• Introduction and Description
• Simulation [Fahrenheit and MPH] [Celsius and Knots]
• Files
• Science Extensions
• Mathematics Extensions
• Contact Information
• Reference and Resource Info

Introduction and Description

As a human you are constantly giving off heat. Every movement you make generates heat to warm the body as active muscles metabolize food faster than muscles at rest. In human beings, the average body temperature is 98.6° F. The human body has mechanisms for keeping itself at or near that temperature as any extreme derivation from the average (98.6) in either direction can harm the body. Some forms of temperature regulation in humans are:

• Perspiring is a common method of keeping the human body cool as it offers an opportunity for wind to blow on moist tissue and cool it.
• Shivering in cold weather is another mechanism of temperature regulation. This rapid movement activates muscles quickly and generates heat.

As described in the above mechanisms the uman body attempts to use its own movement and actions to receive benefit from the environment. What would happen if we moved alot when it was warm. We'd be warmer. And if we had much wind blowing on us in the cold we'd be colder (even without perspiring).

A phenomenon called the Wind Chill factor makes us feel colder in winter than the air temperature really is. This is due to the interaction of air temperature and wind on the human body that is already giving off heat. Both temperature and wind cause heat loss from body surfaces. A combination of cold and wind makes a body feel colder than the actual temperature.

You may hear it mentioned quite often on the news during the winter months. How do news weather persons know that when there is a 10mph wind with a temperature of 10 degrees F that the real temperature we feel is -9 degrees F? 

There is a specific formula that can be used to calculate wind chill.

Simulation [Fahrenheit and MPH] [Celsius and Knots]

Use this calculator to determine the actual wind chill given the air temperature and wind speed.

Files

Now that you have experimented with the calculator try and examine some of the trends associated with temperatures at specific wind speeds.

• Excel File (Download a table to create graphs from data) or Use this Table
• TI-83 Program (Download a program with the real formula):
  • Code:
    Input "WIND SPEED?",W
    Input "AIR TEMP?",T
    0.0817*(3.71*SQRT(W)+5.81-0.25*W)*(T-91.4)+91.4 -> C
    Disp "WIND CHILL:"
    Disp C

Science Extensions

• Biology: What parts of the body lose more body heat? Can this heat loss contribute to the wind chill factor? What damage can be done to the human body from extreme cold, hypothermia, frostbite? 

Mathematics Extensions

• Create a graph from a benchmark temperature of the wind chill temps for each 5 MPH increment.
• Find a line-of-best-fit that describes the general trend of this benchmark temperature. Does the equation of this fit-line agree with the equation used in the calculator program. 0.0817*(3.71*SQRT(W)+5.81-0.25*W)*(T-91.4)+91.4

Wind Chill Chart

Contact Information

• Author: James P. Dildine, 1999
• URL: https://mste.illinois.edu/dildine
• Email: jpd@wlsmail.com

Reference and Resource Info

The Weather Channel Web page: http://www.weather.com/

• Shareware
• Data Sets
• Meteorological definitions