1.6 : Accuracy and Precision

Accuracy and Precision

In science, getting the right measurements is important. Accuracy and precision help make sure data is reliable and results make sense. But what do these words mean?

• Accuracy is how close a measurement is to the actual or correct value.
• Precision is how consistent your measurements are, even if they’re not exactly correct.

Think about throwing darts at a target. If your darts land close to the bullseye, that’s accuracy. If they land close together but not near the bullseye, that’s precision. If you get both, that’s the best!

Why Accuracy and Precision Matter:

Scientists need accurate and precise measurements to make sure their results are trustworthy. Imagine a doctor measuring the right dose of medicine, it needs to be both accurate and precise. Engineers measure distances in space, and even small errors can lead to big problems. Good measurements help us make better decisions, whether in a science lab or in everyday life.

Science and Engineering Practices (SEP): Obtaining, Evaluating, and Communicating Information
Scientists rely on accurate and precise measurements to ensure reliable data. You can practice these skills by analyzing and comparing measurement results.

Activity: Measure, Compare, and Discuss

• Pick an object and have all your friends measure its length with the same tool.
• Write down each measurement and find the average—this shows accuracy.
• Check if the measurements are close to each other—this shows precision.
• Talk about what might have caused differences and how to improve the results.

Crosscutting Concept (CCC): Scale, Proportion, and Quantity
The reliability of measurements depends on scale and precision. Small inaccuracies can lead to significant errors, especially when dealing with extreme sizes. Think about the following examples:

• If you measure a doorway a little off, it’s probably okay.
• If you miscalculate a medication dose, it could be dangerous.

Scientists use careful measurement techniques to avoid mistakes. Practicing these skills helps us collect good data and make smart conclusions in science.