Hard waves and sound question

[persian52]

Homework Statement

Design an experiment to determine the temperature outside.

Materials:
2 blocks of wood
stop watch
Measuring tape

The Attempt at a Solution

I believe it has something to do with measuring the rate of flow of a viscous liquid down a ramp.
The colder the temperature, the less distance per second the fluid travels.
Once baselines are established at known temperatures, it would be a fairly reliable instrument.


BUT

the thing is we can't use any type of liquid!
we have to do it with all the materials we have and nothing else...

 

[Pythagorean]

my first impulse is to say thermal expansion, but I don't know what you'd need the stopwatch for. You could just leave one block outside and one inside for a really long time, but you'd also have to know the temp inside for this to work:

http://en.wikipedia.org/wiki/Thermal_expansion

But then, you're title has nothing to do with thermal expansion.

 

[persian52]

my first impulse is to say thermal expansion, but I don't know what you'd need the stopwatch for. You could just leave one block outside and one inside for a really long time, but you'd also have to know the temp inside for this to work:

http://en.wikipedia.org/wiki/Thermal_expansion

But then, you're title has nothing to do with thermal expansion.

i got ur point, true

 

[jtebb]

Not sure if anyone cares, but to measure the temperature outside with this equipment, one could determine the speed of sound, which varies with temperature according to v=332m/s + 0.59T, where T is the temperature in degrees celcius.

Using the equipment, clap the boards about 200m from a wall, and measure the time taken for the echo to return (a trip of 400m). To make more accurate measurements, set up a rhythm of clap-echo-clap-echo and measure multiple trips. The averaging will minimize start and finish reaction time delays. Counting 20 round trips for example, that's 20x400m = 8000m in whatever time is measured with the stopwatch. v=d/t will give you the speed of sound on that day. Then use the speed of sound equation and solve for T, the temperature.

Cheers!

 

[paranormal]

I would suggest performing a different experiment to determine the temperature outside, since using a viscous liquid may not be feasible. One possible experiment could be using the blocks of wood and measuring tape to create a simple thermometer. By placing the blocks of wood in different locations outside (e.g. one in the shade and one in direct sunlight), and measuring the length of the shadow cast by the blocks at different times of the day, we can calculate the temperature outside based on the angle of the shadow. This method relies on the fact that the length of a shadow changes with the angle of the sun, which is affected by temperature. The stopwatch can be used to measure the time it takes for the shadow to change, allowing for more accurate temperature calculations. This experiment can be repeated multiple times at different locations to ensure accuracy. Another alternative could be using the blocks of wood to create a simple heat transfer experiment, where one block is placed in the sun and one in the shade, and the temperature change of each block is measured over time. This can give an indication of the temperature difference between the two locations. Overall, the key in designing an experiment to determine temperature outside is to find a reliable and feasible method that can be replicated multiple times for accurate results.