Measurement in Science 1 Customary Units vs Metric

Measurement in Science 1

Customary Units vs. Metric Units Inches, Feet, Yards, Miles DISTANCE Meters Cups, Pints, Quarts, Gallons LIQUIDS Liters Ounces, Pounds, Tons ° Fahrenheit WEIGHT/ MASS TEMPERATURE Grams ° Celsius 2

What is a standard? It is an exact quantity that people agree to use for comparison. Why are measurement standards important? A meter in the U. S. is the same as a meter in France. 3

SI Units are. . . International Standards Abbreviated SI from the French Le Systeme Internationale d’Unites or the Common Name of the Metric System 4

Can you think about any situations that we use the Metric System in our everyday life – either home or at school? Name at least 3 examples: 1. Come on brain!! 2. 3. 5

Pros & Cons of Metric System Why should we use this system? • Pro’s – Easy: based on the use of ten – Conversions are easier - Just move decimal point – Used all over the world – not just USA • Con’s – History of conflict all over the world – People don’t want to change – Replacement cost of machinery too high 6

International Standard Units (SI) 7

Putting It All Together centi(0. 01) meter hundredth of a meter milli(. 001) liter thousandth of a liter kilo(1000) gram thousand grams 8

From LARGEST to smallest the easiest way to remember the prefixes is in a sentence……. . King Henry dances merrily down center main. Or. . King Henry doesn’t milk dairy cows on Mondays. Kilo- Hecto- Deka- BASE deci- Meter, Liter, Grams centi- milli- 9

Metric Conversions Step 1: Locate the DECIMAL POINT in the number that you need to convert. . 27 025 g = _____ cg Decimal Point Step 2: Mark the starting point (where the decimal point is in the original number) on the guide. Kilo- Hecto- Deka- BASE . deci- centi- milli 10

Step 3: Mark the ending point (where the decimal point is in the final number) on the guide with an X. Kilo- Hecto- Deka- BASE . deci- centi- milli- X This is the direction the DECIMAL will move. 27. 025 g = _____ cg 11

Step 4: Move the decimal point (. ) in the direction of the X. Stop moving the decimal when you reach the X. That’s how many places you need to move the decimal point in the original number. Kilo- Hecto- Deka- BASE . deci- centi- 1 X 2 milli- 27. 025 g = _____ cg 27. 025 g = _____ 2702. 5 cg 12

SI Units for Measurement Used in Science Length / Distance Metric ruler: Measured in meters (m) Volume Regular Shape – Length X Width X Height Measured in cm 3 Example: box, land, table tops Metric ruler: Irregular Shape – Displacement Method Final Reading – Initial Reading = Volume Measured in milliliters (m. L) Example: Liquids, rocks, marbles Graduated cylinder: 13

Continued - SI Units for Measurement Used in Science Mass Balance: Measured in grams (g) Temperature Thermometer: Measured in degrees Celsius (OC) Time Clock: Measured in seconds (s) 14

Density …the amount of mass in a given volume Formula to calculate Density: Density = Mass Volume Units are expressed as: - g/m. L – density of a liquid - g/cm 3 – density of a solid M D V 15

Using a Ruler When measuring an object with a ruler, never start at the “ 0” mark. Rulers are less accurate due to wear and tear at the ends. Begin at the 2, 4, 5 or 6 cm mark in order to get the most accurate mark. 5 6 What is the length of the red line? 6. 2 cm or 1. 2 cm The red line would be 1. 2 cm because the “ 5” is the starting point. 16 6. 2 – 5 cm = 1. 2 cm

Reading the Meniscus graduated cylinders When measuring liquid volume in a graduated cylinder, a meniscus often forms where the liquid ends. In order to read this liquid volume, you must be at “eye-level” to the level of the liquid. You take the reading at the BOTTOM of the meniscus. The liquid level is 36. 5 m. L. 17

Read these liquid volumes in m. L: A. 76. 0 m. L B. 11. 5 m. L 18