Reading the Data
Learning Objectives
Students will be able to:
- Create a line graph from CO2 data
- Interpret what a graph shows about air quality changes
- Identify patterns and trends in the data
- Explain what caused changes in CO2 levels
The Big Question
"What story does our data tell about our classroom air?"
Numbers in a table are useful, but graphs help us SEE the story in the data!
Tables show:
- Exact numbers
- Organized information
- All the details
Graphs show:
- Patterns and trends
- Changes over time
- The "big picture"
Line Graph
Best for: Showing how something changes over TIME
Example: CO2 levels throughout the day
Points connected by lines show the trend!
Bar Graph
Best for: Comparing different things or places
Example: CO2 in different rooms
Bars make it easy to compare!
Step-by-Step Instructions
Step 1: Set Up Your Graph
- Draw two lines that meet in a corner (the axes)
- The bottom line (x-axis) = TIME
- The side line (y-axis) = CO2 LEVEL (ppm)
Step 2: Label Your Axes
- On the bottom, write your time points (8am, 9am, 10am, etc.)
- On the side, write CO2 levels (400, 600, 800, 1000, 1200, etc.)
- Add axis labels: "Time" and "CO2 (ppm)"
Step 3: Plot Your Points
- For each measurement, find the time on the bottom
- Go up to the correct CO2 level
- Make a dot at that spot
Step 4: Connect the Dots
- Draw lines connecting each point to the next
- This shows how CO2 changed over time!
Step 5: Add a Title
Give your graph a title like: "Classroom CO2 Levels - [Date]"
What Patterns Do You See?
Look for:
- Peaks (high points): When was CO2 highest? What was happening?
- Valleys (low points): When was CO2 lowest? Why?
- Upward slopes: CO2 increasing - people came in? Windows closed?
- Downward slopes: CO2 decreasing - windows opened? Room emptied?
Example Patterns
| Pattern on Graph | What It Might Mean |
|---|---|
| Line goes UP quickly | Many people arrived, windows closed |
| Line goes DOWN | Windows opened, people left, or room aired out |
| Line stays FLAT (high) | CO2 built up and stayed high - needs more fresh air! |
| Line stays FLAT (low) | Good ventilation keeping CO2 low |
| Big drop during lunch | Room was empty - CO2 had time to clear out |
Annotate Your Graph!
Scientists add notes to their graphs to explain what was happening. Add labels to your graph showing:
- "Windows opened" at the point where that happened
- "Class left for lunch" at the drop
- "All students arrived" at the peak
- Any other important events!
Discuss as a class:
- What was the highest CO2 reading? Was it above 1000 ppm (the "stuffy" level)?
- What was the lowest CO2 reading? When did it happen?
- How much did CO2 change from lowest to highest?
- What could we do to keep CO2 levels lower throughout the day?
- Does our classroom have good ventilation? How do you know from the data?
Include in your notebook:
- Your completed line graph with title and labels
- Annotations explaining what was happening at key points
- Answers to these questions:
- What pattern(s) did you notice in the data?
- What caused CO2 to go up?
- What caused CO2 to go down?
- What recommendation would you make to improve our air quality?
Key Takeaways
- Graphs help us see patterns in data that tables can't show
- Line graphs are great for showing changes over time
- Peaks and valleys in the graph tell a story about what happened
- Adding notes to graphs helps explain the patterns
- Data can help us make decisions about improving air quality
Graph
A picture that shows data in a way that's easy to understand.
Axis
The lines on a graph that show what is being measured (x-axis and y-axis).
Trend
The general direction data is going (up, down, or staying the same).
Annotate
To add notes or labels to explain something.