1. Unit 1 Measurements Measurements

2. All measurements in science are called variables and consist of a…… Number Unit Example: 3.4 m, 30 sec, 100 km/hr No Naked Numbers!!!

3. Basic units and prefixes Laboratory measurements follow SI units (Système international) Base units: meter (m), gram (g), liter (l) milli – prefix m - 1/1,000 of the base unit __1__ micro – prefix μ - 1/1,000,000 1000 nano – prefix n - 1/1,000,000,000 pico small

4. Laboratory Measurements We will use the following measurements Length: 1 meter (m) = 100 cm = 1,000 mm Mass: 1 g = 1,000 mg Volume: 1 L = 1,000 ml = 1,000,000 μl Temperature: Celsius: o C Time: Minutes or Seconds: min/sec

5. Converting Units: multiply with Conversion Factors – or simply know it 1 L___ 100 cm 1000 μl 1000 ml 1 m 1 ml

6. Practice How many L is 35ml? How many cm is 2,760 mm? How many μl is 0.85 ml? How many μl is 0.029 L?

7. Values in Science A. measured numbers represent values relative to visible, identifiable markings on instruments

8. b. estimated numbers – values between markings -makes measurements more precise Which is the more accurate reading? 52 ml 52.7 ml

9. Good measurements have one estimated number!!! 71.0 ml52.7 ml mm e mm e

10. measuring acc/pres and measurements