Climate in cities

Basics

Worksheet: Wind in the city

Sheet 1: Measurement of wind

1. Measurement of wind speed

Wind can be defined as the movement of air.
Wind speed describes the distance, the air covers within a certain time.

Typical measurements of wind speed are:
- meters per second (m/s),
- kilometres per hour (km/h)
- miles per hour (mph).

A helpful website about wind speed (including a wind speed-converter e.g. from m/s into km/h) can be found on site of the Icelandic Meteorological Office: www.vedur.is/english/wind_eng.html

To ease the understanding of the m/s measurement, the Icelandic Meteorological Office offers this table and diagramme:

wind speed in m/s   description > 30 extreme wind, dangerous 20-30 very windy, caution is advised 10-20 considerable wind, may lead to difficulties 5-10 rather slow wind < 5 very slow wind

2. Wind speed in Cities:

Chicago has a reputation for being the „Windy City“ of the USA.

- Find out, what the average annual wind speed of Chicago is!
- Is it correct to name Chicago “Windy City”? Discuss!
- Find out, where and when wind speed was or still is extremely high.

The following links will help you:

- www.cityofchicago.org/DPD/ChgoFacts/Climate.html
- www.aws.com/aws_2001/schools/wx_mania/WNCWeatherManiaNovember
222002.html
- www.census.gov/pubinfo/www/radio/pa0412.htm
- http://classroom.aws.com/main.asp

(Very interesting link - you can login at any American school and check the weather! Click “Tools” and then map gallery and you will find an overview of American wind speeds, temperatures etc. at different places! Also the “meteorology match game” and “extreme weather” are worth clicking!)
 

3. Experiment: Is your hometown also a windy city?

There are 3 ways to measure wind speed:
- With the help of a wind hose (only shows whether the wind speed is high or low)
- Easy comparison of wind speed with the help of a pinwheel (only allows the comparison of wind speeds at different places)
- Professional wind speed measurement instrument (used at meteorological institutes – ask your physics teacher, whether your school has this instrument).

To find out whether your hometown can also be called a “windy city”, you can do the following experiment and compare the wind speed in an easy way at different spots at your home town with the help of a pinwheel: 

 

What you need:
- pinwheel with pointer
- stopwatch
- sheet of paper to protocol the measurement (see below)

What to prepare:
- fix the pointer (paper arrow) at the pinwheel (photo)

Idea of experiment:
- Wind speed can be compared at different spots when the number of turns of the pinwheel is measured within a certain time.

a) To find out, how often your pinwheel turns at a specific time and place, you first have to fix the pointer on one of the wings of the pinwheel.

b) How often does your wheel turn within one minute? Count how often the pointer passes the bottom within 60 seconds.

c) Now write down the number of turns and the place.

d) Go to another place and do the same. Now you can compare the two places and see, where the wind blew stronger.

Let`s start:
Now take your worksheet (see below!) and your equipment and compare the wind speed at different locations!

Advise:
Compare the wind speeds at corners with those at big and narrow streets! What can you find out?

If you have a professional windspeed measurement instrument at your school take it with you and measure the real windspeed at a certain place!

About this page:

- Author: Dr. Schrettenbrunner / Dr. Schleicher - University of Nürnberg - Germany
- scientific reviewing:
- educational reviewing: Julia Heres
- last update: 09.09.03