Understanding Graphing and the Metric System: Visualizing Data and Measurements

1. Unit 1 Graphing, Metric System and Measurement

2. How can we look at our data? • Use a graph • A graph is a visual display of information or data

3. Circle Graphs or Pie Charts • Used to show how a fixed quantity is broken down into parts. • The circle represents the total and the slices represent the parts.

4. Bar Graphs • Useful for comparing information collected by counting.

5. Line Graphs • Used to show trends, or how data changes over time.

6. Parts of a Graph • Title: Tells what the graph is about • Independent Variable: The variable controlled by the experimenter (x-axis) • Dependent Variable: The variable affected by the independent variable (y-axis)

7. Parts of a Graph • Scale: The numbers used on the axis (should include all data) • Legend: Describes data being graphed

8. Parts of a Graph Title Dependent Variable Scales (Numbers) Independent Variable Legend

9. Metric System

10. Metric System • Bill Nye explains the metric system!

11. Metric System • The metric system is a standard system of measurement. • We use prefixes with base units

12. Prefixes

13. Problem • We need to measure the size of the room. • What is the base unit? • For length, we use meters. • The room is 10m long.

14. Problem • What if we need to measure a longer distance, like from home to school? • You live approximately 10 miles from school • 10 miles = 16100m • That’s a big number. By changing the prefix and moving the decimal, we can make it more manageable. • 16100m = 16.1km

15. Whiteboard Practice • Convert 2.53g to kg • Convert 0.0741L to dL • Convert 125.2mm to m • Convert 561kL to mL • Convert 334.5cg to dag • Convert 0.425 hm to dm

16. Measurement

17. Measurement • Metric System - System of measurement used by scientists • Also known as the International System of Units, abbreviated SI • Based on the number 10

18. Length • Length is the distance between two points • base unit is the meter (abbreviated m) • measured with a meter stick or a metric ruler

19. Measuring Length • Start the measurement at the 0cm mark on the ruler or meter stick • Read the length of the object to the whole centimeter, plus 2 decimal places (estimate the last one)

20. Measurement Practice • Measure the length of the index card • Measure the length of the pencil • Measure the length of the paper clip • Record your group’s results on the board at the front of the room. • Measure 5.0mL of water in the graduated cylinder and show Mrs. A.

21. Temperature • Temperature is a measurement of how hot or cold something is • Unit is ºC • Water freezes at 0ºC • Water boils at 100ºC • The celsius scale is divided into 100 equal divisions • Read thermometers to the nearest degree or half degree

22. Volume • Volume is the amount of space occupied by an object • base unit is the liter (abbreviated L)

23. Measuring Volume • Volumes of many solid objects may be calculated by measuring the length, width, and height of the object, then multiplying the numbers together: V = L x W x H

24. Calculating Volume V = L x W x H V = 4cm x 3cm x 12 cm = 144 cm3

25. Measuring Volume • Liquid volumes should be measured with a graduated cylinder (in mL) • When reading a graduated cylinder, look at the graduated cylinder at eye level • Read the bottom of the meniscus, the curve of the liquid on the cylinder • Read to the nearest unit or half unit

26. Measuring Volume • Volumes of irregular solid objects may be determined by the displacement method • Put some water in a graduated cylinder and record the volume • Add the object to the graduated cylinder • Record the new volume • The difference between the new volume and the original volume is the volume of the object

27. Mass • Mass is the amount of matter in an object • standard unit is the kilogram (abbreviated kg) • Our balances measure mass in grams (g)

28. Measuring Mass • Measure the mass of a solid using a balance • Our balances are digital • Use a weigh “boat” to hold the solid on the pan of the balance

29. Measuring Mass • Digital balance • Make sure the balance reads 0.0g • If not, press the “Zero”button • Measure the mass of the boat and record it • Add the solid to the boat • Measure the mass of the boat and the solid • To find the mass of the solid, subtract the mass of the boat from the mass of the boat and the solid

30. Measuring Mass • Measure the mass of a liquid using a balance and a graduated cylinder (GC) • First mass the empty GC • Add the liquid to the GC • Mass the liquid and the GC together • To get the mass of the liquid, take the mass of the liquid and GC and subtract the mass of the GC.

31. Measurement Lab • 9 Stations • Work in assigned groups • Rotate through the stations in order, going to station 1 after you finish station 9 • Be sure to clean up each station and put everything back the way you found it before moving to the next one

32. Density • Density is the mass per unit volume of a material • Density may be used to identify a material

33. Density • Density is calculated using this formula • Density = mass volume • Units are usually g/cm3 • This formula is on your reference table