Which metal has the highest thermal expansion?

Hint:Thermal expansion is the tendency of matter to change its area, volume and density by changing its shape, which is in response to the change in temperature. The change occurs due to the fractional change in the linear dimension , length of the object. There are a large number of metals, ranging from no change due to temperature differences to large change due to temperature differences.

Complete answer:
The metal which has the highest thermal expansion coefficient is aluminum. It changes its dimensions most due to change in the temperature. Thermal expansion usually does not include change in phase. This phenomenon of change in length occurs due to following reason:

We know that Average molecular Kinetic energy depends on temperature and with increase in temperature, the constituent molecules begin to vibrate and they get spread out in different directions, thus the material expands.

A few applications of this property of aluminum having the highest thermal coefficient is : - Most of the utensils we use in our household is made up of aluminum, that is because it has a low density , is non toxic and has high thermal conductivity . It is also used in making cans, window frames and aeroplane making due to the above mentioned properties.

Hence,the metal that has the highest thermal expansion coefficient is aluminum.

Note:The property of malleability is not to be confused with thermal expansion. Also note that the important metals such as the metal having highest melting point, lowest melting point, highest boiling and such are to be remembered. The metal having the lowest thermal expansion is tungsten.