Chapter 1 Measurements

1. Chapter 1 Measurements 1.1 Units of Measurement 1.2 Scientific Notation

2. Measurement You make a measurement every time you • Measure your height. • Read your watch. • Take your temperature. • Weigh a cantaloupe.

3. Measurement in Science In science and allied health we • Measure quantities. • Do experiments. • Calculate results. • Use numbers to report measurements. • Compare results to standards.

4. Standards of Measurement • When we measure, we use a measuring tool to compare some dimension of an object to a standard. • Calipers are used to measure the thickness of the skin fold at the waist.

5. Stating a Measurement • In every measurement, a number is followed by aunit. • Observe the following examples of measurements:number + unit35 m 0.25 L 225 lb 3.4 hr

6. The Metric System (SI) The metric system is • A decimal system based on 10. • Used in most of the world. • Used by scientists and in hospitals.

7. Units in the Metric System In the metric and SI systems, a basic unit identifies each type of measurement:

8. Length Measurement • In the metric system, length is measured in meters using a meter stick. • The metric unit for length is the meter (m).

9. Volume Measurement • Volume is the space occupied by a substance. • The metric unit of volume is the liter (L). • The liter is slightly bigger than a quart. • A graduated cylinder is used to measure the volume of a liquid.

10. Mass Measurement • The mass of an object is the quantity of material it contains. • A balance is used to measure mass. • The metric unit for mass is the gram (g).

11. Learning Check In each of the following, indicate whether the unit describes 1) length 2) mass or 3) volume. ____ A. A bag of tomatoes is 4.6 kg. ____ B. A person is 2.0 m tall. ____ C. A medication contains 0.50 g Aspirin. ____ D. A bottle contains 1.5 L of water.

12. Solution In each of the following, indicate whether the unit describes 1) length 2) mass or 3) volume. 2 mass A. A bag of tomatoes is 4.6 kg. 1 lengthB. A person is 2.0 m tall. 2 massC. A medication contains 0.50 g Aspirin. 3 volumeD. A bottle contains 1.5 L of water.

13. Temperature Measurement • The temperature of a substances indicates how hot or cold it is. • In the metric system, temperature is measured on the Celsius scale. • On this thermometer, the temperature is 19ºC or 66ºF.

14. Learning Check Identify the measurement that has a metric unit. A. John’s height is 1) 1.5 yards 2) 6 feet 3) 2 meters B. The volume of saline in the IV container is 1) 1 liter 2) 1 quart 3) 2 pints C. The mass of a lemon is 1) 12 ounces 2) 145 grams 3) 0.6 pounds

15. Solution A. John’s height is 3) 2 meters B. The volume of saline in the IV container is 1) 1 liter C. The mass of a lemon is 2) 145 grams

16. Scientific Notation • A number in scientific notation contains a coefficient and a power of 10. coefficient power of ten coefficient power of ten 1.5 x 102 7.35 x 10-4 • Place the decimal point after the first digit. Indicate the spaces moved as a power of ten. 52 000 = 5.2 x 104 0.00378 = 3.78 x 10-3 4 spaces left 3 spaces right

17. Learning Check Select the correct scientific notation for each. A. 0.000 008 1) 8 x 106 2) 8 x 10-6 3) 0.8 x 10-5 B. 72 000 1) 7.2 x 104 2) 72 x 103 3) 7.2 x 10-4

18. Solution Select the correct scientific notation for each. A. 0.000 008 2) 8 x 10-6 B. 72 000 1) 7.2 x 104

19. Learning Check Write each as a standard number. A. 2.0 x 10-2 1) 200 2) 0.023) 0.020 B. 1.8 x 105 1) 180 000 2) 0.0000183) 18 000

20. Solution Write each as a standard number. A. 2.0 x 10-2 3) 0.020 B. 1.8 x 105 1) 180 000