Year 8 Science · Unit 2 · Lesson 04
Challenge Worksheet
Learning Goals
Evaluate the claim
Read the claim below carefully. Then answer each question in full sentences, using scientific ideas from the lesson.
Someone claims...
"The Bohr model of the atom should no longer be taught in schools because scientists now know it is not completely accurate. Students should only learn the quantum mechanical model, which correctly describes electron probability clouds rather than fixed orbits. Teaching an incorrect model gives students the wrong idea about how atoms work."
(a) What part of this claim is correct and supported by the science you have learned in this lesson?
(b) What is misleading about this claim? Use the idea of model usefulness in your answer.
(c) What evidence or argument would help you decide what level of atomic model is appropriate to teach at Year 8? Explain your reasoning.
1. A scientist says: "All models are wrong, but some models are useful." Explain what this statement means, using two different scientific models as examples in your answer. For each model, describe one way it is 'wrong' and one way it is still 'useful'.
2. When scientists replaced the Thomson model of the atom with the Rutherford model, was Thomson's model a failure? Explain your answer using what you know about how evidence causes models to change, and whether a replaced model can still have been valuable.
Wrap Up
In one sentence, what was the main idea of this lesson?