A. Questions for Submission

2.1 Atoms and Diffusion

1. State the atomic hypothesis and contrast it with the continuum view of matter.
2. In what sense does a description of randomly walking atoms give rise to the prediction of diffusion?

2.2. Models and fictions

Does the random walk model of diffusion pose a difficulty for the structuralist (semantic) account of models? Why or why not? What alternatives do you see?

2.3. Randomly walking atoms in action

1. Explain Einstein's model of sugar molecules in water, and what it led him to conclude about the size and number of the sugar molecules.
2. Name an idealisation that this model introduced. Why is this idealisation needed, and why might you expect the model to be successful in spite of it?

Further Discussion (Optional)

• Describe Einstein's account of Brownian motion. How did it support the atomic hypothesis?
• Name an idealisation introduced in Einstein's description of Brownian motion. (There are many.) Is this idealisation different in kind from the one above? Why or why not?