Teaching Physics with the Physics Suite

Edward F. Redish

Home | Action Research Kit| Sample Problems | Resources | Product Information

Problems Sorted by Type | Problems Sorted by Subject | Problems Sorted by Chapter in UP

Alice and the looking-glass

Alice faces a looking glass (mirror) and is standing at a level so that her eyes appear to her to be right at the top of the mirror as shown in the figure. At the position she is standing, she can just see her belt buckle at the bottom of the mirror. If she steps back far enough

  1. she will be eventually able to see all of herself in the mirror at the same time.
  2. she will see no change in how much of herself she can see.
  3. she will see less of herself as she steps back.
  4. some other result (explain)
Put the letter of the choice that completes the sentence correctly in the box at the right below and explain why you think so with a few sentences and some rays on the diagram.

Note to the instructor: This is another surprise for many students. A large majority think you can see more of yourself by stepping back. What experiences do you suppose led them to that conclusion?

Not finding what you wanted? Check the Site Map for more information.

Page last modified October 31, 2002: OP19