Studying Earth Science Chapter Two: The Science Toolbox • 2.1 Measurement • 2.2 Measuring Time and Temperature • 2.3 Systems and Variables • 2.4 Graphs 2.3 Systems and variables • • Graphs are a type of mathematical model. A graph is a picture that shows how two variables are related. 2.4 Graphs • A graph is a picture that shows how two variables are related. • Graphs explain more than just numbers alone, so they are often used to display data collected during an experiment. How far can you travel on 10 gallons of gas? 2.4 Graphs • Graphs are drawn with the independent variable on the horizontal or x-axis. • The dependent variable goes on the vertical or y-axis. • Types of graphs include line, bar, and pie graphs. 2.4 Parts of a graph • A graph is a picture of information. • Science information is usually organized in a table first. 2.4 How to make a line graph Step 1: Decide which is the dependent and independent variable. The dependent variable goes on the yaxis and the independent variable goes on the x-axis. 2.4 How to make a line graph Step 2: Make a scale for each axis by counting boxes to fit your largest value. Count by multiples of 1, 2, 5, or 10. 2.4 How to make a line graph • One box equals 0.42 hour per box. • Round 0.42 to 0.5. • This means every two boxes equals 1 hour. 2.4 How to make a line graph • • • • For the y-axis, the data range is $20 to $95. To more easily calculate the scale, choose $0 to $100 as the data range. Round $8.3 to $10. One box on the y-axis equals $10. 2.4 How to make a line graph Step 3: Plot each point by finding the x-value and drawing a line upward until you get to the right y-value. Draw a smooth curve that shows the pattern of the points. 2.4 How to make a line graph Step 4: Create a title for the graph Geology Connection Hydrogeologists and Their Tools • A hydrogeologist is like a detective and a doctor all in one. • These scientists are responsible for supplying and controlling groundwater. Activity Measurement Olympics • During the Measurement Olympics you and a partner will practice measurement and conversion skills.