Warm Up #2 What tool would you use to measure the volume of a rock? How would you do this?

Lesson 2: Measurement and Scientific Tools Nature of Science (NOS): Scientific Explanations

Essential Questions What is the difference between accuracy and precision? Why should you use significant digits? What are some tools used by life scientists?

Description and Explanation Description – a spoken or written summary of observations Qualitative description – uses your senses to describe an observation Quantitative description – uses numbers to describe the observation Explanation – an interpretation of observations

International System of Units SI Units – an internationally accepted system for measurement A prefix can be added to a base unit’s name to indicate either a fraction or a multiple of that base unit Based on powers of 10

Precision and Accuracy Accuracy – a description of how close a measurement is to an accepted or true value Precision – a description of how similar or close measurements are to each other

Significant digits – the number of digits in a measurement that are known with a certain degree of reliability. Includes all digits known for certain plus 1 estimated digit Rules (pg. NOS 15) 1. All nonzero numbers are significant. 2. Zeros between nonzero numbers are significant. 3. Final zeros used after the decimal point are significant. 4. Zeros used solely for spacing the decimal point are not significant. The zeros indicate only the position of the decimal point.

Significant Digits Activity With the person next to you determine which numbers are significant using the rules. 4.05 770.032 0.0025 1,500 0.500

Scientific Tools What are different tools that scientist use when they are performing a scientific investigation? Pass out Scientific Tools handout