1. PHYSICS BASICS Science Measurements and Units

2. MEASUREMENTS Measurements consist of a number and a unit. Example 100 meters the number of units the unit

3. INTERNATIONAL SYSTEM OF UNITS (SI units) Developed for the sake of Consistency (minimize errors) Clarity (ease of understanding) Communication (sharing data)

4. BASE SI UNITS (standard units) Measured quantity

5. DERIVED UNITS Derived Units: Combinations of the 7 base units. Examples Area (length x width) m x m = m 2 Velocity (distance/time) = m/s 10 meters 5 meters 50 m 2

6. How to Measure? Know how to operate the measuring instrument Which unit(s) is represented? What does each tick mark represent? Are there multiple scales? Did you zero out the instrument (if possible) Be skilled and patient enough to measure with the greatest detail possible

7. What do the tick marks represent on a meter stick? What unit is represented by the smallest tick mark on the meter stick? m? dm? cm? mm? *

8. What do the tick marks represent on a meter stick? What is the measurement? In mm? 65 mm In cm? 6.5 cm In dm?.65 dm In m? 0.065 m?

9. ACCURACY Accuracy is the extent to which a measurement approaches the true value. Your Time: 2:05 pm Actual Time: 2:10 pm Your accuracy is off by 5 minutes

10. - The bull ’ s eye represents the true value. - The darts represent three separate measurements accurate less accurate these darts show good accuracy which paint ball mark is more accurate?

11. PRECISION Precision is the degree of exactness of a measurement. Based on the scale of the measuring instrument. Smallest tick marks represent millimeters (mm)

12. PRECISION VS. ACCURACY A — Good precision and accuracy B — Some accuracy and poor precision C — Good precision and poor accuracy D — Poor precision and accuracy ABCD

13. Discussion Question When shooting free throws, is it better to be precise or accurate?

14. It ’ s better to be accurate.