My Chem lab professor said that we have to wait for things to cool to room temperature so we can obtain an exact measurement. I don't understand also why.

You are watching: Why does one never weigh a hot object


*

There's two factors why you need to wait for a continuous temperature to weigh something: one is that hot air is much less thick than cold air, and deserve to produce a buoyancy that often tends to lift the object up and also minimize its weight. Also, if you are heating somepoint to dry it out, water molecules will be released from the sample, changing the weight. You want to heat somepoint enough to rerelocate the water, and then wait for it to cool to room temperature to weigh.


In enhancement, I would certainly assume that there's the underlying motive of teaching repeatability and protocol. If you weigh somepoint while it's cooling down, you don't understand what the temperature is. If the temperature does end up affecting the information, you won't have the ability to account for it. If you let it cool to room temperature each time, then it's even more continuous and also leaves much less room for variation.


You need to weigh them at a reference temperature so that you deserve to also obtain their volume at the same temperature, and thus determine their density at that temperature.


They weigh the exact same amount, he's wrong.

Changing the temperature of somepoint just changes the weight if it adds points from or looses points to the setting, eg a warm glass weighs slightly much less than a cold glass because there is a thin film of water on all glass surdeals with at room temperature.

what is more most likely is that the scales are not meant to handle warm points and also the temperature will upcollection the device it supplies to recognize the weight (eg if it provides a spring the spring will soften once heated)


while I think the over explanations also have actually good elements to them, I think your last element is probably the key to this.


The lab equipment deserve to warp and also end up being damaged once exposed to high temperatures. This tools requirements to be sensitive sufficient to accurately meacertain things prefer weight, and so is somewhat fragile.

See more: Explain Why Can A Square Never Be A Trapezoid ? Always, Sometimes, Never

In enhancement, a warm object will constantly weigh even more than a cold object, even if the 2 objects are otherwise identical in eincredibly means, although the distinction is extremely small, and also much beyond your capacity to meacertain.


*

Exsimple Like I'm Five is the finest forum and also archive on the internet for layperson-friendly explanations.Don't Panic!