Continuing last month’s topic of temperature effects on measurements, what about temperature compensation? Some measuring systems claim increased accuracy with the usually optional temperature compensation. What’s that? What’s it supposed to do? And does it do what it claims to do?

Remember that parts, especially metals, expand when heated. When the length of that part is being measured, it’s important to take temperature-related influences into account. A common example is handling gauge blocks with tweezers to avoid transferring heat from your hands to the blocks.

Temperature-induced changes in the length of a part depend on the magnitude of the change in temperature and the rate of change. You probably recall that the temperature of a gas changes faster than that of a liquid, which changes faster than that of a solid. In other words, it takes longer to raise or lower the temperature of anything solid than it does liquids or gas. This means that if you measure the air near a part, you don’t really know the temperature of the part. We’ll get to why this matters a little later.

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