Light How does light move? Part One:

When a light shines it sends out waves of light. These waves travel in all directions.

Each wave travels in a straight line. These lines of light are called rays.

Let’s take a look at one of these rays and how it interacts with other mediums or states of matter.

A ray of light will travel along its path until something gets in its way. When this happens a variety of things can occur.

If we place a mirror or a shiny reflective surface in the path of the ray, it will cause the light to bend and travel in a different direction. Notice it will still travel in a straight line.

When light bounces off of the surface of an object it is called Reflection.

Light can travel through many forms of matter, such as Air, Water, and Glass. But most forms of matter won’t let light pass through it.

When a ray of light hits this wall, the wall will stop the light. When a form of matter stops light, it is called absorption.

When light is reflected or absorbed by an object it is opaque. You can not see through Opaque objects. Opaque objects are solid and they do not allow light to pass through them.

Some objects are clear enough to allow some light pass through but not all. Translucent objects absorbs most of the light, but still allow some of the light to pass through it.

Translucent objects are either thin or cloudy in some way. You can see light through the item but not shapes or images. Just like these clouds.

A transparent object doesn’t reflect or absorb much light at all, it allows almost all of the light to pass through it.

Clear glass, or a window is a great example of transparent matter. Although a little of the light is reflected back. See the little reflection in the window.

Quiz Time Look around the room, and name five items that are opaque, four that are transparent, and one that is translucent.

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Teacher Lecture Notes This is a straight forward lesson introducing the vocabulary. Hands on comes during the quiz when the students look for examples of the three types of matter. When students are done go around the class and talk about the items they find. I have them each offer up one example at a time, naming something that hasn’t been named yet. This lesson works well with the laser game website project. On the next slide

Laser Website Project: I found this web site a few years ago by a fluke. It so fit our curriculum and more, I quickly added into my light unit. The site is a simple laser game using a single beam of light, mirrors, splitters (aka Prisms), and light bulbs. The point is to get the laser beam to shine directly on the light bulb. Each round gets a little more difficult. There are 25 rounds in all. At the completion of each level the game will give a code, this code can be used to skip ahead to the level they stop at on future visits to the site. The code can also be used to show that they have beaten the level. Please play the game a while so you can better explain it to your students. Along with the basic principles of light this activity also reinforces higher order, and strategic thinking. These games are also highly addictive! Your puzzle solving students will not be able to get enough of them. After level 8 or so the levels start to get very difficult. The project: I give ask the students to simply solve levels I tell the students that it is my expectation that they do reach that level. How ever I do not tell them that I will not grade them down if they don’t. To get to level 6 is easy, so that earns a 90. Levels 7,8,9 each give them 3.33 points with level 9 giving them a 100 and level 10 giving them a 105%. 5 = 85; 4=75, 3 or lower = 65%. I do allow students to work on this at home if they have a computer and internet. I offer an incentive to go beyond and complete 11 – 25. I’ll let you decide on your own motivator. If this is a problem in your school, then you can give a few sessions for them to work on it in the computer lab. If this is a 100% in-school-project you might want to give them at least 4 sessions in the lab to finish the first 10 levels. I just make a work sheet with 25 lines on it with the Promise of Honorable play at the top along with the directions. The codes for levels 1 – 23, the Honor Code, and directions are on the next slide. I haven’t had time to beat the last three levels. Like I said they are tough! Just cut and paste the parts onto your own worksheet. Have fun!!! Page 1 of 2

Laser Website Project: The code for all of the levels are: 1.bios 2.cpu 3.usb 4.rdram 5.w2k 6.macos 7.irq 8.PCM 9. SVGA 10.os/2 11.TCP/IP 12.ascii 13.input 14.io 15.cdrw 16.dma 17.csma 18.ccd 19.dsl 20.ps/2 21.rambus 22.acpi Promise of Honorable Play: I here by to solemnly swear that I will not get help from any other person including but not limited to: my Mother, Father, Brother, Sister, Cousin, Aunt, Uncle, Grandma, Grandpa, Boyfriend, Girlfriend, Friend-Friend, Dog, Cat, Fish, Bird, Lizard, Snake, or any other living sentient being not listed above. I promise that I will do my own work for this project. ______________________________ Your Signature Here Page 2 of 2 Directions: Your task this time is a simple one, go to this web site and complete the first ten levels ON YOUR OWN! If you want to keep going each additional level will give you a bonus of _______________________. Just write the pass word for each level in the box.

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