Why does the coefficient for steel in expansion change with temperature?

[goonking]

Homework Statement

Homework Equations

ΔL = α L₀ ΔT

The Attempt at a Solution

I converted the 0.62 mm to meters, giving 0.00062 m

am I suppose to convert the degrees from Celsius to K? why is the coefficient for steel in K^-1? What does that even mean?

anyway, I converted C to K and answer I got was my initial length to be 0.180 meters

 

[Orodruin]

I converted the 0.62 mm to meters, giving 0.00064 m

0.00062 m

am I suppose to convert the degrees from Celsius to K? why is the coefficient for steel in K-1? What does that even mean?

You are dealing with temperature differences, not absolute temperatures. The temperature difference has the same numerical value in the Kelvin and Celsius scales, i.e., for temperature differences 1 K = 1 °C. When absolute temperatures are involved, it is essentially always necessary to use Kelvin unless an expression has been specifically tailored to the Celsius scale. In physics, Kelvin is a more natural scale than Celsius as it has zero at absolute zero.

And again, do not confuse C with °C (or ° C, which has no meaning, for that matter ...).

 

[physicsmama]

The coefficient for expansion means that steel expands 1.2 parts in 100,000 for each 1 Kelvin increase in temperature. A change of one Kelvin and one degree Celsius is the same, so you actually don't have to convert in this instance. Kelvin is a standard temperature scale used by the scientific community. Many tables of the coefficients of expansion for different materials are given in Kelvin, so that is probably why it was used.