Measurement. Part 1: The Metric System

Transcription

1 Measurement Part 1: The Metric System

2 Introduction Why do scientists measure things? Measurements help scientists do several things: They help scientists make observations with greater accuracy. They help scientists describe what they observed with more information.

3 The Metric System The metric system was created over 200 years ago. Before that, different countries used different measurement systems. It was all confusing! Around 1790, scientists in France developed a better system of measurement. It was a system based on multiples of 10.

4 The Metric System The metric system was created over 200 years ago. Before that, different countries used different measurement systems. It was all confusing! Around 1790, scientists in France developed a world system of measurement. It was a system based on the number 10.

5 The Metric System The metric system was created over 200 years ago. Before that, different countries used different measurement systems. It was all confusing! Slowly, every country began to use the metric system. By 1970, only 1 major country didn t use it The United States

6 The Metric System Countries who do not use the metric system:

7 The United States What does the United States use? The U.S. uses English units: feet, inches, pounds, quarts, Fahrenheit Other countries use metric units: meters, centimeters, grams, liters, Celsius

8 The SI System The metric system has been changed a little bit. We use a newer version of the metric system now, called the International System (SI). Scientists around the world use SI units to take measurements of length meter mass gram volume liter temperature Celsius second time

9 Why Is SI the Best? The SI system is the simplest system to learn and use everyday! Only 30 total units (instead of 100s) Based on the natural world No numbers to memorize Used by all scientists (even in the U.S.!) Based on multiples of 10

10 Length Length is the distance from one point to another. The basic SI unit for length is the meter (m). Smaller lengths are measured in: centimeters (cm) Longer lengths are measured in: kilometers (km) millimeters (mm)

11 Length Game! Pick the correct unit of length for each object! millimeter (mm) centimeter (cm) meter (m)

12 Mass Mass is how much matter an object contains. The main SI unit for length is the gram (g). Smaller masses are measured in: milligrams (mg) Larger masses are measured in: kilograms (kg)

13 Mass Game! Pick the correct unit of mass for each object! milligrams (mg) grams (g) kilograms (kg)

14 Volume - Liquids Volume is the amount of space an object takes up. The SI unit for the volume of liquids is the liter (L) Smaller volumes are measured in: milliliters (ml)

15 Volume Rectangular Solids Volume is the amount of space an object takes up. The SI unit for the volume for solids is the cubic centimeter (cm 3 ) cm L x x W cm x x H cm Volume! cm 3 Larger volumes are measured in: cubic meters (m 3 )

16 Temperature Temperature is the amount of heat something has. The unit for temperature is degrees Celsius ( o C) Some scientists use another scale: kelvins (K)

17 Time Time is how long an event takes. The SI unit for time is seconds (s) Shorter times are measured in: milliseconds (ms) Longer times are measured in: minutes (min) hours (hr)

18 Prefixes The SI system uses prefixes. Prefixes are simple words that change the meaning of the word that follows You have used prefixes in math class For example, how many sides in a triangle? pentagon? hexagon? octagon?

19 Using Prefixes Prefixes tell us something. Prefixes in the SI system tell us how many times larger or smaller a unit is from the base unit. Getting confused? Let s try an example

20 An Example kilogram mass (kg) hectogram dekagram gram (g) decigram centigram milligram (mg) grams 1000 grams (g) 100 grams 10 grams 1 gram 0.1 gram 0.01 gram gram

21 Another Example kilometer mass (km) hectometer dekameter meter (m) decimeter centimeter (cm) millimeter (mm) grams 1000 meters (g) 100 meters 10 meters 1 meter 0.1 meter 0.01 meter meter

22 Metric Conversions To change from one metric unit to another, we use the step method. Kilo (k) Hecto (h) Deka (dk) Base unit Deci (d) Centi (c) Milli (m) gram meter liter King Henry Died By Drinking Chocolate Milk

23 Metric Conversions For example: cm km? Kilo (k) Hecto (h) Deka (dk) Base unit Deci (d) Centi (c) Milli (m) left Now, just move the decimal 5 places to the left. Therefore, cm km

24 Any Questions?