The Albedo Effect & Climate Change Science 8 Unit C: Light & Optical Systems

Program of Studies Outcomes: Unit C Outcome #1 (STS): Investigate the nature of light and vision Unit C Outcome #2 (STS): Investigate how light is reflected, transmitted and absorbed by different materials; and describe differences in the optical properties of various materials. Unit E Outcome #2 (STS): Identify evidence of glacial action, and analyze factors affecting the growth and attrition of glaciers and polar icecaps.

Introduction: On a Hot Summer Day Have you ever… Placed your hand on a black object? Placed your hand on a white object? What was the difference? Why?

Lesson Content: Properties of Light Time: Approximately 10 minutes When light reaches a surface, it can be absorbed and transformed into other types of energy… Electrical (ie. solar cells) Thermal (ie. a hot road) Chemical (ie. trees make sugars)

Properties of Light Light travels in straight lines until it strikes a surface. The type of surface will determine how the light will continue. Transparent: the light continues in a straight path through the object Translucent: the light will be diverted (refracted) after it passes through Opaque: the light will be blocked and not allowed through the object

Reflection Reflection is the process in which light strikes a surface and bounces back off that surface. How it bounces off the surface depends on the Law of Reflection and the type of surface it hits.

The Albedo Effect & Reflection Reflection coefficient Ratio of reflected radiation from the surface to incident radiation upon it. Expressed as a percentage or measured on a scale from zero (for no reflecting power of a perfectly black surface) to 1 (for perfect reflection of a white surface).

Albedo Effect Change to the Earth's albedo is a powerful driver of climate. When albedo increases, more incoming sunlight is reflected back into space. Changes in the polar regions can cause more warming in the entire planet earth system through feedback effects When the white and gray snow and ice disappears, less sun rays are reflected out and instead the heat is absorbed by land and sea - which causes further increase in the warming.

Resource #1: Albedo Video Time: Approximately 5 minutes http://www.youtube.com/watch ?v=rpQNqnRJKeQ&feature=rel ated

Resource #2: Lesson 5 – Topic 1 Time: Approximately 5 minutes http://www.explainingclimatechange.ca/Climate Change 1-8/Lessons/Lesson 5/lesson5.html See how warming over the past 30 years has affected the extent of Arctic sea ice.

Resource #3: Lesson 7 – Topic 1 & 4 Time: Approximately 15 minutes Topic 1: Introduction to Feedback Loops http://www.explainingclimatechange.ca/Climate Change 1- 8/Lessons/Lesson 7/lesson7.html Topic 4: Water Feedbacks – Polar Ice Cap Measuring Tool

What Have We Learned? Reflection Albedo Effect Climate Change & Positive Feedback