A scientist is taking temperature measurements at different elevations on Mt. Everest. The temperature at base camp is 22℃. The scientist observes that the temperature decreases by 5℃ every 1000 meters. A student writes a mathematical model for the temperature-elevation relationship: T=(-5℃)E
where T is temperature in degrees celsius and E is elevation in meters.

This mathematical model is wrong. Your answer should explain what is wrong with the original model, and what a correct model would be.