# Temperature Outside Without Thermometer

1. Jun 8, 2014

### Chris914

Is there a way to determine the temperature outside without using a thermometer? Any formulas I could use?

2. Jun 8, 2014

### Nathanael

It's a bit like asking if there's a formula for how tall something is,

You just have to go and measure it.

(Maybe there are other things you could measure, and apply a formula to, that would tell you. I don't know much thermodynamics though. Is this what you were asking?)

3. Jun 9, 2014

### Simon Bridge

You could look at the ground - if it is sort-of whitish, then the temperature estimate is "cold" and if it is totally white then it is "very cold". OTOH if it is glowing orange, then it is "very hot".

You could put your hand on the window for a bit, then plunge it in bioling (or freezing) water - ans so estimate the temperature on a pain pain scale. As in: "It is excruciatingly cold today... but not as excruciating as it was 10mins ago can someone call me an ambulance thanks."

I suppose: you could use a spectrometer and point it at an object outside - the spectrum is related to the temperature.

Part of the point of PF is to help people learn to talk to scientists.
In science, any device (or combination of devices) which is used to find out the temperature of something is called a "thermometer". That is what the word means.

So you have pretty much asked if there is a thermometer that is not a thermometer...

But if you mean to ask if there is a way of determining the temperature without measuring something, the answer is "no".

4. Jun 9, 2014

5. Jun 9, 2014

### Simon Bridge

You mean: get someone else to use the thermometer?

6. Jun 9, 2014

### TumblingDice

I thought you pretty much covered all of the other options, and I couldn't resist.

7. Jun 9, 2014

### CWatters

Are you allowed to use a thermometer indoors? Do you know anything about the insulation properties of the building?

Perhaps you could measure the power required to keep the inside at say 20C and calculate the implied temperature gradient. It wouldn't be very accurate because heat loss also depends on wind and solar gain.

8. Jun 9, 2014

### SteamKing

Staff Emeritus
Do you have access to any crickets? There's a formula you could use if you have chirping crickets.

http://en.wikipedia.org/wiki/Cricket_(insect)

9. Jun 9, 2014

### syhprum

Last edited: Jun 9, 2014
10. Jun 9, 2014

### CWatters

11. Jun 9, 2014

### Simon Bridge

... I'm just amazed nobody has suggested using a barometer.

There is also watching a sleeping cat - the tighter it curls the colder it is.
Unless it's trying to psyche you out and wants you to think it's cold...

(If the cats look like Dahli clocks, then it is pretty warm.)

There is looking at a calendar and estimating the outside temperature via a table of mean seasonal variations.
That would be - taking advantage of the fact that others have used thermometers for a long time.

12. Jun 13, 2014

### PhysicoRaj

I've heard that the colour of blotting paper soaked and dried in a solution mixture of cobalt chloride and sodium chloride, depends on temperature. Much of chemistry in gen. phy.

13. Jun 13, 2014

### Orodruin

Staff Emeritus
By definition, a thermometer is a device used to measure temperatures. It is therefore impossible to determine a temperature without using a thermometer, although perhaps not a conventional one. All of the suggestions above are just different (and more or less precise) thermometers. I particularly fancy the cat-thermometer, even though it would seem to me that it would require extensive calibration before use.

14. Jun 13, 2014

### phinds

It also depends on how fat the cat is. Fat cats tend to be more content and feel less need to curl tightly, even if it is cold. They are also less reliable because they are often off at the bank counting their money.

15. Jun 14, 2014

### Simon Bridge

... or a way of getting someone else to use the thermometer.

I suspect this observation will be made several more times before the thread finally peters out.
Anyone suggested turning on the radio or the TV?

There's also a varient of the weather rock - if it has snow on it, it's "cold" and if it is melting, it's "hot".

To tell the temperature outside without going outside: put the thermometer outside and watch it through a window... if you mean not to use a thermometer like you get in a store, then use a thermometer you didn;t get in a store, and if you mean not to use the thermometer yoursef then get someone else to do it.

I think that covers all the bases.

An enormous amount of science lies in asking the question - once a question is asked properly, most of them are automatically answered. As written, the problem is under-specified - more information needed. I could have just put that at the start but that would have been boring.

16. Jun 14, 2014

:rofl: