A 10,000 gallon tank changes 4 degrees. How much volume change is that?

A 10,000 gallon tank changes 4 degrees. How much volume change is that?

• A. 28 gallons
• B. 10 gallons
• C. 40 gallons
• D. 100 gallons

Answer: (A)

Temperature causes liquids to expand, so a tank’s liquid volume can change with temperature even if the tank itself stays the same size. The amount it changes is proportional to the tank’s current volume, the liquid’s volumetric expansion coefficient, and the temperature change. This relationship is written as ΔV = β × V × ΔT. In this problem, the tank holds 10,000 gallons and the temperature changes by 4 degrees. The problem uses an expansion coefficient for the liquid of about 0.0007 per degree Fahrenheit. Plugging in gives ΔV = 0.0007 × 10,000 × 4 = 28 gallons. So the volume change due to temperature is 28 gallons, which is 0.28% of the tank’s capacity. This matters in tightness testing because you must account for thermal expansion when interpreting pressure or volume changes; otherwise, you might mistake normal thermal expansion for a leak.

Temperature causes liquids to expand, so a tank’s liquid volume can change with temperature even if the tank itself stays the same size. The amount it changes is proportional to the tank’s current volume, the liquid’s volumetric expansion coefficient, and the temperature change. This relationship is written as ΔV = β × V × ΔT.

In this problem, the tank holds 10,000 gallons and the temperature changes by 4 degrees. The problem uses an expansion coefficient for the liquid of about 0.0007 per degree Fahrenheit. Plugging in gives ΔV = 0.0007 × 10,000 × 4 = 28 gallons. So the volume change due to temperature is 28 gallons, which is 0.28% of the tank’s capacity.

This matters in tightness testing because you must account for thermal expansion when interpreting pressure or volume changes; otherwise, you might mistake normal thermal expansion for a leak.