- #1

de_Sitter

- 5

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I'm trying to determine a way of calculating the thermal expansion of a volume of water. The formula I have come across is:

ΔV = βV

_{0}ΛT

The general consensus seems to be that water expands roughly 4% from 20°C to 100°C, or 4.2% from 4°C to 100°C (http://www.engineeringtoolbox.com/water-thermal-properties-d_162.html). Using β = 0.000214 as found on (http://www.engineeringtoolbox.com/cubical-expansion-coefficients-d_1262.html) the result of this formula is not around the expected 4% from 20 - 100°C. e.g. 25L gives ≈ 0.43 L increase.

Am I using the formula correctly? Some rudimentary examples use β as a constant, while others remark that β varies with temperature, but don't provide examples of using this in practice. Any suggestions would be appreciated.

Thank you.