Measurements and Units

1. Measurements and Units

2. Long Ago… Parts of the human body were often used to measure. The length of the king’s foot or the distance from the tip of his nose to his fingertips were both common units of measurement.

3. Problems • It would often change as soon as a new king was crowned • It was different from country to country Which is a basketful?

4. SI system 1790 • (metric system) – a standard unit of measurement All scientists everywhere can share and replicate the same data. Now used in nearly every country in the world except the United States.

5. Metric System throughout the World Gray – countries that only use the metric system Red – countries that don’t use the metric system (U.S., Liberia, Burma)

6. What is the Metric System? • There is only onebase unit for each thing measured Length = meter Mass = gram Volume = liter

7. Measuring Length Whether you are measuring the length of your finger or the length of the Nile River, you always use meter.

8. Measuring Mass or Weight Whether you are measuring the mass of a nickel or the mass of a car, you always use gram.

9. Measuring Volume Whether you are measuring the volume of a glass of water or the volume of a swimming pool, you always use liter.

10. Compare the difference 13 words 3 words

11. How big are they? • METER – a little longer than a yard (1.1 yards) • LITER – a little larger than a quart (1.06 quarts) • GRAM – about the mass of a paper clip

12. What about measuring really big or really small things? • In the English system, we would use inches • But in the metric system, since the meter measures everything, it is broken up into smaller units and prefixes are added to the word “meter.”

13. Measured in multiples of 10 • Prefix - represent the multiples of 10 decimeter “deci” = .1 or 1/10 centimeter “cent” = .01 or 1/100

14. 6 common prefixes:

15. Kilo- • Symbol = k • Number = 1000 kilometer kiloliter kilogram 1000 meters 1000 liters 1000 grams

16. Hecto- • Symbol = h • Number = 100 hectometer hectoliter hectogram 100 meters 100 liters 100 grams

17. Deka- • Symbol = da • Number = 10 dekameterdekaliterdekagram 10 meters 10 liters 10 grams

18. Meter, Liter, Gram • Symbol = m, l, g • Number = 1 meter liter gram length volume mass or weight

19. Putting the 2 symbols together Kilo = k meter = m • Kilometer = km • Hectogram = hg • Kiloliter = kl

20. Deci- • Symbol = d • Number = .1 (tenth) decimeter deciliter decigram .1 meter .1 liter .1 gram

21. Centi- • Symbol = c • Number = .01 (hundreth) centimeter centiliter centigram .01 meter .01 liter .01 gram

22. Milli- • Symbol = m • Number = .001 (thousanth) millimeter milliliter milligram .001 meter .001 liter .001 gram

23. 6 common prefixes:

24. Practice • If I give you the symbol, you give me the prefix h = m = c = k = d = da =

25. Practice • If I give you the prefix, you give me the number kilo = hecto = deka = centi = milli = deci =

26. Practice • If I give you the symbols, you give me the word mg = cl = hm = dg= dal = km =

27. Practice • If I give you the prefix, you give me the symbol deka = kilo = milli = deci = hecto = centi =

28. Practice • What is the base unit for length? • What is the base unit for mass or weight? • What is the base unit for volume?

29. Even if you live in the U.S., you're using the metric system—probably without realizing it. Your home computer might have several megabytes of memory and a few gigabytes of storage. Mega- and giga- are prefixes used in the metric system. Mega- stands for "one million," so a megabyte is a million bytes. Giga- stands for "one billion." If computing continues at the rate it's been going, we may soon be talking about petabytes—one million billion bytes.

31. About 15 years ago, Congress passed a law saying that all consumer products had to include both English and metric measurements