The Metric System Unit 0 Lesson 6 UNITS OF MEASUREMENT Scientists worldwide use a single system of measurement: System International dUnites (International System of Measurements) or SI. Its main units of measurement are: o Length: o Volume: o Mass: Meter (m) Liter (L) Kilogram (kg) PREFIXES AND UNITS Prefixes indicate multiples or fractions of units of measurement. Units give specific meaning to numbers. Prefix Meaning Kilo 1,000 Hecto 100 Used together, prefixes and units provide information about how much and what was measured. Deka
10 Deci 0.1 Centi 0.01 Milli 0.001 It is common to refer to both the prefix and the unit as units or set of units. CONVERSION It is often necessary to convert one set of units to another. Prefix Meaning Kilo 1,000 The conversion is done by finding the number of decimal places traversed or jumped when moving from one prefix to another. Hecto 100
Deka 10 Deci 0.1 Centi 0.01 Milli 0.001 CONVERSION EXAMPLE 1 Example: Convert 225 milliliters to hectoliters. How many jumps is it from milli to hecto? Kilo hecto deka (main unit) deci centi milli There are 5 jumps to the left. Move the decimal point 5 places to the left, filling the empty spaces after the decimal point with zeroes. 225 milliliters = .00225 hectoliters Prefix Meaning Kilo 1,000 Hecto 100
Deka 10 Deci 0.1 Centi 0.01 Milli 0.001 CONVERSION EXAMPLE 2 Example: 15.78 kilograms = 1,578,000 centigrams To convert 15.78 kilograms to centigrams, move the decimal point 5 places to the right, filling in the extra space with zeroes. o In this example the prefix is converted from what to what? o And the unit is? Prefix Meaning Kilo 1,000 Hecto 100 Deka
10 Deci 0.1 Centi 0.01 Milli 0.001 GRAPHING Graphing is used to display data that is collected during a controlled experiment. Cabbage Growth vs. Lettuce Growth Cabbage Lettuce 90 77 80 A graph must contain 5 major parts: Title Independent variable (X axis) Dependent variable (Y axis) Scales for each variable Legend 61
Total Growth (mm) 1. 2. 3. 4. 5. 70 60 49 50 41 40 39 32 3024 20 10 0 Week 1 Week 2 Week 3 Time in Weeks Week 4 PARTS OF A GRAPH o The title should clearly depict what the graph is about.
Growth vs. Lettuce Growth Cabbage Lettuce 90 77 80 70 61 Total Growth (mm) o The independent variable is the variable which is controlled or predictable in an experiment. It is placed on the horizontal X axis. TitleCabbage 60 49 50 41 40 39 32 3024 20 o The dependent variable is what changes in response to the independent variable. It is placed on the vertical Y axis.
10 0 Week 1 Week 2 Week 3 Time in Weeks Week 4 PARTS OF A GRAPH o The legend is the description of the data. For example, if you are using a line graph and have multiple lines of different colors, the legend should explain what each color represents. Cabbage Growth vs. Lettuce Growth Cabbage Legend Lettuce 90 77 80 70 61 Total Growth (mm) o In order to know where to plot data
points, scales must be used on both axes. Scales typically start at 0 and increase based on set intervals like 2, 5, 10, 20, etc. The scale will be dictated by your data. 60 49 50 41 40 39 32 3024 20 10 0 Week 1 Week 2 Week 3 Time in Weeks Scales Week 4