The Metric System and Tools of Measurement

Why measure? Why use units?Units: Invented so people could _________________The ancient Greeks first developed the FOOT (Hercules foot? Kings foot? Your foot?)The YARD was first developed for making clothes The MILE was developed by the Romans (The step of a Roman guard was about 2.5 feet; 1,000 double steps equaled one mile)Naturally, since everyone was different, much confusion ensued

The Metric SystemBase __________ systemBased on a base unit that corresponds to a certain kind of measurementLength = __________Volume = literMass = ___________Temperature = Degrees Celsius (Kelvin) Time = seconds Weight = NewtonsPrefixes plus a base unit make up a _____________ system unit.Example:Centi + meter = CentimeterKilo + liter = Kiloliter

Basic Tools of Measurement_________

Metric Ruler/Meter Stick

Graduated Cylinder

___________

Reading a balance:What is the mass of the small beaker located in your lab basket? Record that mass. Marble mass: ____________ ( )

MassThe measurement of the amount of __________ in an object

Units: (SI): gram, Kilogram, milligram

1 gram1 kilogram

Ruler and meter stick practice:Using a ruler, measure the length of the pencil found in your white container. Record your data.Pencil length: _________________ ( )

Using a meter stick, measure the length and width and height (from floor to top edge) of your table. Record this measurement. Table length: ___________Table width: ___________Table height: ___________

DistanceAn amount of ___________ between two things or peopleUnits: (SI) - meter, kilometer, centimeter Examples: Meter -Width of a Door1 Centimeter = Width of Your Finger1 Kilometer = 365 Football Fields1 Millimeter = width of pencil lead

Volume practice:Fill your graduated cylinder to the 25mL mark. Drop the marble into the cylinder (gently; do not splash). Record the new volume. V1= ________ ( )V1= ________ ( )Dump the water from the cylinder into your waste cup in order to retrieve your marble.Dry off your marble and place it back into your white container.Find the cylinder with colored liquid located at your table.Lift the cylinder above your nose, keeping your head still. Record the volume you see. V= ___________ ( )Lower the cylinder below your nose, keeping your head still. Record the volume you see. V= ___________ ( )

Meniscus curve in the surface of a liquid

Good measurementsRead graduated cylinder at eye levelRecord volume at the bottom of the meniscus*

VolumeThe amount of _________ an object takes upUnits: (SI): liter, millimeter, cm3

Measuring VolumeSolid VolumeMeasured with a ruler= Length x Width x Height (if definite shape)- Calculate the volume of your table.Show work: V= ___________ ( )(if irregular shape) use the Water Displacement Method (with Graduated Cylinder)Use displacement to calculate the volume of your marble (V2-V1) Show work: V= ___________ ( )

Liquid VolumeUse the Graduated Cylinder Measure from bottom of meniscus

Cylinder vs. BeakerFill your larger beaker to the 50mL mark. Pour the water into a graduated cylinder. Record the volume.V= ________ ( )Which piece of equipment do you think is more accurate?

Accuracy & PrecisionAccuracy- How well a set of measurements _________ a given data set.Precision- How _______ the measurements are within a set of data.

Accuracy and Precision Examples http://www8.nau.edu/chem/OnlineCourseMaterial/Cruickshank/worksheets/precisionaccuracy.pdf

Name:_______________Ticket Out of the DoorIn the Sports Center video, Drew Brees throws a football at a bulls eye. Are his throws accurate, precise, or both. Use your notes to support your answer.

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