Year 8 Science · Unit 2 · Lesson 09

History of the Atomic Model

Challenge Worksheet

Name

Date

Class

Learning Goals

Identify and correct scientific misconceptions about the history of atomic models.
Evaluate what the history of the atomic model reveals about how science actually works.
Distinguish between "disproving" a model and building upon it with better evidence.

Go Deeper

Find the mistake

A student wrote this answer

"Dalton invented the atom in 1803. Before Dalton, people didn't know atoms existed. When Rutherford did his experiment, he proved that the plum pudding model was completely wrong, so Thomson's work was wasted. The Bohr model is the correct model of the atom and has never needed changing."

1. Identify at least three mistakes in the student's answer. List each one clearly.

Challenge 3 marks

2. Rewrite the student's answer correctly, fixing all the errors you identified.

Challenge 3 marks

3. Choose one of the misconceptions from the student's answer and explain why it is an easy mistake to make. What idea might lead a student to think this?

Challenge 2 marks

Show What You Know

1. The atomic model changed four times between 1803 and 1913. Each change was driven by new experimental evidence. What does this pattern tell us about how science actually works, not just about what atoms look like, but about the nature of scientific knowledge itself? Use specific examples from the history of the atomic model in your answer.

Challenge 4 marks

2. When Rutherford's gold foil results arrived, they were completely unexpected. Rutherford reportedly said it was like firing artillery shells at tissue paper and having them bounce back. Why is it important in science that unexpected results are taken seriously, rather than ignored or dismissed as mistakes? What would have happened if Rutherford had ignored the bouncing-back particles?

Challenge 3 marks

Wrap Up

In one sentence, what was the main idea of this lesson?