Data and Graphs: Analyzing Earth and Space Data
Learn
Scientists collect vast amounts of data about Earth and space. To make sense of this information, they organize it into tables and display it using various types of graphs. This lesson teaches you to read, interpret, and draw conclusions from scientific data.
Types of Data in Earth Science
- Quantitative data: Numerical measurements (temperatures, distances, speeds)
- Qualitative data: Descriptive observations (colors, textures, classifications)
Reading Data Tables
Data tables organize information in rows and columns. When reading a table:
- Read the title to understand what data is presented
- Examine column headers to identify variables
- Check units of measurement
- Look for patterns or trends in the data
Types of Graphs Used in Earth Science
Line Graphs
Show how one variable changes in relation to another, often over time. Used for:
- Temperature changes with depth in Earth
- Seismic wave speeds through different layers
- Changes in atmospheric conditions over time
Bar Graphs
Compare quantities across different categories. Used for:
- Comparing sizes of planets
- Comparing thicknesses of Earth's layers
- Comparing mineral compositions
Pie Charts (Circle Graphs)
Show parts of a whole as percentages. Used for:
- Composition of Earth's atmosphere
- Distribution of Earth's water
- Elemental composition of Earth's crust
Scatter Plots
Show relationships between two variables. Used for:
- Relationship between distance from the Sun and planet temperature
- Correlation between earthquake magnitude and damage
Key Concept: Identifying Trends
When analyzing graphs, look for these patterns:
- Increasing trend: Values go up as you move right
- Decreasing trend: Values go down as you move right
- No trend: Values are scattered with no clear pattern
- Cyclical pattern: Values repeat in a regular pattern
Examples
Example 1: Reading a Data Table
Earth's Layers Data
| Layer | Thickness (km) | State | Temperature Range |
|---|---|---|---|
| Crust | 5-70 | Solid | 0-900 C |
| Mantle | 2,900 | Semi-solid | 900-4,000 C |
| Outer Core | 2,200 | Liquid | 4,000-5,000 C |
| Inner Core | 1,200 | Solid | 5,000-6,000 C |
Conclusions from the table:
- The mantle is the thickest layer
- Temperature increases with depth
- Only the outer core is liquid
Example 2: Interpreting a Line Graph
Scenario: A graph shows seismic wave velocity (km/s) on the y-axis and depth (km) on the x-axis.
Key observations:
- Velocity suddenly changes at about 35 km depth (crust-mantle boundary)
- A sharp decrease occurs at about 2,900 km (mantle-outer core boundary)
- Velocity increases again at about 5,100 km (outer core-inner core boundary)
Conclusion: Changes in wave velocity indicate boundaries between layers with different properties.
Example 3: Analyzing Planet Data
| Planet | Distance from Sun (AU) | Orbital Period (Earth years) | Surface Temp (C) |
|---|---|---|---|
| Mercury | 0.39 | 0.24 | 167 |
| Venus | 0.72 | 0.62 | 464 |
| Earth | 1.00 | 1.00 | 15 |
| Mars | 1.52 | 1.88 | -65 |
Pattern identified: As distance from the Sun increases, orbital period increases. Temperature generally decreases with distance (exception: Venus's greenhouse effect).
Practice
Use the data and your knowledge of Earth and space science to answer these questions.
Use the following table for questions 1-3:
| Depth (km) | P-wave Speed (km/s) | S-wave Speed (km/s) |
|---|---|---|
| 0 | 6.0 | 3.5 |
| 100 | 8.0 | 4.5 |
| 2,900 | 13.5 | 7.0 |
| 3,000 | 8.0 | 0 |
| 5,100 | 10.0 | 0 |
| 5,200 | 11.0 | 3.5 |
1. At what depth does the S-wave speed become zero?
- 100 km
- 2,900 km
- 3,000 km
- 5,200 km
2. Based on the S-wave data, which layer of Earth is liquid?
- Crust
- Mantle
- Outer core
- Inner core
3. What is the approximate thickness of the layer where S-waves cannot travel?
- 100 km
- 2,100 km
- 2,200 km
- 5,200 km
4. A pie chart shows that nitrogen makes up 78% of Earth's atmosphere and oxygen makes up 21%. What percentage is represented by all other gases combined?
- 0%
- 1%
- 10%
- 99%
5. A line graph shows temperature increasing as depth in Earth increases. This represents which type of trend?
- Decreasing trend
- Increasing trend
- No trend
- Cyclical pattern
6. Which type of graph would be BEST for comparing the diameters of the eight planets?
- Line graph
- Bar graph
- Pie chart
- Scatter plot
7. A scientist records earthquake data: magnitude 4.0 caused minor damage, magnitude 5.0 caused moderate damage, magnitude 6.0 caused severe damage. What type of relationship do these variables show?
- No relationship
- Inverse relationship
- Direct relationship
- Cyclical relationship
8. In a data table, the column header says "Distance (AU)." What does AU stand for?
- Actual Units
- Astronomical Unit
- Average Universe
- Atmospheric Unit
9. A scatter plot shows that as distance from the Sun increases, surface temperature decreases. One point (Venus) is much higher than expected. What might explain this?
- The data point is an error
- Venus has a thick atmosphere that traps heat
- Venus is actually closer to the Sun than shown
- Temperature and distance are not related
10. When creating a graph of Earth's layer thicknesses, which axis should show the layer names?
- The x-axis (horizontal)
- The y-axis (vertical)
- Either axis works equally well
- Neither - layer names should only be in the title
Check Your Understanding
Reflection Question 1: You are given data about seismic waves recorded at different distances from an earthquake. What type of graph would you create to display this data, and why?
Reflection Question 2: A graph shows that P-wave velocity suddenly drops at a certain depth. What does this tell scientists about the material at that depth?
Practice Problem Answers
1. C | 2. C | 3. C | 4. B | 5. B | 6. B | 7. C | 8. B | 9. B | 10. A
Next Steps
- Practice creating your own graphs from data tables
- Look for patterns and trends when you encounter scientific data
- Continue to the next lesson on CER Writing to learn how to use data as evidence in scientific arguments