05 measurement
DESCRIPTION
TRANSCRIPT
Measurement
What is measurement?• The process of comparing the
quantity of an observable relative to a standard.
Example:– Measuring the length of pencil using a
ruler– Determining how heavy you are using a
weighing scale
How should measurements be reported?
• All measurements must be given with the correct units.
• All measurements must be given with the correct number of significant figures (sf’s).
English System of Measurement
• This system grew out of the creative ways that people measured for themselves. Familiar objects and parts of the body were used as measuring devices.
English System of Measurement
• This system grew out of the creative ways that people measured for themselves. Familiar objects and parts of the body were used as measuring devices.
English System of Measurement
• Unfortunately, these creative measuring devices allowed for different measurements to be obtained when different people measured the same items.
• Eventually, a standard was set so that all measurements represented the same amount for everyone.
Conversion within the English SystemLength:
12 inches (in) = 1 foot (ft)3 feet = 1 yard (yd)5280 feet = 1 mile (mi)
Weight:16 ounces (oz) = 1 pound (lb)2000 lb = 1 ton
Conversion within the English System
Capacity:3 teaspoons (tsp) = 1 tablespoon (tbsp)
16 tbsp = 1 cup (c)8 ounces (oz) = 1 c2 c = 1 pint (pt)2 pt = 1 quart (qt)4 qt = 1 gallon (gal)
International System of UnitsSysteme International des Unites
• This is the modern form of the metric system and is generally a system of units of measurement devised around seven base units and the convenience of the number ten.
• It is the world's most widely used system of measurement, both in everyday commerce and in science.
Advantages of SI over the English System
• More consistent measuring tools• Extensively used in science and
other related fields• Easier to convert units within the
system
SI Fundamental QuantitiesQuantity Unit (Symbol)
Mass (m) kilogram (kg)
Time (T) seconds (s)
Length (l) meter (m)
Temperature (T) kelvin (K)
Amount of Substance (n) mole (mol)
Luminous Intensity (I) candela (cd)
Current (I) ampere (A)
Conversion within the SI
What makes conversion between SI units is its extensive use of prefixes instead of arbitrary
SI Prefixes and EquivalentsPower of Ten Prefix Symbol
1024 yotta Y1021 zetta Z1018 exa E1015 peta P1012 tera T109 giga G106 mega M103 kilo k102 hecto h101 deca da
SI Prefixes and EquivalentsPower of Ten Prefix Symbol
10-1 deci d10-2 centi c10-3 milli m10-6 micro μ10-9 nano n10-12 pico p10-15 femto f10-18 atto a10-21 zepto z10-24 yocto y
Conversion within the SI
Time:1 hour (hr) = 60 minutes (min)1 minute = 60 seconds (s)time intervals shorter than a second uses the metric prefixes (e.g. ms, μs, ps)
Conversion within the SI
Temperature:K = °C + 273.15°C = K – 273.15
Conversion between English and SI1 inch = 2.54 cm2.2 lbs = 1 kg°F = 9/5 °C + 32°C = 5/9 (°F – 32)
Metric units:1 liter (L) = 1 000 milliliter (mL)1 mL = 1cm3
1000 L = 1 m3
fin
Convert the following observing proper units and correct number of significant figures.
1. 125 m ? Km2. 20.0 cm ? In3. 160 mi ? Km4. 25 kg ? Lbs5. 1560 mg ? kg
TEMPERATURE• The degree of the hotness or the
coldness of a body (layman).• The measure of the average kinetic
energy of the particles of a body.
The Temperature Scales• The Fahrenheit Scale - based on 32
for the freezing point of water and 212 for the boiling point of water
• The scale is divided into 180 equal intervals
• Dwveloped in the 18th-century by the German physicist Daniel Gabriel Fahrenheit
The Temperature Scales• The Celsius Scale – also called the
centigrade scale• Based on 0 for the freezing point of
water and 100 for the boiling point of water
• Invented in 1742 by the Swedish astronomer Anders Celsius
The Temperature Scales• The Kelvin Scale - the base unit of
thermodynamic temperature measurement in the International System (SI) of measurement
• An absolute temperature scale named for the British physicist William Thomson Baron Kelvin
• Its zero point is in absolute zero, the theoretical temperature at which the molecules of a substance have the lowest energy
Conversion (oF and oC)
• F = 9/5C + 32• C = 5/9(F - 32)
Conversion (oF and K)
• C = K - 273• K= C + 273
Seatwork: ½ Pad Paper1. 56.0 oC oF K2. 89 oF oC K3. Find the temperature at which the
reading in both the oF Scale and the oC Scale is the same? Show your solution.
4. Explain or discuss the 2004 definition of MEASUREMENT in not more than 5 sentences.