Standards of the past

Transcription

1 Metric Prefixes

2 Measurement Must have a standard. A standard is an exact quantity people agree to use for comparison. A standard means two people using the same object should get close to the same results.

3 Standards of the past People used to use parts of their body to determine the length of something. The standard would be a part of the king s anatomy. The standard yard was the distance from the king s nose to his outstretched arm

4 People would use their feet to This is how the term foot came about. Today the standard foot in the English system is 12 inches = 1 foot measure distance

5 The English system is very confusing because it has so many Example: Ounces, pounds, gallons, inches, feet, yards different values

6 America is the only country that still uses the old English system

7 Scientists give the English system the thumbs down Scientists needed an exact and uniform system of weights and measurements

8 How did the metric system come During the18th century scientists measured the distance from the earth s equator to its North Pole and divided it into ten million parts. This is how they came up with the length of the standard meter. about?

9 The Meter The standard for the meter is kept in a safe in France. The meter stick is a replica of that standard A meter is made up of 100 centimeters and 1000 millimeters

10 How the liter came about Scientists needed a way to measure liquids so they took 10 cm and multiplied it by its length x width x height to come up with a standard for measuring volume The liter is the size of 10 cm(3) 10cm x 10 cm x 10 cm Length x Width x Height = Volume The liter is used to measure liquids

11 How the Gram came about Scientists needed a standard to measure mass. Mass is the amount of matter in an object They decided to take one cubic centimeter of water and call it a gram

12 The time standard During the 15 th century a scientist named Galileo set the standard of time known as the second

13 The Mistake Two different groups of scientists were working on the calculations to send a probe to Mars. The American team did their calculations in the English standard and the other team did it in the metric system (OOPS!) MARS

14 This made scientists very upset. It cost the space program 125 million dollars It cost the scientists their time

15 Metric chart Kilo means thousand (1000) Hecto means hundred (100) Deca means ten (10) Deci means one-tenth (1/10) Centi means one-hundredth (1/100) Milli means one-thousandth (1/1000)

16 Base Units The Meter- Base unit and Measures length Length is the distance between two points The Liter Base unit and Measures Volume Volume is how much space a liquid takes up The Gram- Base Unit and Measures mass Mass is how much matter is in an object The Base unit for Temperature is degrees Celsius The Base unit for Time is the second

17 Volume 1 Cubic Centimeter (1cc) is equal to 1 ml Graduated Cylinder is used to measure volume. You read the value at the meniscus

18 Metric Conversion Chart

19 Metric Conversion chart Use KHDBDCM How to use the metric chart Rewrite the problem Check for the decimal (if no decimal, put at end) Where do we start? Put pencil their Were do we go to? # of hops and direction Do the same with decimals

20 Dimensional Analysis A better way for metric conversions. Very important in Chemistry and Physics! We will go over this later!

21 How the metric system works kilo hecto deca UNIT deci centi milli (meter, gram or liter) 100cm = m 100cm = 1.0 m 6.9mm = cm 6.9mm =.69 cm