I’m a high school student in honor chem, and our teacher took like, half a semester trying to explain the difference. I still dont get it, but she gave up. If anyone has a good simple definition, please post it.
Sorry I cant help with the oven thing. We just got a new oven, but with the old one, we basically determined if the temp. was accurate by cooking meat for the suggested time at the suggested temp, and seeing if we got any firey stomach illnesses. It was generally very accurate. (or precise?!?!?!?)
I gotta question the accuracy of those! The freezer one reads somewhere near -30 degrees F, while the oven one insists it’s at about 115 F… and they’re sitting right next to each other!
Accurate is correct. To remember, think accu-right.
Precise is nitpicky. To remember, think pre-slice (into tiny increments).
Normally, when precision is mentioned, accuracy is assumed. A ruler graduated to the 1/32 of an inch is more precise than one graduated to the 1/8 of an inch, and its reading would be more precise and more accurate.
It is possible to have greater precision with less accuracy. Let’s say you have a yardstick graduated to 1/8", and I have a yardstick graduated to the inch. Then 6" of yours gets sawed off. Mine is accurate to within an inch, yours is inaccurate by 6" even though it’s precise to 1/8".
The actual temperature in the oven is 348.40 degrees. This is determined by a thermometer known to be accurate and precise to the hundredth of a degree.
Thermometer A is graduated to 5 degrees. It reads a little under 350 on its scale. One would guess the reading to be 348 or 349. It is accurate to the extent possible, but not precise even to the degree.
Thermometer B is graduated to 0.1 degree. It reads 348.5. It is slightly inaccurate, but its reading is more useful than Thermometer A’s. This is because its amount of inaccuracy is less than A’s amount of imprecision.
Thermometer C is graduated to 0.01 degree. It reads 342.61. Although precise to the hundredth of a degree, it is inaccurate by about 6 degrees. Its reading is the least useful of the three.
With correct-reading measuring equipment, more precision means more accuracy. But precision, in and of itself, does not assure accuracy.
Very true. However, there is a strong correlation between readability and accuracy. A 6.5 digit DVM, for example, will almost always have a higher manufacturer’s uncertainty than a 7.5 digit DVM, which will almost always have a higher manufacturers uncertainty than a 8.5 digit DVM.
Having said that, there is no guarantee a *particular * instrument w/ high readability will be accurate. If its internal reference drifts, the “zero” will be off no matter how many digits are displayed.
Does anyone have any more info on the temperature swings of an oven set on a constant temperature? It seems like it would be easy to measure, if you had a probe that had a display outside the oven.
I’m thinking electric would have larger swings because the element takes a bit to heat up, compared to the instant-on of gas.
As a matter of fact, this thread inspired me to calibrate my oven control last night. I found that for any set temperature in the normal range of the oven (300-450 F), the swing was a total of about 40 degrees. For example, 350 on the knob swings between 330 and 370.
This info is for my electric Frigidaire oven, using a probe-style cooking thermometer placed in the center of the oven on a piece of aluminum foil to keep the radiant heat of the element from skewing my results. The swing may be different in the center than wherever the oven’s sensor is. I’m curious about what that sensor may be seeing. I’ll have to find where it is and put my probe there to repeat the experiment.
For the record, the average temperature I measures was 15 degrees higher than the set point, and it was pretty consistent across the whole range.
Hah, you have my old one! I got rid of it, got a new gas stove and couldn’t be happier. My old one was about 30 degrees cold, at least, and more at high temps. No window.
This place was built in '97 and there are lots of construction grade items that are just begging to be upgraded. This thing has no clock or timer, no accuracy in oven temps 3 small burners and just 1 (1!) large burner. No window?!? That’s the least of its short comings…
