Data Representation

Read and interpret graphs, tables, and charts on ACT Science

Data Representation (ACT Science)

What is ACT Science?

Not a test of science knowledge! It tests your ability to:

  • Read graphs and tables
  • Identify trends
  • Compare data
  • Draw conclusions

Types of Data Presentations

1. Graphs

  • Line graphs: Show trends over time
  • Bar graphs: Compare categories
  • Scatter plots: Show relationships

2. Tables

  • Organized rows and columns
  • Look at headers to understand what data represents

3. Diagrams

  • Show experimental setup
  • Illustrate processes

Reading Graphs

Step 1: Read the Labels

  • Title: What is being measured?
  • X-axis: Independent variable (what changes)
  • Y-axis: Dependent variable (what's measured)
  • Units: Pay attention! (meters, seconds, °C)

Step 2: Identify the Trend

  • Increasing? Decreasing? Constant?
  • Direct relationship? Inverse relationship?

Step 3: Find Specific Values

  • Trace from axis to data point
  • Interpolate (between points) or extrapolate (beyond graph)

Common Question Types

1. Direct lookup: "What was the temperature at 5 minutes?" 2. Trend identification: "As time increases, temperature..." 3. Comparison: "Which trial had the highest value?" 4. Prediction: "Based on the trend, what would happen at 10 minutes?"

ACT Tips

  • Skim passage first - know what you're looking for
  • Use the figures - answers are in the data, not your knowledge
  • Watch units! Convert if needed
  • Eliminate wrong answers - often obvious

📚 Practice Problems

1Problem 1easy

❓ Question:

When reading a line graph, what does the x-axis typically represent?

💡 Show Solution

Solution:

The x-axis (horizontal) typically shows the independent variable - the variable that is controlled or changes.

Examples:

  • Time (in experiments over time)
  • Temperature (when testing at different temps)
  • Distance (when measuring across space)

Answer: The independent variable (what is being changed/controlled)

ACT Tip: Always read axis labels carefully!

2Problem 2medium

❓ Question:

A graph shows temperature increasing from 0°C to 100°C while pressure increases from 1 atm to 5 atm. What is the relationship?

💡 Show Solution

Solution:

Both variables increase together.

This is a direct (positive) relationship:

  • As temperature ↑, pressure ↑
  • As temperature ↓, pressure ↓

Inverse relationship would be:

  • As one ↑, the other ↓

Answer: Direct (positive) relationship

ACT Tip: Identify if both increase together (direct) or move opposite (inverse)

3Problem 3hard

❓ Question:

A table shows data at 10°C, 20°C, and 30°C. A question asks about 25°C. What should you do?

💡 Show Solution

Solution:

25°C is between 20°C and 30°C but not in the table.

This requires interpolation (estimating between known values).

Strategy:

  1. Find the two closest values (20°C and 30°C)
  2. Estimate the midpoint between their results
  3. 25°C is halfway between, so pick middle value

Answer: Interpolate between the two closest data points

ACT Tip: Interpolate = between points; Extrapolate = beyond the data

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