Light

How do you LIGHT Up your world ? Part I-Virginia SOL 5.3 Examining Light 2004 with Hands-On Activities Compiled by, Marjorie Anne Wallace Elementary Science Resource Teacher 2002-2005 / NNPS & NSF Coop Agreement

Welcome to a power point presentation on LIGHT. • We will investigate the following: • 1. What is light? • 2.What are some sources of light around us? • 3. What are opaque, transparent, & translucent objects? • 4. What is a light wave? • 5.Are there any hands-on/minds-on activities I can do to learn more?

LIGHT Standards • National Science Education Standards • Physical Science: Content Standard B • As a result of the activities in grades K-4, all students should develop an understanding of light, heat, electricity, and magnetism.

• Virginia Standards of Learning 5.3 a-e: • The student will investigate and understand basic characteristics of visible light and how it behaves. (*Key concepts, 5.3a-e, are listed in your teacher curriculum guide)

Light • Our primary source of light is the sun. • Light travels in straight lines at a speed of 186,000miles per second. • *Light waves travel faster than sound waves! • Light energy from the sun travels through space , reaches earth, and some of it turns to heat energy and warms the earth’s air. • Light from the sun also travels to the cells of green plants (producers) and is stored as energy. • When light reaches an object, it is absorbed, reflected, or passes through it.

Sensing Light • Humans have two light detectors. • Do you know what they are called?

How many sources of Light can you list and explain? • SUN=warms air, water, and land. • Fire=provides heat, light, and cooking fuel. • Lightning= • Firefly= • Flashlight= • Light bulb= • Laser beams= • Optical telephone fibers= *Traffic lights=

*AIMS: Primarily Physics: Light Sources Activity

Can you answer these 5th grade 2003-SOL queries? • 1. A person will see a flash of lightning before they hear the thunder that goes with it because? *SOL 2003 querie #14/CORE 1 Exam (5.3e) • 2.Can you draw a long wavelength and a short wavelength next to it? *SOL2003 queire #9/CORE 1 Exam(5.3a) • 3.What scientific tools are used to study light? *SOL2003/CORE 2 Exam(5.3b)

• 4. Can you contrast objects that are transparent, translucent, and opaque? *SOL2003/CORE 2 Exam(5.3d)

“Just Passing Through:” What happens when light strikes glass? Or waxed paper? Or a book? • If light travels through an object it is =transparent • If light is blocked by an object and a dark shadow is cast it is= opaque. • If some light passes through but not all and a light shadow is present it is=translucent. *AIMS:Primarily Physics: Just Passing Through Activity

What happens when light hits these objects? • • • • • • • • •

Glass of water School bus window Notebook paper Waxed paper Plastic wrap Tissue paper Cardboard Textbook Hand lens…

Transparent objects: • • • • • • • • •

The windows on a school bus, A clear empty glass, A clear window pane, The lenses of some eyeglasses, Clear plastic wrap, The glass on a clock, A hand lens, Colored glass… ALL of these are transparent. Yes, we can see through them because light passes through each of them.

Translucent objects • • • • • •

Thin tissue paper, Waxed paper, Tinted car windows, Frosted glass, Clouds, All of these materials are translucent and allow some light to pass but the light cannot be clearly seen through.

Opaque objects: • • • • • • •

Heavy weight paper, Cardboard Aluminum foil, Mirror, bricks, buildings, Your eyelids and hands, Solid wood door, All of these objects are opaque because light cannot pass through them at all. • They cast a dark shadow.

Let’s find out how light travels? • Simple Activity: 1 working flashlight • 1. Shine a flashlight on a wall. • 2. Does light from the flashlight reach the wall? How do you know? • 3. What evidence do you have showing light travels in a straight line? • 4.Record answers in your science journal • 5.Move closer with the flashlight. • Any changes? *Write a story about light.

Understanding Waves • • • •

The traditional hands-on/minds-on activities: 1. “slinky lab: A Wave Simulation!” as well as 2. “Waves in Action” (visual learner), and 3. “Act It Out!Waves Tall and Small” (kinesthetic learner) activities will help children understand waves better. *Science Museum of Virginia: Light & Sound www.smv.mus.va.us

• *Unitedstreaming movies:”Out of Darkness: An Introduction to Light: Facts About Light.”(auditory & visual learners). *Check with your building technology dept for your schools password.

What is light really? Electromagnetic radiation waves • Light waves are three dimensional. • Light waves vibrate in all planes around a center line. • The waves have high points called “crests.” • Waves also have low points called “troughs.” • *The distance from one crest to the next crest is called a “wavelength.” • *The number of waves passing a given point in one second is called the “frequency.”

wavelength

*A Science Museum of VA: Light Science Activity

Notice the wavelength is long(Radio waves) and gets shorter (Gamma Rays)

A wave simulation:

*Science Museum of VA A Wave Simulation Activity/Demo OR GEMS:”Invisible Universe” Comparing Wave Makers

• Materials: 1 long spring or rope • 1. Teacher and a strong student will hold either end of the coiled spring tightly braced against their body. • 2.Teacher will walk away from the student until the spring is loosely stretched between them. • 3.Gently snap the spring up and down once to send a wave of energy to the student’s hand. It will bounce back, or reflect, from the stationary end. • 4. Point out each wave has a crest (high half) and a trough (low half). Check for understanding

*Electromagnetic Radiation • Electromagnetic radiation can be described as a stream of photons. Each photon traveling in a wave-like pattern, moving at the speed of light and carrying some amount of energy. • The only difference amongst radio waves, visible light, and gamma-rays is the amount of energy of the photons. Radio waves have photons with low energies. Microwaves have a little more energy than radio waves. Gamma -rays and cosmic rays have highest energy waves and are the deadliest. *Page info from NSTA Conference 2004

Don’t’ forget…longest waves (radio) ..to shortest waves (cosmic)

*Page info from NSAT Conference 2004

1.Acting It Out! Waves Tall & Small Activity(The electromagnetic family)

+2.Scaling the Spectrum Activity • Materials: • 1. 9 volunteers • 2. paper & pencil. • These 2 activities help to explain the electromagnetic spectrum and dispel some of the common misconceptions.

*Science Museum of Virginia Acting It Out! Activity + Scaling the Spectrum Activity OR GEMS: Invisible Universe Comparing Wave Makers I.

Power point II covers the electromagnetic spectrum!