Equipment And Measurement
SI Units are... International Standards Abbreviated SI from the French Le Systeme Internationale d’Unites
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, or China, or any other country in the world. This allows us to share data.
Putting It All Together… prefix symbol unit centi- c m meter (0.01) hundredth of a meter milli- L liter m (.001) thousandth of a liter kilo- k g gram (1000) thousand grams
SI Units for Measurement Used in Science Type Base Unit Tool Metric ruler Measured in meters (m) Length Graduated cylinder Volume Measured in Liters (L) L x W x H Mass Measured in grams (g) Balance Temperature Thermometer Measured in degrees Celsius (OC) Clock Measured in seconds (s) Time
Metric Conversions Base Unit Deca10 deci .10 centi.01 Hecto 100 milli .001 Kilo 1000
Let’s Practice……. 36 cm = ___ m 28 mL = ____ L 5.25 m = _____ mm 480 mg = ____ g
6 5 Using a Ruler When measuring an object with a ruler, never start with 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. 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.
Reading the Meniscus When measuring liquid volume in a graduated cylinder, a meniscus often forms where the liquid ends. graduated cylinders 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 mL.
Read these liquid volumes in mL: A. B. 76.0 mL 11.5 mL