Which instrument would you use to measure very small distances or thicknesses?

• A. Micrometer
• B. Ruler
• C. Beaker
• D. Thermometer

Answer: (A)

When you need to measure very small distances or thicknesses, you want a tool designed for high precision. A micrometer uses a screw mechanism that moves the spindle in tiny increments, allowing measurements in fractions of a millimeter. With the object between the spindle and the anvil, you close gently until it just contacts the item, then read the scale on the sleeve and the thimble to get an exact measurement. This combination of design and reading method gives far greater accuracy for small dimensions than other common tools.

Rulers are quick but imprecise for tiny distances, typically only to the nearest millimeter. Beakers are for measuring liquids by volume, not length. Thermometers measure temperature, not distance. So the micrometer is the best choice for measuring very small distances or thicknesses.