Measurement And the Metric System

1. 1 Measurement And the Metric System

2. History: 6 Units of Length began by using parts of the body: The English system began in… …yup, you guessed it: England Cubit length of a person’s forearm[earliest known measurement] Foot size of a person’s foot[usually the king’s or ruler’s] But, measuring things was important long before we had a ‘system’ Inch size of the middle bone of a person’s pinky finger

3. Units of volume began by filling objects with stuff and counting how many fit: 3 Grain fill a space with wheat/oat seeds and count them Carat same as above, but usingCarobseeds. Still used to measuretoday. diamonds

4. Today, in America, we use a standard system to measure length. 7 Length 1/12 1/36 1 1/72 1/7920 1/90080 12 1/3 1/6 1/660 1/5280 1/5280 3 1/220 36 ½ 72 6 2 1/110 1/880 7920 660 220 110 1/8 1/24 8 5280 63360 1760 880 1/3 3 190080 2640 15840 5280 24 ~ Not Listed: Mil, Link, Chain, Rod, Pole, Perch, & Hand

5. If we were to use this ‘standard’ English system in science class you would have to know what all of those measurements were, plus you would also need to know all of the measurements for the following: 5 We could be here all day!!! This would be crazy to try to memorize and use, so Let’s Not Do That! • Mass: • Pound, apothecary pound, ounce apothecary ounce, dram, apothecary dram, grain, carat, scruple, pennyweight, short hundredweight, long hundredweight, short ton, long ton… Power: Horsepower, inch-pound/second, foot-pound/second, yard-pound/second… • Energy: • calorie, Calorie, inch-pound, foot-pound, yard-pound, mile-pound… • Volume: • Gallon, liquid quart, dry quart, liquid pint, dry pint, fluid ounce, teaspoon, tablespoon, fluid dram, gill, peck, bushel, cubic inch, cubic foot, cubic yard, cubic fathom…

6. 3 The Beauty of the Metric System You can measure all of the things listed above using the following units: Meter (m) Length: Volume: Mass: Energy: Joule (J) Power: Watt (W) Liter (L) Gram (g)

7. Metric Meanings & Measurements The system of measurement used by most people around the world is called the International System of Units (SI). It is the modern version of the Metric System. The Metric system was invented in 1670 by a French Astronomer & Mathematician named Gabriel Mouton. The specific measurement “standards” of the meter, liter, & gram changed as science and technology improved. Today there are very exact specifications for each. These amounts were agreed upon by many nations (including the US) at the Treaty of Meter in 1875. 2

8. Length Definition: Length is a measurement from here to there. Tool: You measure length using a Meter Stick. cm 16.8 mm 30

9. Mass 6 Tool: You measure mass using a Balance. MASS IS NOT THE SAME AS WEIGHT Definition: Mass is the measurement of the amount of matter (stuff) in an object. The standard unit of mass is the Kilogram (grams are too tiny to be useful) • Conversions: • One Kilogram (Kg) is a little over two pounds {On EARTH} • 1 Kg = 2.2 lbs 132.5 grams 150.5 grams

10. Weight 5 The moon’s gravity is 1/6of that of the Earth’s. So, if you weighed 120 pounds on Earth and traveled to the moon what would happen? • Definition: Weight is a measure of how gravity affects mass. • (remember, Gravity is the force of attraction between any two objects) Tool: You measure weight using a Scale. Weight: Mass: 20 lbs The standard unit for measuring weight is the Newton IT WOULD NOT CHANGE!!!

11. Area 4 Definition: Area is the amount of flat space inside a set of boundaries. • Instructions: • Measure the Length of the object = L units • Measure the Width of the object = W units To measure area you have to combine two units of Length. 2m Tools: the same for measuring length (meter stick) 3m Multiply them together: 2m x 3m = 6m2 Area = ( L x W ) Units2

12. Volume 4 Definition: Volume is the amount of 3D space an object takes up. • Tools: • For Solids: use the same tools you would for length (meter stick) unless using Water Displacement(see later notes) • For Liquids: use a Flask, Beaker, or Graduated Cylinder • To measure volume: • For solids: • or • For Liquids: • combine three units of length • (L,W,H) useLiters

13. 7 Flask Beaker Graduated Cylinder

14. How to measure Volume: 4m 3m 2m 4 For solids : Volume = Length x Width x Depth 4m x 3m x 2m = 24 m3 For liquids you measure to the bottom of the Meniscus. The meniscus is the curve the surface of the liquid gets when it’s put into a glass container.

15. 5 36.5 ml 39.25 ml 73 ml

16. Measuring the volume of an Irregularly shaped solid object: Let’s face it; very few solid objects are perfect cubes. There is an extremely accurate method, though, of measuring the volume of nearly any solid object, regardless of shape. It fact, it was invented by Archimedes during the Greek Empire, circa 1500 BCE. This is known as Water Displacement. 3

17. 9 Water Displacement: Definition: When a solid object is placed into water it will displace(move) an amount of water exactly equal to its volume. Example: You need to find the volume of a small bag of decorative marbles. = 25 cc (or cm3) • Begin with ml of water in a Graduated Cylinder. • Add the marbles to the graduated cylinder. • The final level of the water is ml. • The marbles then have a total volume of: 20 But, we don’t measure solids in ml, so we need to convert it to cm3 (or cc). This is the conversion ever. 45 easiest • 45ml – 20ml = • 25 ml 1 ml = 1 cc

18. Temperature 9 • Note: The SI temperature scale is known as Kelvin (°K). It is the preferred temperature measurement scale for scientists. We will be using Celsius (°C). They are exactly the same scale, but the Kelvin temperature is 273.15° higher than the Celsius. • (for reasons I’ll explain in a second) Definition: Temperature is a measurement of how fastatoms are moving, or in general, how hot or cold something is. The actual temperatures change depending on the material, but when atoms are moving very, very fast matter tends to be in the form of a gas. As atoms slow down that “state” changes into a liquid. If atoms are slowed down even more we get a solid. Temperature is measured in Degrees. ( ° ) • Important • Temperatures: Water boils at 100 °C • Water Freezes at 0 °C Tool: You use a Thermometer to measure temperature. Water Steam Ice

19. Temperature 1 There is a theoretical temperature where atoms STOP moving. It is called Absolute Zero. They know what the temperature is, but have never been able to reach it. No one knows what would happen to matter at this temperature.

20. Thermometer 3 30°C -5°C

21. 8 Human Body Temp? Boiling water? Ave. Room Temp? Number Bank 37 100 Water Freezing? 32 98.6 0 20 70 212

22. Density 12 Definition: The amount of Mass a material has in a certain Volume. VERY HARD QUESTION: Would a rectangular block measuring 10 meters x 2 meters x 1 meter, with a mass of 1000 Kgfloat? Explain. Equation: Density = Mass / Volume Tool: You use the same tools for measuring volume & mass.  A cube that is 3 centimeters on all sides has a mass of 45 grams. What is its density? Important Density: The density of liquid water = 1.0 g/cm3 Density = 45 grams / 9 cm3 Density = 1000 Kg / 20 m3 So, anything with a density smaller than 1.0 g/cm3 would float. Anything with a density larger than 1.0 g/cm3 would sink. Mass = 1000 Kg Density = 5 g/cm3 Volume = 10 m x 2 m x 1m = 20 m3 Density is measured using the same units for mass & volume; usually g/cm3 or kg/m3. Density = 50 Kg/m3

23. Lets think about this… Densityof object = 50 Kg/m3 Volume = 10 m x 2 m x 1m x100 x100 x100 Densityof water = 1 g/cm3 Mass = 1000 Kg Volume = 1000 cm x 200 cm x 100 cm x1000 The Units don’t match!!! Volume = 20,000,000 cm3 Mass = 1,000,000 g Density = 1,000,000 g / 20,000,000 cm3 Density = .05 g/cm3 We need to rethink this… IT FLOATS! How many cm are in a m? How many g are in a kg? So well, in fact, it could hold another 40,000 lbs before sinking.