Nature of Science

1. Nature of Science Metric System-International System of Units (SI)

2. Learning Targets: Use appropriate tools and equipment for measuring Use the metric system for measuring Use the “ladder method” and dimensional analysis to convert values between metric and English units

3. Merci Beaucoup!!!

4. Standardized system of measurement used by all scientists worldwide. • Based on units of 10 • Similar to our monetary system: 10 cents = dime 100 cents = dollar 10 dimes = dollar The Metric System

5. Measurements are easily understood by all scientists • Measurements are easier to convert than the English system Why use the SI System? In the U.S. we use the English or Standard System, most of the rest of the world uses the Metric or SI System. Scientists use the SI System worldwide because: The SI (International System of Units) system is the form of measurement typically used by scientists.

6. 12 inches in a foot • 3 feet in a yard • 5,280 feet in a mile • 16 ounces in a pound • 4 quarts to a gallon In the SI System you only have to remember one number - 10 and a few basic units In the English system you have to remember so many units numbers . . .

7. Length: measures distance between objects Volume: measures the amount of space something takes up Mass: measures the amount of matter in an object Temperature: measures molecular movement in an object Basic Types of Measurement

8. Measurement System Comparisons All Measurement systems have standards. Standards are exact quantities that everyone agrees to use as a basis of comparison.

9. 1 Liter 1 Gram 1 Meter

10. A Canook’s Rhyme Thirty's warm, twenty's nice; ten's cold, zero's ice

11. Weight vs. Mass Measure of the force of gravity on an object Measure of amount of matter in an object NOT affected by gravity

12. Weight vs. Mass • Weight and Mass are related, but NOT the same. • Weight can change depending on location • Mass is constant regardless of location • The greater the mass, the larger the pull of gravity. • The larger the pull of gravity, the greater the weight

13. The Base Unit is the determined by the type of measurement being made. (mass, volume, or length) The same prefixes are used regardless of the the measurement type being made length, mass, or volume. Metric System Prefixes

14. Metric Prefixes Kilo Hecto Increase to Basic Unit Deca Basic Unit (g,m,L) Deci Centi Decrease to Basic Unit Milli

15. µ- micro- one millionth ex. Micrometer or micron • n- nano- one billionth

16. Abbrev. Word Meaning mm millimeter one thousandth meter cg kL cm mL mg km kg

17. Abbrev. Word Meaning mm millimeter .001 meter (thousandth) cg centigram .01 gram (hundredth) kL kiloliter 1000 liters cm centimeter .01 meter (hundredth) mL milliliter .001 meter (thousandth) mg milligram .001 gram (thousandth) km kilometer 1000 meters kg kilogram 1000 grams

18. “Ladder Method” • Used for metric to metric conversions • Conversions are done by moving the decimal point. • Larger to smaller unit: Move decimal point to the right • Smaller to larger unit: Move decimal point to the left

20. The Metric System is used for everyday life in most countries except the United States, Liberia and Myanmar

21. Dimensional Analysis/Factor Label Method Method we will use to convert English – Metric units. When does this skill come in handy?

22. Dimensional Analysis • Determine the equality relationship between units ex. 2.54 cm = 1 inch • Write the relationship between the units as a fraction with the desired unit in the numerator (top) and the unit you have in the denominator (down). This is the conversion factor . 2. 54 cm Numerator 1 inch Denominator • Multiply the value you have by the conversion factor - it’s like multiplying by one. 10 inches x 2.54 cm 1 inch • Cancel out the units , multiply, solve 10 inches x 2.54 cm = 25.40 cm 1 inch

23. Choosing Conversion Factors • How many feet are in 144 inches? • Determine the relation between feet and inches 12 inches OR 1 foot___ 1 foot 12 inches • Choose the conversion factor with the desired unit in the numerator

24. Choosing Conversion Factors • How many feet are in 144 inches? • Determine the relation between feet and inches 12 inches OR 1 foot 1 foot 12 inches • Choose the conversion factor with the desired unit in the numerator

25. Practice: Choose the appropriate conversion factor. Inches to feet Minutes to hours Meters to centimeters

26. Practice: Choose the appropriate conversion factor. Inches to feet Minutes to hours Meters to centimeters

27. Example #1 • 36 eggs = ? Dozen • Determine equality 12 eggs = 1 dozen • Determine Conversion factor 12 eggs or 1 dozen 1 dozen 12 eggs

28. Example #1 • 36 eggs = ? Dozen • Determine equality 12 eggs = 1 dozen • Determine Conversion factor 12 eggs or 1 dozen 1 dozen 12 eggs

29. Example #1 • 36 eggs = ? Dozen • Conversion factor: 1 dozen 12 eggs • 36 eggs x 1 dozen = 36 x 1 dozen = 3 dozen 12 eggs 12

30. Example #2 • 10 cm = ___?___ inches • Choose conversion factor: 2.54 cm or 1 inch__ 1 inch 2.54 cm Although these are both equivalent, choose the one with the desired unit in the numerator (top)

31. Example #2 • 10 cm x 1 inch__ = _________ 2.54 cm 10 cm x 1 inch__ = 10 x 1 inch = 3.93 in 2.54 cm 2.54

32. Convert 8 yards to feet… • Determine the equality relationship between units • Make a decision: What conversion factor will you use? Set up the problem: Multiply the measurement by the conversion factor. Solve the problem: Perform the multiplication

33. Things to Remember • All measurements need a number and a unit! • Basic units of Measurement (meter, liter, gram) • Metric prefixes and values • How to convert units

34. Measurement Review • Measurements need a number and a unit! • Basic units of Measurement(meter, liter, gram) and prefixes • How to convert metric units • Be able to make basic measurements of volume, length, and mass • Definition of density and how to figure it out. • Vocabulary words

35. Metric Measurement:Length • Length is the distance between two points. • Does not matter if it is width, height, depth, etc. All are length measurements. • The basic unit of length in the SI System is the meter. • The meter is about the length of the English yard (3 feet). • Area is a variation of a length measurement. • Area is length x width. • Expressed in units2 (m2, cm2, mm2 etc.)

36. Metric Measurement:Mass • Mass is a measurement of the amount of matter in an object. • Basic unit of mass is the gram. There are 454 grams in one pound. • Weight and mass are related, but NOT the same. • Weight is the pull of gravity on an object • The greater the mass, the larger the pull of gravity.

37. Metric Measurement:Volume • Volume is a measurement of the amount of space something takes up. • The basic unit used for volume is the liter. This unit is used for the volumes of liquids. • Volumes of solids are figured using this formula: (L)ength x (W)idth x (H)eight cm x cm x cm = cm3 • Objects without a definite length, width or height (a rock for example), can use water displacement to determine volume.NOTE:1 ml = 1 cm3

38. Metric Measurement:Temperature • Temperature is a measure of the kinetic energy of the atoms in an object. • Temperature is measured with a thermometer and measured in Celsius or Kelvin. • Celsius ranges from 0 (freezing) to 100 (boiling). • The Kelvin scale begins at absolute zero, or 0 K. At 0 Kelvin no more heat can be removed from an object. • To convert to Kelvin you add 273 degrees to the Celsius reading. • Freezing in Kelvin is 273 K, boiling is 373 K.

39. Density is how much matter is in something (mass),compared to the amount of space it takes up (volume). Which is heavier . . . A kilogram of feathers or a kilogram of lead? They are both one kilogram so they weight the same, but it takes more feathers than lead to equal one kilogram! The formula for density is: Mass (grams) divided by Volume (cm3) So the unit for density isg / cm3 • Every substance has a density, and that density always remains the same. • Density can be used to figure out what an unknown substance is. • The density of water is 1 g / cm3 Which one takes up more space (volume)? We say the lead is more dense than the feathers.