1. Graph

2. Introduction:
Graphs are great because they communicate information visually.
For this reason, graphs are often used in newspapers, magazines and businesses around the world.
Data in tables can be displayed in a graph.
Common graph types include line graphs, bar graphs, and circle graphs / pie charts
Line graphs
Bar graphs
Circle graphs

3. Identifying variable
A variable is any factor that might affect the behavior of an experimental setup
Variable is the key ingredient when it comes to plotting data on a graph.
The independent variable is the factor that is changed or manipulated during the experiment
The dependent variable is the factor that observed and its depends on the independent variable.
4/8/2019

4. 1. Line Graphs
In Laboratory experiment, you will usually be controlling one variable and seeing how it affects another variable.
A line graph shows a relationship between two variables.
Line graphs
4/8/2019

5. Use the following steps to graph data.
Draw two perpendicular axes.
Identify the independent and the dependent variables.
The independent variable is plotted on the x-axis.
The dependent variable is plotted on the y-axis.
Give label each axis using the variable names.
Determine the range of data for each variable. Use the ranges to decide on a convenient scale for each axis. Mark and number the scales.
Plot each data point.
Draw a “best-fit” line through the points.
Write a title that clearly describes what the graph represents.

6. Example:
Draw a line graph of the data below from a cyclist in a long-distance race.
Table 1. Bicycle Race Data
Table 2. Bicycle Race Data
Time (hour)
Distance (km) 1 8 2 16 3 24 4 32 5 40
Time (s)
Velocity (m/s) 5 1 2 3 4
4/8/2019

7. Figure 1 This line graph shows the relationship between distance and time during a bicycle ride.
4/8/2019

8. Find a Slope
The slope of a straight line is the ratio of the vertical change, rise, to the horizontal change, run.
Example:
Find the slope of the graph in Figure 1.
Step 1 You know that the slope is the change in y divided by the change in x.
Step 2 Determine the data points you will be using For a straight line, choose the two sets of points that are the farthest apart.
Step 3 Find the change in y and x.
Step 4 Divide the change in y by the change in x.
The slope of the graph is 8 km/h
4/8/2019

9. Scatter plots (komplotan yg menyebar) of data may take many different shapes, suggesting different relationships.
4/8/2019

10. Interpreting Line Graphs
LINEAR relationship is a positive relationship between two variables in which they both increase or decrease in conjunction.
(Hubungan positif antara dua variabel dimana keduanya meningkat atau menurun secara bersama)
INVERSE relationship is a negative relationship between two variables in which one decreases when the other increases.
(Hubungan negatif antara dua variabel dimana yang satu menurun di saat yang lainnya meningkat)
4/8/2019

11. (hubungan dimana variabel bergantung pada kuadrat variabel lainnya)
Quadratic relationships exist when one variable depends on the square of another variable.
(hubungan dimana variabel bergantung pada kuadrat variabel lainnya)
The graph shown in the figure is a quadratic relationship.
4/8/2019

12. Exercise
A position-time graph for a bicycle is shown in the figure below.
What is the position of the bicycle at 1.00 min?
What is the position of the bicycle at 3.50 min?
What is the displacement of the bicycle
between the times 1.00 min and 5.00 min?
2. The position of an automobile is plotted as
a function of time in the accompanying figure.
What is the position of the car at 0.00 s?
What is the position of the automobile after 2.00 s has elapsed?
How far did the automobile travel between the times 1.00 s and 3.00 s?
4/8/2019

13. 2. Bar Graph
To compare data that does not change continously you might choose a bar graph.
A bar graph make an easy and quick data comparison
Bar graph can also be used to identify trends.
Bar graphs
4/8/2019

14. Example: A recycling center collects 4. 0 kg of aluminum on Monday, 1
Example: A recycling center collects 4.0 kg of aluminum on Monday, 1.0 kg on Wednesday, and 2.0 kg on Friday. Create a bar graph of this data.
Step 1 Select the x-axis and y-axis variables.The measured numbers (the masses of aluminum) should be placed on the y-axis.The variable divided into parts (collection days) is placed on the x-axis.
Step 2 Create a graph grid like you would for a line graph. Include labels and units.
Step 3 For each measured number, draw a vertical bar above the x-axis value up to the y-axis value. For the first data point, draw a vertical bar above Monday up to 4.0 kg.
4/8/2019

15. Figure 5. Bar graph of Aluminum Collected During Week
4/8/2019

16. 3. Circle Graph or pie chart
To display data as parts of a whole, you might use a circle graph.
A circle graph is a circle divided into sections that represent the relative size of each piece of data.
The entire circle represents 100%, half represents 50%, and so on.
Circle graphs
4/8/2019

17. Example: Air is made up of 78% nitrogen,21%, oxygen, and 1% other gases. Display the composition of air in a circle graph.
 Step 1 Divide each percent by 100 and Multiply by 360° to find the angle of each section in the circle.
Step 2 Use a compass to draw a circle and to mark the center of the circle. Draw a straight line from the center to the edge of the circle.
Step 3 Use a protractor and the angles you calculated to divide the circle into parts. Place the center of the protractor over the center of the circle and line the base of the protractor over the straight line.
4/8/2019

18. Figure 6. Circle graph of the gases in air
4/8/2019

19. Exercise 1. Draw a bar graph of the gases in
air: 78% nitrogen, 21% oxygen, 1% other gases.
2. Draw a circle graph to represent
the amount of aluminum collected during the week
shown in the bar graph from the example before.

20. Relation of temperature and Time
Objectives:
Student can make a graph relation temperature and time
Apparatus and Material
Laboratory thermometer
Tripod
Beaker glass
Gauze mat
Bunsen burner
Stopwatch
Measuring cylinder
Match

21. Procedure
Use a 100 mL measuring cylinder to measure out 100 mL of water and add it to the beaker.
Measure the temperature of water in beaker glass (write as temperature in time = 0 minutes)
Light your bunsen burner and adjust the collar to produce a blue flame.
Place bunsen burner under the beaker.
Record the temperature of water in every minutes until 10 minutes. Use stopwatch to measuring time.
After 10 minutes, turn off the bunsen burner. Wait a few minutes until your equipment has cooled before putting it away.
Data
Time (minutes)
Temperature (°C)

22. Analysis From your experiment, what is the independent variable?
What is the dependent variable?
Based on data result of your experiment, make a graph relation between temperature and time.
What would happen to the temperature of the water if you heated it for three minutes more?