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Scientific Measurement

Scientific Measurement. The Metric System. An easy way to measure. Measuring. The numbers are only half of a measurement How wide is the room? It is 10. 10 what? Numbers without units are meaningless. What are units anyways?.

joseph-richards
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Scientific Measurement

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  1. Scientific Measurement

  2. The Metric System An easy way to measure

  3. Measuring • The numbers are only half of a measurement • How wide is the room? It is 10. • 10 what? • Numbers without units are meaningless.

  4. What are units anyways? • A unit is a particular physical quantity, defined and adopted by convention, with which other particular quantities of the same kind are compared to express their value.

  5. The system we use • How many ounces in a cup? • 8 • How many ounces in a pound? • 16 • How many feet in a yard? • 3 • How many feet in a mile? • 5,280

  6. The SI System • Le Système International d’Unités • Easier to use because it is a decimal system • Every conversion is by some power of 10. • A metric unit has two parts: a prefix and a base unit. • A prefix tells you how many times to divide or multiply by 10.

  7. Base Units • Mass - gram (g) • Length – meter (m) • Temperature - kelvin (K) • - Celsius (C) • Time - second (s) Derived Units • Area – square meter (m2) – length x width • Volume – cubic meter (m3) – length x width x height

  8. yotta (Y) = 1024 zetta (Z) = 1021 exa (E) = 1018 peta (P) = 1015 tera (T) = 1012 giga (G) = 109 mega (M) = 106 kilo (k) = 103 hecto (h) = 102 deka (da or D) = 101 deci (d) = 10-1 centi (c) = 10-2 milli (m) = 10-3 micro (m) = 10-6 nano (n) = 10-9 pico (p) = 10-12 femto (f) = 10-15 atto (a) = 10-18 zepto (z) = 10-21 yocto (y) = 10-24 Metric Prefixes

  9. Prefixes • Prefixes always mean the same thing! • Kilo- 1,000 • Hecto- 100 • Deka- 10 • ***Base = 1*** • Deci- 0.1 or 1/10 • Centi- 0.01 or 1/100 • Milli- 0.001 or 1/1000

  10. k h D d c m Converting • how far you have to move on this chart, tells you how far, and which direction to move the decimal place. • The box is the base unit, meters, Liters, grams, etc.

  11. k h D d c m Conversions • Change 5.6 m to millimeters • starts at the base unit and move three to the right. • move the decimal point three to the right 5 6 0 0

  12. 1 km = 1000 m 1 dm = 0.1 m 1 cm = 0.01 m 1 mm = 0.001 m 1 mm = 10-6 m 1 nm = 10-9 m 1 kg = 1000 g 1 dg = 0.1 g 1 cg = 0.01 g 1 mg = 0.001 g 1 mg = 10-6 g 1 ng= 10-9 g Metric system

  13. Measuring Temperature • Celsius scale • water freezes at 0ºC • water boils at 100ºC • body temperature 37ºC • room temperature 20ºC - 25ºC

  14. Measuring Temperature • Kelvin is always bigger • C = K -273 • K = C + 273 • Kelvin starts at absolute zero (-273 ºC) • Kelvin can NEVER be negative!!!!!!!!!!!!

  15. Measuring Temperature Fahrenheit is always bigger F = C (9/5) + 32

  16. Volume – a derived unit • Volume is the amount of space an object occupies • Calculated by multiplying L x W x H • It is also possible to find the volume of an object by measuring the volume of water that it displaces • 1 mL = 1 cm3

  17. Types of measurement • Quantitative - objective; most people would get nearly the same answer - use numbers to describe • 4 feet • 100ºF • Qualitative - subjective; personal opinion may influence answer - use description without numbers • extra large • hot

  18. Scientists prefer: • Quantitative - easy check • Easy to agree upon, no personal bias • BUT, the measuring instrument limits how good the measurement is.

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