Check the row that could prove you wrong
- The idea
- Predict
- See it
- Why
- Check
The idea
“My explanation fits these rows, so it explains the data.”
Rows that agree with your idea feel like proof. They often fit other ideas just as well.
The short version
The mistake: My explanation fits these rows, so it explains the data.
What's actually true: An explanation has to fit every row. One row it can't explain is enough to rule it out.
- A claim makes a prediction for every row. Plants A to D fit "acid makes blue," but they also fit "acid plus aluminum makes blue," so they can't tell the two apart.
- Acidic soil makes aluminum soluble so roots can absorb it. Aluminum ions bind the flower pigment and turn it blue.
- Flower color here is a phenotype shaped by two environmental factors together.
On the exam: Look for the row that could break your explanation. If one row disagrees, it's out.