Passing cars

Resources

Passing cars (worksheet)

Passing cars (PowerPoint)

Teaching notes

The two factors that create this illusion are the width of the road (and how it appears to funnel), and how close the inner cars are to each other. Students should be alerted to these factors and discussion can take place as to whether they are ultimately important or not.

Since this puzzle demonstrates how easily the eye can be misled, it could act as a starter for a discussion about other forms of deception, eg in persuasive writing or speaking. A particular focus might be the media – misleading images are often used in journalism and advertising to support points of view.

Problems can occur in the discussion if students mention large wing mirrors – for the purposes of this puzzle, wing mirrors can be ignored.

Solution

There is just enough room for the cars to pass each other.

Extension

Students could be asked to evaluate the puzzle’s effectiveness, perhaps in comparison with other optical illusions from this section. They could ask the following questions:

• What is the ‘hook’ that creates the illusion?
• Is the illusion convincing?
• How could it be improved?
• What elements can they change while still maintaining the illusion?