google search found [2] and [3] where the highest seen by the posters is 70 mph (113 km/h) outside Austin, Texas. PrimeHunter (talk) 21:37, 19 October 2017 (UTC)

• Here's the Google Streetview of a set of traffic lights on the Isle of Man A1 road at Marown, which has no speed limit at all. The Streetview car actually turned up on the scene in the immediate aftermath of a car crash. Smurrayinchester 08:01, 20 October 2017 (UTC)

I think Smurray has a winner then. You can't beat infinity. --Lgriot (talk) 14:27, 20 October 2017 (UTC)

Infinity +1. Lugnuts ^{Fire Walk with Me} 11:42, 21 October 2017 (UTC)

Infinity + 1 is still infinity. But you knew that. :) ←Baseball Bugs ^{What's up, Doc?} carrots→ 13:24, 21 October 2017 (UTC)

That's the problem with silly trivia questions like this. It presumes that concepts like "posted speed limits" are universal. It is important to note that in places without posted speed limits you often STILL can be stopped for speeding. --Jayron32 14:48, 20 October 2017 (UTC)

That's the "reasonable and proper" rule, akin to the "too fast for conditions" rule which applies even where there is a posted speed limit. ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:09, 20 October 2017 (UTC)

The question didn't ask or assume anything about places that don't have a speed limit, whether speeding is an offense there or not. A speed limit can't be the highest unless it exists; therefore such places are irrelevant. --69.159.60.147 (talk) 21:17, 20 October 2017 (UTC)

That's your personal opinion. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:36, 20 October 2017 (UTC)

As for how to give people enough time to stop, one way is to have flashing lights some distance in front that warn "TRAFFIC SIGNAL AHEAD". I've seen generic versions that always have flashing yellow lights, and I've also seen a version timed with the actual signal, so the flashing yellow lights only come on when you are likely to need to stop at the light ahead. StuRat (talk) 19:39, 21 October 2017 (UTC)

In the UK, traffic is generally slowed to 50 mph or less before it reaches lights, I couldn't find a written rule that this is so, but I can't think of an exception (the Isle of Man is not part of the UK). There is also one of these signs beforehand, if traffic is likely to be approaching fast. Alansplodge (talk) 23:36, 21 October 2017 (UTC)

I can think of 2 quite quickly: Copdock A14 interchange is approached from the south with National speed limit (70 mph here). Also Felixstowe dock spur roundabout from the North West. --Phil Holmes (talk) 11:14, 22 October 2017 (UTC)

Quite right, I stand corrected (see National speed limit. Alansplodge (talk) 12:02, 22 October 2017 (UTC)

FWIW, if you are only counting posted speed limits, our Speed limit suggests the highest possiblein the world is 140 km/h and highest possible in the US is 85 mph although I doubt either of these actually have traffic lights. Nil Einne (talk) 12:20, 24 October 2017 (UTC)