Metric System - Jenny Hendricksjennyhendricks.weebly.com/uploads/1/6/5/4/16542686/... ·...
Transcript of Metric System - Jenny Hendricksjennyhendricks.weebly.com/uploads/1/6/5/4/16542686/... ·...
Length
Definition
– The distance between two points along a
straight line
Units of Measure
– Meters (m) – base unit
Measuring track distances (100m dash)
– Kilometers (km) – large distances
Measuring distances between cities
Length (cont.)
Units of Measure
– Centimeters (cm) – small lengths Measuring dimensions of a textbook
– Millimeters (mm) – small lengths Measuring the width of your pupil
– Smaller units Micrometers (m) or nanometers (nm) – measuring the size of cells
Tools for Measurement
– Metric ruler or meter stick
Volume of Liquids
Definition
– The amount of space an object occupies
Units of Measure
– Liters (L) – base unit Measuring soda bottles (2L bottles)
– Milliliters (mL) – small volumes Measuring liquid in eye droppers
Tools for Measurement
– Graduated cylinder – measure at the bottom of the curve, called the meniscus
Volume of Solids
Definition
– The amount of space an object occupies
Units of Measure
– Cubic centimeters (cm3)
– 1 cm x 1 cm x 1 cm
– 1 cm3 is equal to 1 milliliter (mL)
– 1 m3 is equal to 1000 liters (L)
1 cm 1 cm
1 cm
Volume of Solids (cont.)
Tools for Measurement
– For rectangular solids, use a ruler
Volume = Length x Width x Height
– For irregular solids, use a graduated cylinder
to see how much volume of water is displaced
Fill a graduated cylinder half full and measure the
original volume
Place the solid (rock, marble, etc.) in the cylinder
and measure the new volume
Subtract the original volume from the new volume
to get the volume of the solid in cm3 or mL
Mass
Definition
– The amount of matter inside an object
– The mass of an object does NOT change
based on location
– Weight, on the other hand, does change
based on location (due to gravitational forces)
Mass (cont.)
Units of Measure
– Gram (g) – base unit Measuring mass of coins or small rocks
– Milligram (mg) – smaller masses Measuring amounts of medicine (500 mg)
– Kilogram (kg) – larger masses Measuring large fossils
– Metric ton (t) – really large masses Equal to 1000 kg or 1 Megagram (Mg)
Measuring mass of a dinosaur
Mass (cont.)
Tools for Measurement
– Triple beam balance
The instrument has 3 beams that are used to
measure objects
– 10g beam
– 500g beam
– 100g beam
Mass (cont.)
Tools for Measurement
– Triple beam balance
Steps to Operate the Balance
– Set all the beams to zero
– Place an object on the pan
– Start with the heaviest beam (500g), then move to the
next heaviest beam (100g), and finally to the lightest
beam (10g)
– Slide riders across each beam until the beam tips
– Use the lightest beam to balance the pointer at zero
– The mass of the object is the sum of the readings from
each beam
Density
Definition
– The relationship between an object’s mass
and it’s volume
– The mass per unit volume of a substance
– Density = Mass/Volume
Units of Measure
– Grams per milliliter (g/mL) – base unit
– The density of water is 1 g/mL
– 1 gram of water occupies 1 milliliter of volume
Density (cont.)
If an object is more dense than water, it
will sink
– A rock, an anchor
If an object is less dense than water, it will
float
– A piece of wood, a plastic bottle
Temperature
Definition
– A measurement of how hot or cold something
is
Units of Measure
– Degrees Celsius (°C) – the unit we will use
Scale was set so 0°C equaled the freezing point of
water and 100°C equaled the boiling point of water
100 equal divisions between 0°C and 100°C
Temperature (cont.)
Units of Measure
– Kelvin (K)
Kelvin, a British physicist, wanted a temperature
scale with an absolute zero, below which
temperatures did not exist
Absolute zero is estimated to be 0 K
To convert from Celsius to Kelvin, add 273 to
Celsius temperature
Tools for Measurement
– Celsius thermometer