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You will need:

• Containers of various sizes and shapes, including boxes and plastic bottles
• A large wood or cardboard base
• A blow dryer
• A desk lamp or flashlight
• Pins
• Paper
• Scissors
• Tape and glue

What to do:

Stick the containers to the base to make a model of the city. Make the model realistic by drawing out a street plan and arranging the buildings in well laid out blocks.

Cut small strips of paper and fold them around the pins to make little flags. The paper should be able to spin around freely if you blow on it. Stick the flags on various parts of your model – at street level and on the tops and sides of the buildings.

Set up the fan so that it is level and pointing at the tops of your model skyscrapers. Turn all the flags so that they are at right angles to the direction the fan is pointing. Turn on the fan. What happens to the flags? Which parts of the city have felt the greatest effect of the wind? Move the fan to a new position, set up the flags as before, and repeat the experiment. Describe your results.

Darken the room and use the lamp or flashlight to represent the sun. Move the light over the model in a high arc. Notice how the shadows of the buildings move and change size. Do any of the shadows of the taller buildings extend beyond the downtown area? If so, these shadows might fall on parts of the city where many people have their homes. Decide if this is a problem and, if so, redesign your model to reduce the effects of shadowing.


Taking it further:

Invent your own section of a city or use ideas from a city that you know well. You might also study the effects, for example, of demolishing one of the skyscrapers in your model and replacing it by a much higher one.

Instead of an entire section of a city, you could focus on just a small cluster of skyscrapers. One of the effects of tall buildings is that they tend to cause winds to spiral down to street level. You could study this by putting several high structures together, marking their sides and the model streets with pin flags, and then directing air from a powerful fan at the tops of the buildings. Can you produce a spiraling air pattern? If so, can you get rid of the wind at street level by rearranging the buildings or spacing them farther apart? Read about this effect and find out how architects attempt to avoid the problem in practice.