📊 BAR GRAPH INSTRUCTIONS:
1) In your Science Notebook take notes on Bar Graphs.
2) After taking notes, complete Practice CAST Question below.
3) Then click Continue to complete the next section of notes.
4) Turn In: I will be stamping completed notes!
2) After taking notes, complete Practice CAST Question below.
3) Then click Continue to complete the next section of notes.
4) Turn In: I will be stamping completed notes!
Bar Graphs
Bar graphs are used to compare groups or categories. On the CAST, you often compare the control group to experimental groups and use evidence words.
Identify Variables & Groups
Bar Graph for Reaction Rate
Question: "How do different salt solutions affect the rate of a chemical reaction?"
- Independent variable: Type of solution (Control water, Salt A, Salt B, Salt C)
- Dependent variable: Reaction rate (bubbles per minute)
- Control group: Plain water (no added salt)
To read a bar graph:
- Look for the tallest bar (highest value).
- Compare bars to see which are similar in height.
- Use units in your sentences: “bubbles per minute.”
Reaction Rate with Different Salt Solutions
According to the data, some salts increase the reaction rate compared to the control.
10
18
16
12
Control
Salt A
Salt B
Salt C
Y-axis units: bubbles per minute. X-axis: type of solution.
Click a bar to see its value and practice an evidence sentence.
Notebook Task – Bar Graph Notes
- Redraw a smaller bar graph in your notebook with the same four bars and labels.
- Write answers to these sample CAST questions under your graph:
- Which treatment produced the highest reaction rate?
- Which two groups show the most similar results?
- How does the control group compare to the experimental groups?
- Start your answers with phrases like “According to the bar graph...” and “The evidence shows...”.
Practice – CAST-Style Bar Graph Questions
Use the bar graph values (Control: 10, Salt A: 18, Salt B: 16, Salt C: 12 bubbles per minute).
1. Which treatment produced the highest reaction rate?
2. A student writes: “According to the bar graph, the control group has a lower reaction rate
than all three salt solutions.”
Is this statement supported by the data?
Is this statement supported by the data?