CLASSNOTES: fill in blanks in class
MEASUREMENTS are different from ordinary OBSERVATIONS
describe physical properties
are exact(precise) and accurate (true)
use .......... and .......... (dimensions)
are obtained using instruments
are obtained by .......... object to something
are objective (not opinion)
tell the .......... of something
UNITS: Every measurement has one!
A number without a unit is like a naked number!
How do we decide on units?
.......... for example, day, year
..........: meter, foot, gram
To have a worldwide system of units, everyone must agree on a standard for the unit (1 object that has that exact measurement of that property) OR use a scale (several objects that each have an even number for that property) that all agree upon.
1 meter used to be a length of metal stored in the International Bureau of Standards in Paris, now it is defined as 1650763.73 times one wavelength of the orange light emitted by a Krypton-66 atom.
1 second is 9,192,631,770 periods of radiation of an atom of Cesium-83.
1 kg is the mass of a block of metal sealed away in a vault in France.
FOOT: Emperor Charlemagne's (800 AD) foot, later in 14th century England it was 36 barleycorns laid end to end.
POUND: A Stone in England
CARAT: the weight of a carob seed, used for gems.
MILE: 1000 double steps or paces by a Roman soldier
GALLON: Queen Anne of England's wine jug
CUBIT: length of an Egyptian man's arm from elbow to fingertip.
INCH: length of the tip of the first joint on a man's thumb
YARD: distance from nose to fingrtips of King Henry I of England.
FATHOM: distance from fingertip to fingertip on outstretched arms of a Viking.
ACRE: The area of the amount of land that two oxen could plow in a day.
KNOT: or 1 nautical mile per hour, how many knots of a rope could be fed out in a specific time by a sailor on a ship.
Invent and write down at least 4 more standards or scales for measuring physical properties... (NOT length or weight).
Make up units and give a standard, such as described above, or devise a scale for measuring a property like the examples from class:
Example: Fluffiness: scale of 1 to 10
my teddy bear is a 10, my table is a 1
Example: Temperature in degrees Celsius
freezing water is a 0, boiling water is an 100
Bouncability: compared to my favorite spongebob toy dropped from 1 meter.