UNIT: MEASUREMENT

ACT-Based Science: Precision, Accuracy & Experimental Error Answer Key

SCIENCE Thinking Challenge:

A student measures a block as 10.2 cm using a ruler but the actual length is 10.5 cm. What is the percent error? (ACT Science Score: 20-23)

1.2%

2.9%

3.5%

5.1%

(Correct Answer: B – Percent Error = (|10.5 - 10.2| / 10.5) × 100)

A student uses a digital caliper and a ruler to measure the same object but gets different results. What is the most likely cause? (ACT Science Score: 24-27)

The ruler is always more accurate.

The caliper measures more precisely than the ruler.

The ruler has a lower resolution.

The caliper is likely broken.

(Correct Answer: B & C – Higher precision tool measures more accurately.)