Workshop 2: Laws of Light

 

DESCRIPTION

Light energy has predictable properties when it interacts with matter that we refer to as reflection and refraction. In this workshop we will explore what happens to light when it strikes a smooth surface, a rough surface, or a transparent surface. In particular, we will examine several big ideas about light through viewing demonstrations with light and mirrors, visiting an artist and an astronomer who use mirrors in their work, watching fifth grade students investigate refraction, and listening to experts talk about light. We will also ask you to think about some situations involving reflection and refraction.

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LEARNING OBJECTIVES

Participants will understand that:

• Light energy can be absorbed, reflected, and refracted by matter.
• Light energy is reflected off objects at a predictable angle. The angle of the incoming light equals the angle of the outgoing light. This is called the law of reflection.
• Light energy reflects off smooth and rough surfaces following the law of reflection. Rough surfaces create a scattering of the photons, which prevents us from seeing images.
• Light energy changes speed (and thus direction) when crossing the boundary between two different transparent materials in a process called refraction.
• The refractive property of transparent materials can be used to make lenses that focus light (e.g., cameras, eyeglasses, telescopes).

 

STANDARDS

National Science Education Standards

K-4 Standards: http://bob.nap.edu/html/nses/html/6c.html#ps

• Light travels in a straight line until it strikes an object. Light can be reflected by a mirror, refracted by a lens, or absorbed by the object.
  Content Standards: K-4: Physical Science: Light, Heat, Electricity, and Magnetism
  
  
• Scientists develop explanations using observations (evidence) and what they already know about the world (scientific knowledge). Good explanations are based on evidence from investigations.
  Content Standards: K-4: Science as Inquiry: Understandings About Scientific Inquiry

5-8 Standards: http://bob.nap.edu/html/nses/html/6d.html#ps

• Energy is a property of many substances and is associated with heat, light, electricity, mechanical motion, sound, nuclei, and the nature of a chemical. Energy is transferred in many ways.
  Content Standards: 5-8: Physical Science: Transfer of Energy
  
  
• Light interacts with matter by transmission (including refraction), absorption, or scattering (including reflection). To see an object, light from that object— emitted by or scattered from it — must enter the eye.
  Content Standards: 5-8: Physical Science: Transfer of Energy

K-12 Standards: http://bob.nap.edu/html/nses/html/6b.html

• Although most things are in the process of becoming different — changing — some properties of objects and processes are characterized by constancy, including the speed of light, the charge of an electron, and the total mass plus energy in the universe. Changes might occur, for example, in properties of materials, position of objects, motion, and form and function of systems. Interactions within and among systems result in change.
  Content Standards: K-12: Unifying Concepts and Processes: Constancy, Change, and Measurement
  
  
• Models are tentative schemes or structures that correspond to real objects, events, or classes of events, and that have explanatory power. Models help scientists and engineers understand how things work. Models take many forms, including physical objects, plans, mental constructs, mathematical equations, and computer simulations.
  Content Standards: K-12: Unifying Concepts and Processes: Evidence, Models, and Explanation

 

American Association for the Advancement of Science (AAAS) Project 2061 Benchmarks
http://www.project2061.org/publications/bsl/online/bolintro.htm

By the end of the 2nd grade, students should know that:

• A model of something is different from the real thing but can be used to learn something about the real thing.
  Common Themes: 11b Models: K-2
  
  
• One way to describe something is to say how it is like something else.
  Common Themes: 11b Models: K-2

By the end of the 8th grade, students should know that:

• Energy cannot be created or destroyed, but only changed from one form into another.
  The Physical Setting: 4e Energy Transformation: 6-8
  
  
• Models are often used to think about processes that happen too slowly, too quickly, or on too small a scale to observe directly, or that are too vast to be changed deliberately, or that are potentially dangerous.
  Common Themes: 11b Models: 6-8
  
  
• Different models can be used to represent the same thing. What kind of a model to use and how complex it should be depends on its purpose. The usefulness of a model may be limited if it is too simple or if it is needlessly complicated. Choosing a useful model is one of the instances in which intuition and creativity come into play in science, mathematics, and engi-neering.
  Common Themes: 11b Models: 6-8

 

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