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National Hazard
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hotplate performance
Folks,
so that may look as a noob question (that's why I post it here), but I have that new hotplate/magnetic stirrer which is supposed to reach 280 °C.
However, I can't even bring 200 ml of water in a open beaker to boil while working outside. Is that par for the course (thermal loss is such that even
at 280 °C, the inner water cannot reach 100 °C), or is the doohickey defective?
Thanks!
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Ubya
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how many watts is the heating element? maximum temperature is not really a good parameter when talking of power
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Keras
National Hazard
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Quote: Originally posted by Ubya  | | how many watts is the heating element? maximum temperature is not really a good parameter when talking of power |
500 W
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Sulaiman
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I see your problem ... judgng by 48,2 you live in a field 
Even a small breeze can have a significant cooling effect,
try making a windshield / heat shield / insulation layer of aluminium foil
(or use anything convenient such as wood, metal or glass)
example;
CAUTION : Hobby Chemist, not Professional or even Amateur
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I don't, but my mother, at whose place I do my experiments, does indeed! Or rather, a small village surrounded by an ocean of corn fields. But you can
see a picture on the other message I posted this morning, about the chlorine generator.
| Quote: Originally posted by Sulaiman |
Even a small breeze can have a significant cooling effect,
try making a windshield / heat shield / insulation layer of aluminium foil (or use anything convenient such as wood, metal or glass)
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Thanks. You're right, I was thinking about that, but before giving in to such kludges (aluminium foil around a beaker?) I just wanted to know if that
was common or if my hotplate was just faulty.
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vmelkon
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I don't have a hot plate but I use to use a halogen bulb, 300 W, to boil water, in a RBF, 500 mL or 1 L in size. It took maybe 30 min to start to
boil. Using 2 halogen bulbs helped a lot.
For your hotplate, you could measure the current it uses.
The math is simple:
W/V = A
500 W / 120 VAC = 4.17 A
500 W / 240 VAC = 2.08 A
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Sulaiman
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Infrared water heating information
These two diagrams show the emission spectrum of heaters vs. temperature and the penetration depth of water vs. wavelength;
So a halogen lamp (c3000K) works, but not as well as a dull-red heater.
Almost all of the infra red of a heating mantle is absorbed in the first millimetre of water.
CAUTION : Hobby Chemist, not Professional or even Amateur
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Yttrium2
Perpetual Question Machine
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Hey, I thought my iirc. 180watt hotplate couldn't boil water, turns out the dial did infact move past the marking that I thought was the max...
A duh moment
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