1. Measurements in Science Chapter 1

2. Accuracy and Precision Accuracy: A description of how close a measurement is to the true value of the quantity measured. Precision: The exactness of a measurement.

3. Qualitative vs. Quantitative Data Qualitative Data: data that cannot be measured on a numerical scale Quantitative Data: data measured or identified on a numerical scale. Examples (qualitative or quantitative?): “The temperature in this room is 23 degrees Celsius." “The temperature in this room is 23 degrees Celsius." “This room is warmer than it is outside". “This room is warmer than it is outside". “The tree is taller than the building." “The tree is taller than the building." "The tree is 30 feet tall." "The tree is 30 feet tall."

4. Metric Conversions The SI System was created to make a universal system of measurement in science. The SI System was created to make a universal system of measurement in science. The SI system is based largely on the metric system. It is based on multiples of 10 which makes conversions simple. Base Quantity NameSymbol lengthmeterm masskilogramkg timeseconds electric current ampereA temperatureKelvinK amount of substance amount of substancemolemol luminous intensity candelacd SI Base Units

5. KILO 1000 Units HECTO 100 Units DEKA 10 Units DECI 0.1 Unit CENTI 0.01 Unit MILLI 0.001 Unit Meters Liters Grams Ladder Method How do you use the “ladder” method? 1 st – Determine your starting point. 2 nd – Count the “jumps” to your ending point. 3 rd – Move the decimal the same number of jumps in the same direction. 4 km = _________ m 1 2 3 How many jumps does it take? Starting Point Ending Point 4. 1 __. 2 3 = 4000 m

6. Try these conversions using the ladder method. 1000 mg = _______ g 1 L = _______ mL160 cm = _______ mm 14 km = _______ m109 g = _______ kg 250 m = _______ km Conversion Practice Compare using, or =. 56 cm 6 m 7 g 698 mg

7. Graphing Numerical data collected from an experiment is arranged into a data table so that its information can be read quickly. Example: The following hair colors were found among three classes of students: Example: The following hair colors were found among three classes of students: Class 1: brown = 20 black = 1 blonde = 4 Class 2: brown = 18 black = 0 blonde = 6 Class 3: brown = 15 black = 4 blonde= 15

8. Graphing A line graph is best for displaying that change. A line graph usually consists of two axes upon which the different variables of the experiment are graphed: A line graph usually consists of two axes upon which the different variables of the experiment are graphed: The independent variable is always placed on the X axis. The dependent variable is always placed on the Y axis.

9. Graphing A bar graph is useful when you want to compare data for several individual items or events.

10. Graphing A pie chart or circle graph is ideal for displaying data that are parts of a whole.