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Measurement is a description using numbers. The SI system of units provides a worldwide standard of measurement. Chapter 2: Measurement. 2.2 SI Units brainpop -measuring matter. SI Units: The International System. SI Units: The International System.
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Measurement is a description using numbers. • The SI system of units provides a worldwide standard of measurement. Chapter 2: Measurement 2.2 SI Units brainpop-measuring matter
SI Units: The International System • The SI system is used worldwide so that everyone is measuring quantities in the same way. • SI units are related by multiples of 10 • Ex: to rewrite a kilogram measurement in grams, multiply by 1000. • 5.67 kg x 1000 = 5670 grams • Move decimal 3 places to the right • Recall KHDUDCM
SI Units: The International System SI Base Units
SI Units: The International System • LENGTH • The meter is the SI unit of length. 1 m is about the size of a baseball bat. Rooms and buildings are also measured in meters. • Smaller objects are measured in centimeters. A twenty dollar bill is cm long. • Very small objects such as blood cells, bacteria and viruses are measured in micrometers (millionths of a meter) and nanometers (billionths of a meter) • DISTANCE • Distance is measured in kilometers. The distance from New York to Los Angeles is, 4,501 km. (1 mile = 1.6093 km. About how many miles is a 10K race?) • Metric conversion calculator
SI Units: The International System • VOLUME • The amount of space an object occupies is its volume. • The cubic meter is the SI unit of volume. (m3) Smaller volumes are measured with a cubic centimeter (c3 or cc) • To find the volume of a square or rectangular object, measure its length, width and height, then multiply them together. • *What is the volume of your textbook? • A liter is a measurement of liquid volume. A cube 10 cm by 10 cm by 10 cm can hold 1000 cm3 of water which is equal to 1 liter. (L) • VOLUME BY IMMERSION • Refer to example in book on page 52, ice cubes in water. • To measure the volume of an irregular object, start with a known volume of water and immerse (or drop in) the object. The increase in the volume of water is equal to the volume of the object.
SI Units: The International System • MASS • The mass of an object measures the amount of matter in the object. The kilogram is the SI unit for mass. One liter of water has a mass of about 1 kg. Smaller masses are measured in grams. A large paperclip has a mass of about 1 gram. • Mass is measured with a triple-beam balance. The balance compares an object to a known mass. • Mass depends only on the amount of matter in an object. • WEIGHT • Weight is a measurement of force. Weight and mass are not the same. • Weight depends on gravity which can change depending on where the object is located. A spring scale measures how a planet’s gravitational force pulls on objects. • *What would happen to your mass and weight if you visited the moon?
SI Units: The International System • TEMPERATURE • The physical property of temperature is related to how hot or cold an object is. • Temperature is a measure of the kinetic energy, or energy of motion of the particles that make up matter. • The higher the temperature, the more kinetic energy an object has. • The SI unit of temperature is kelvinbut Fahrenheit and Celsius are the most common scales used on thermometers and classroom laboratories. • Kelvin starts at 0, Fahrenheit and Celsius do not. • TIME AND RATES • The SI unit of time is the second. (s) Time is also measured in hours. (h) • A rate is the amount of change in one measurement in a given amount of time. • Ex: Speed is the distance traveled in a given amount of time. Speeds are often measured in kilometers per hour (km/h)