Metric System An Overview of the Concepts of Mass, Volume, Length, Temperature, and Density
Length Definition The distance between two points along a straight line Meters (m) base unit Measuring track distances (100m dash) Kilometers (km) large distances Measuring distances between cities
Length (cont.) 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 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 Cubic centimeters (cm 3 ) 1 cm x 1 cm x 1 cm 1 cm 3 is equal to 1 milliliter (ml) 1 m 3 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 cm 3 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.) 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 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 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.) 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