3 ms·

I think a lot of people who are skeptical of this story just don't realize that they appended to be surrounded by people who have developed unusually accurate p

by rz2k 13y ago

I think a lot of people who are skeptical of this story just don't realize that they appended to be surrounded by people who have developed unusually accurate physical models. I recommend browsing Amazon reviews of (non heat pump) electric heaters for statements about which ones are more efficient. (The less efficient one produce more waste heat?) Because there are few consumer products that exercise people's understanding of gravity, basic thermodynamics might be a good proxy. However the real point of the article isn't all the misconceptions that must be "plucked out" one by one, but the struggle of trying to figure out how to encourage students to form more comprehensive models. I'd also add that an important goal in teaching is students' facility in applying principles, and confidence to question intuition and consensus.

jhonkola 13y ago
Well, in case of electric heaters used to heat a home the efficiency should really be measured in terms of "how much electricity is consumed if the heated room is kept at constant 20C measured at e.g. center of room". This is somewhat dependent on the quality of the thermostat controlling the heater. Then, I think that there are some real differences found in the efficiency of the heaters.
- alanctgardner2 13y ago
  I don't think energy efficiency is really so critical as the control system: how much steady-state error is there, and how quickly can it initially heat the room? Overheating the room is obviously a bit of a waste of power, but it's also uncomfortable.
- quasse 13y ago
  If you're still talking about electrical heaters here, there's literally no where for the energy used to go other than into heat for the room. If you have two 1000w heaters, one made from a potato and ten clothes hangers and the other made from the highest quality materials known to man, they will still both heat a room the same amount. Granted, one might have a better fan or more airflow and might therefore provide a more even heat distribution in the room, but they will both be providing the same amount of heat to the interior of the room. That's just how energy balances work. If 1000w is flowing from the plug into the heater and it's not being stored anywhere in the heater itself there's nowhere for it to go but into heat for the room.
rz2k 13y ago
>don't realize that they appended to be surrounded by autocorrected, should have been: >don't realize that they happen to be surrounded by

by rz2k 13y ago

jhonkola 13y ago

Well, in case of electric heaters used to heat a home the efficiency should really be measured in terms of "how much electricity is consumed if the heated room is kept at constant 20C measured at e.g. center of room". This is somewhat dependent on the quality of the thermostat controlling the heater. Then, I think that there are some real differences found in the efficiency of the heaters.

alanctgardner2 13y ago
I don't think energy efficiency is really so critical as the control system: how much steady-state error is there, and how quickly can it initially heat the room? Overheating the room is obviously a bit of a waste of power, but it's also uncomfortable.
quasse 13y ago
If you're still talking about electrical heaters here, there's literally no where for the energy used to go other than into heat for the room. If you have two 1000w heaters, one made from a potato and ten clothes hangers and the other made from the highest quality materials known to man, they will still both heat a room the same amount. Granted, one might have a better fan or more airflow and might therefore provide a more even heat distribution in the room, but they will both be providing the same amount of heat to the interior of the room. That's just how energy balances work. If 1000w is flowing from the plug into the heater and it's not being stored anywhere in the heater itself there's nowhere for it to go but into heat for the room.

rz2k 13y ago

>don't realize that they appended to be surrounded by autocorrected, should have been: >don't realize that they happen to be surrounded by