GRAPHING BASICS Data Management Graphing 1 Data Management

GRAPHING BASICS Data Management & Graphing 1

Data Management n Experimental Data ¡ ¡ 2 Types n Quantitative data – Data gathered in the form of numerical measurements n Qualitative data – Data gathered by making observations using your senses Data collected - organized in a data table. 2

Data Table Format n Data Table Format: ¡ ¡ ¡ Label your independent variable and unit in first/leftmost column Label your dependent variable and unit in the next/right column REVIEW: n Independent Variable ¡ n The thing that is changed in experiment Dependent Variable ¡ The thing that is measured in the experiment (data gathered) 3

Why Graph? n n n Graphs are an effective way to visually display the information or data collected in an experiment. Graphs can show a trend in information or data collected. The shape of the trend will often have a math formula and relationship associated with it. This can help you predict data if you don’t want to gather it with an experiment 4

Line Graph n n n Used to show changes over time or rates of change in something. Used when you can make a sequential scale with the data being collected. Example: ¡ Change in average speed compared to the distance traveled. 5

Graph Titles n n A title for a graph should describe what the experiment was comparing For line graphs: ¡ ¡ Titles should list the dependent variable vs. the independent variable This allows you to see the slope calculation in the title n n Temperature vs. Time All titles are placed at the TOP of the graph 6

Bar & Line Graphs n Line graphs are constructed on a set of axes ¡ ¡ n X axis runs horizontal ( →) Y axis runs vertical (↑) Y-axis These axes must be labeled properly ¡ ¡ The x-axis should be labeled with independent variable and unit The y-axis should be labeled with dependent variable and unit X-axis 7

Creating Line & Bar Graphs Line graphs must: • use paper with grid lines (i. e. graph paper) if not created on a computer • use even graduations or scale with even increasing or decreasing increments along axis - to determine scale for x and y axis: divide range of data by the number of lines on the axis. 8 (data range is highest value – lowest value)

Calculating the Scale Example n n n Speed (m/s) Water Temperature (°C) Left hand column = 17 25 independent variable. 14 28 Data range = subtract 11 31 high data point from 8 34 low data point. 5 37 ¡ Data range: 17 Divide the range by the number of lines -5=12 12 = 0. 54 = 1. 0 Count the number of 22 lines on the axis you Round up to a number that is will be putting the easy to count by: scale on. 0. 1, 0. 2, 0. 5, 1. 0, 2. 0, 5. 0, 10. 0 For example: 22 9

Line Graph Rules Line graphs must: • Maximize the size of the graph (use most of the graph paper!) • use a smooth line or curve to connect the data points NEVER CONNECT THE DOTS • your teacher will tell if you should use a smooth curve or a straight line 10

For the following, identify the parts of the experiment: Practice Laura was watching a special on HGTV (Home and Garden TV) that was on the effects of different amounts of fertilizer on plant growth. It said that the more fertilizer that could be added, the more the plants would grow. She decided to experiment to see if it was true. She went to her garden and removed 6 tulip bulbs. She placed them in 6 identical pots, watered them with the same amount of water. She decided to add the following amounts of fertilizer to the plants: Plant A (0 g); Plant B (3 g); Plant C (6 g); Plant D (9 g). She went back after 10 days and measured the height of each plant. She measured the plants as follows: Plant A (5 cm), Plant B (7 cm), Plant C (9 cm), Plant D (11 cm). What is the hypothesis? If I add more fertilizer, the plants will grow more. What is the Control? Plant A What are the Constants? Pots, tulips, water, measured after same amt. of time What is the Independent Variable? What is the Dependent Variable? Amount of fertilizer Plant growth 11

Practice Scenario (continued) Fill in the data table below. Consult the scenario to find the proper numbers to put in the table as well. A B C D 0 3 6 9 5 7 9 11 12

Practice Scenario (continued) Now, using your answers from the earlier scenario, correctly title and label the axes below: A 0 5 B 3 7 C 6 9 D 9 11 13