Lesson Plan

3. Explore the history of atomic models

KS4-21-03

Intent

Lesson Outcomes

  • Name some of the scientists who worked on models of the atom and place them in chronological order  
  • Describe earlier models of the structure of the atom
  • Explain the results of the alpha scattering experiment and how this was used to deduce a new model of the atom

National Curriculum

  • The nuclear model and its development in the light of changing evidence

Working Scientifically

  • Understand how scientific methods and theories develop over time.
  • Use a variety of models, such as representational, spatial, descriptive, computational and mathematical to solve problems, make predictions and to develop scientific explanations and understanding of familiar and unfamiliar facts

Resources

Resources: Class presentation and handout.

Handout: Describe the history of the atom in chronological order. Summarise the alpha scattering experiment and explain the evidence for atomic structure. Describe the contributions of Bohr and Chadwick. The last question extends knowledge as a challenge question. 

Rocket words

  • Democritus
  • John Dalton
  • J.J. Thomson
  • cathode
  • Ernest Rutherford

Implementation

Starter

As you go through the lesson, write a sentence about the contribution both Niels Bohr and James Chadwick. Discuss with the students how science develops over time and that many of the advancements were made in the recent history of the world. Explain how this began in a period of history called The Enlightenment, or rationality and reason.

Main Teaching

Use the handout to broaden the understanding and learning around the topic. Draw the scientific discovery together in chronological form. Use the analogy of a snooker table to explain the alpha particle experiment and angle of deflection. Show that speed and force can change the angle of deflection. Discuss the advancements to Rutherford's theory that were made by Bohrs and Chadwick. The students are to complete all of the examination-style questions with a full explanation.

Draw a fully labelled diagram of Rutherford’s alpha scattering experiment, showing possible pathways of the alpha particles.

Ensure that the students understand how the three particles – protons, electrons and neutrons – were discovered and by whom.

Particle physics is discovering ever smaller particles – Google ‘quarks’.

Career Film: This is Francis Schofield. Francis works as a Graduate Chemist for National Nuclear Laboratory.

Expert Film: This is Francis Schofield and works as a Graduate Chemist for National Nuclear Laboratory. Francis talks about the history of atomic models.

Mission Assignment

Read the first page of the handout and summarise the names of each scientist and their key discovery. 

Answer questions on the handout to describe the alpha scattering experiment and explain how the results lead to a new model of an atom being deduced. 

Describe the contributions of Bohr and Chadwick to the model of an atom.

Challenge Task:

  • The last question on the handout looks at the work of Chadwick.
  • Describe the experiment. Apply knowledge of the alpha scattering experiment to explore how this improved understanding of atomic structure.
  • Research quarks. What is it? How was it discovered?

Impact & Assessment Opportunities

Plenary

Complete the summative quiz on the presentation to assess learning.

The students can devise a mnemonic to remember the chronological order of the scientists and the contribution to the model of the atom.