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Science. Basic Measurements. Accuracy and Precision. Accuracy is how close your measurement is to the actual value. Precision is how close your measurements match each other. D. Distance or Length. This nickel is 2.7 cm. This slide is 7.7 cm. or is it?.
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Science Basic Measurements
Accuracy and Precision • Accuracy is how close your measurement is to the actual value. • Precision is how close your measurements match each other.
Distance or Length This nickel is 2.7 cm
or is it? 7.6 cm, always read with your eye perpendicular to the measurement.
Volume • When measuring with a graduated cylinder the measurement is read perpendicular to the graduated cylinder at the bottom of the curve of the liquid called the meniscus.
Mass • Record the measurement as displayed. Digital balances
Lab Time!!!!! • Divide up into three equal sized groups. • Each group will work at each station. • When complete we will compare and contrast measurements within and between the groups.
International System of Units • Aka, The Metric System. • Based on multiples of 10.
2.5 X 10 = • 2.5 X 10 = 25 • 0.75 X 1000 = • 0.75 X 1000 = 750 • 3.0 X 100 = • 3.0 X 100 = 300
350/10 = • 350/10 = 35 • 150/100 = • 150/100 = 1.5 • 103/1000 = • 103/1000 = 0.103
Money • Our monetary system is mostly based on multiples of 10. • 1000>100>10>1>0.10>0.01>0.001 • Check out these wonderful EXAMPLES!
0.001 0.01 X 10 =
0.01 0.10 X 10 =
0.10 1.00 X 10 =
___________________ X 10
X 10 _____________________
X 10 ____________________
Prefixes • Prefixes are used to change from one multiple of 10 to the next in the metric system. • We don’t measure tiny objects with large units or large objects with tiny units.
Everyday Metric Prefixes WHOA! That’s a lot of prefixes. But don’t be afraid, only a few are used in everyday common measurements. kilo hecto deka base deci centimilli 1000 100 10 1 0.1 0.01 0.001
Putting it all together • 7 Base metric units and abbreviations: • meter (m) • second (s) • Kilogram (kg) • Ampere (A) • Kelvin (K) or Celsius C • Mole (mol) • Candela (cd)
Once again, only a few are used in everyday life. • Meter (m) to measure length. • Kilogram (kg) to measure mass. • Liter (L) , a derived unit, to measure volume. • Seconds (s) to measure time. • Kelvin (K) and Celsius C to measure temperature.
If 1 meter = 10 decimetersand1 decimeter = 10 centimetersthen how many centimeters make up 1 meter?
If 1 meter = 10 decimetersand1 decimeter = 10 centimetersand1centimeter = 10 millimetersthen how many millimeters make up 1 meter?
That’s right!1 m = 10 dm/1 m X 10 cm/1 dm X 10 mm/1 cmwhich = 1000 mm
It’s the same for mass and volume 1 kg = 10 hg = 100 dag = 1000 g 1 L = 10 dL = 100 cL = 1000 mL
Is it now obvious that the SI or metric system is easier than the English system of units?
You must simply multiply or divide by a multiple of 10 to change from one size unit to another size unit.
Remember “All things are difficult before they are easy” ~Thomas Fuller