4
votes
2answers
37 views

Does measuring the air temperature near a 21 lane asphalt highway impact measurements?

The official temperature in Sydney is measured at the Sydney Observatory. This is located near the city side of the Sydney Harbour Bridge - which is a major highway. My question is Does ...
2
votes
1answer
57 views

If hot air expands in all directions why is the balloon moving up?

A balloon is moving up. The hot air inside the balloon is expanding in all directions and cold air outside the balloon acts with force on the balloon from all directions (higher pressure force). Why ...
0
votes
0answers
42 views

What is the refractive index of air at high temperatures (> 200 °C)

Is there a method/formula to calculate the refractive index of air at high temperature (e.g. 400 °C - 800 °C)? I could only find formulas specified up to 100 °C and our physicist at university ...
0
votes
0answers
33 views

Techniques to cool gas to -100 celsius degrees

I am planning to design a scrubber system to separate CO2 and some other gases from a gas mixture. For this purpose, I thought to cool the gas below CO2's boiling point which is -57 Celsius. There are ...
28
votes
7answers
4k views

Is it possible to “cook” pasta at room temperature with low enough pressure?

It is known fact, that boiling point of water decreases by decreasing of pressure. So there is a pressure at which water boils at room temperature. Would it be possible to cook e.g. pasta at room ...
0
votes
2answers
435 views

Why do we feel a sudden chill?

When we are in a room, especially in some old houses, we feel this sudden rush of cold air. How does a strong air current arise and pass away so quickly?(lasts for about a second) I know air-currents ...
-1
votes
3answers
4k views

High and low pressure area and raining

In the high-pressure area it is mostly likely that there is sun. In low pressure area it is mostly likely that rain will occur. Because of the law that ...
3
votes
1answer
598 views

Local Mach number for an airfoil

I would like to know how to calculate the local Mach number on the upper surface of an airfoil given the ambient temperature, the local velocity on the airfoil surface, the freestream velocity, and ...
4
votes
2answers
3k views

Why would colder air disperse condensation on a car windshield?

The outside temperature was somewhere between the hot and cold that blows on the inside through the car's vents. I know the condensate is on my side because I can reach forward and write on it with my ...
18
votes
4answers
14k views

Why does the air we blow/exhale out from our mouths change from hot to cold depending on the size of the opening we make with our mouth?

Why does the air we blow/exhale out from our mouths change from hot to cold depending on the size of the opening we make with our mouth? It's not just a subtle difference, but significant in my ...