Question

why we not carry mercury thermometer in aeroplane and why in cars​

Answer 1

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Mercury and Aluminium really don't play well together. Well, depending on your point of view, you might say they play excellently together, but the outcome is you destroy the structure and strength of your aluminium.

Mercury and Aluminium really don't play well together. Well, depending on your point of view, you might say they play excellently together, but the outcome is you destroy the structure and strength of your aluminium.The problem with this is that much of the plane (including the fuselage) is made of aluminium, so having it be eaten away by mercury is a bad thing during the flight, and also a very bad thing for the value of the plane afterwards!

★ᴘʟᴇᴀsᴇ ᴍᴀʀᴋ ᴀs ʙʀᴀɪɴʟɪᴇsᴛ ᴀɴsᴡᴇʀ ᴀɴᴅ ғᴏʟʟᴏᴡ ᴍᴇ!!

Answer 2

Aeroplane

NO! Mercury is absolutely banned on all aircraft, even in checked luggage. ... It has to do with what happens when liquid mercury contacts aluminum, the main material in most aircraft. Mercury can cause aluminum to 'rust' as it were, which would weaken the aircraft to the point that it would break.

Car

Mercury is the only one in liquid state at room temperature. It's used in thermometers because it has high coefficient of expansion. Hence, the slightest change in temperature is notable when it's used in a thermometer. It also has a high boiling point which makes it very suitable to measure higher temperatures.