1. Notebook Entry: Inversions Watch this YouTube Video of the Ice Cave Carefully read this web page.

5. Day and Date Here Temperature Inversion Upside-down situation Upside-down situation IMPORTANT: Carefully read this web page IMPORTANT: Carefully read this web pageweb pageweb page Temperature of air in valley is colder than air above it – see next slide. Temperature of air in valley is colder than air above it – see next slide.

6. Helena Valley Warmer on Mt. Helena Colder Air Warmer Air Sketch this.

7. 1. What is so unusual about a “temperature inversion”? (inverted means “upside down”) (inverted means “upside down”) Answer: air at the surface is colder than air above it Answer: air at the surface is colder than air above it colder warmer

8. colder warmer

10. Happen when it is Clear, Calm, Cold Can be poor air quality Go away when storm (wind) comes in

12. Other cities?

14. YouTube Video YouTube Video

17. Why clear nights? Heat escapes quickly out to space Heat escapes quickly out to space Like you sleeping with a blanket Like you sleeping with a blanket

18. Why December and January? It’s colder! It’s colder! Snow reflects sunlight Snow reflects sunlight The angle of the sun is less The angle of the sun is less Days are short Days are short

20. The END