introduction to the multimedia (version 2.0) - foss welcome page

INTRODUCTION TO THE MULTIMEDIA (VERSION 2.0)

OVERVIEWThe FOSS Human Brain and Senses CD-ROM is an integral part of the Human Brain and Senses Course. It provides students with an opportunity to access and interact with simulations, images, videos, and text that can enhance their understanding of concepts. Different sections of the CD-ROM are incorporated in several investigations during the course. You will sometimes use the multimedia to make presentations to the entire class. At other times, individuals or small groups of students will work with the multimedia to review concepts or reinforce their understanding in a game format.

This multimedia component is not optional. At a minimum, you should have one computer with either a CD-ROM drive or a local copy of the CD-ROM files, and a large-screen monitor available for use with the entire class. The following guide provides information to help you set up the simulation on your computers, and provides a tour through the components of the multimedia.

FOSS HUMAN BRAIN AND SENSES COURSE

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EARTH MATERIALS398 FULL OPTION SCIENCE SYSTEM

MULTIMEDIA USER GUIDE

MACINTOSH VERSION

A Power Macintosh G3 or higher, with at least 48 MB of RAM (64 MB recommended), OS 9.x or OS X 10.1 or later, 4X CD-ROM (faster recommended), 16-bit color minimum (thousands of colors) at a resolution of at least 800 ✕ 600.

All of the multimedia is browser-based, so you will need to have a compatible Web browser installed on your system. Compatible browsers are Internet Explorer 5.1 for OS 9 users, Internet Explorer 5.2 for OS X users, and Netscape 7.0 or later for all Macintosh systems.

SYSTEM REQUIREMENTSPC VERSION

Pentium-based (Pentium II or higher) or compatible computer with 48 MB of RAM (64 MB recommended), Windows 98, ME, 2000, or XP, 4X CD-ROM (faster recommended), 16-bit color video card minimum (thousands of colors) at a resolution of at least 800 ✕ 600.

All of the multimedia is browser-based, so you will need to have a compatible Web browser installed on your system. Compatible browsers are Internet Explorer 5.0 or later for Windows 98 and 2000, Internet Explorer 5.5 for Windows ME, and Internet Explorer 6.0 or later for Windows XP. Netscape 7.0 or later is compatible on all PC systems.

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HUMAN BRAIN AND SENSES COURSE


GETTING STARTED

1. FOSS Human Brain and Senses icon. Double-click to start the program.

virtual RAM. You will have to restart your machine each time you change the virtual memory settings.

• Set your monitor to at least thousands of colors. The program runs best with millions of colors, but this setting is not required. You may have to set your monitor to a lower resolution in order to get more colors. For OS 9, use the Monitor Control Panel (accessible either from the Systems Folder or under the Apple on the menu bar) to set color and screen resolution. For OS X, use the Displays setting in the System Preferences (accessible either from the Dock or under the Apple on the menu bar).

• Make sure the sound is turned on and set to the desired level. For OS 9, adjust the sound through the Sound Control Panel. For OS X, use either the Sound System Preferences panel or the volume control buttons on your keyboard.

Insert the CD into your CD-ROM drive. Double-click on the FOSS_HBS disk icon to open the FOSS_HBS folder window, and then open the file named “Human Brain and Senses.htm.” This will launch your browser and load it with the program’s start page.

In all cases, your browser will need to have certain plug-ins installed, namely Flash 7 (or later), Shockwave 8.5, and QuickTime 6 (or later). If you don’t already have these plug-ins on your system, they are available either from the CD-ROM or via the internet.

When you run the Human Brain and Senses program, it provides an option to verify that your browser is configured properly. Choosing this option will take you step-by-step through all the important features that may require additional installation, including Flash 7 (with Shockwave 8.5) and QuickTime 6.

We do not provide support for either Flash or QuickTime. For Flash/Shockwave updates and support, go to Macromedia’s player support homepage.

www.macromedia.com/support/players

For QuickTime updates and support, go to QuickTime’s homepage.

www.apple.com/quicktime or www.apple.com/support/quicktime

MACINTOSH

Get your system ready to run the Human Brain and Senses program.• Turn on virtual memory (OS 9 only).

Test the speed and stability of the Human Brain and Senses program with different amounts of virtual RAM. Allocating too much will slow down your machine considerably. Apple recommends running 1 MB of

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The first time you run the program, select the option to Check Browser, which will take you step-by-step through the verification and installation process. If you try to start the program without first going through this process, you could encounter program malfunctions.

PC

Get your system ready to run the Human Brain and Senses program.• Set your monitor to at least

thousands of colors. The program runs best with millions of colors, but this setting is not required. You may have to set your monitor to a lower resolution to get more colors. Use the Display Control Panel to set color and monitor resolution under Settings, or right-click on the desktop and choose Properties.

• Make sure the sound is turned on and set to the desired level. Adjust the sound through the external speakers.

The Human Brain and Senses program should launch automatically once the CD is inserted into your CD-ROM drive. If your autorun feature is not turned on or an error has occurred, open the FOSS_HBS CD-ROM and double-click on the file Human Brain and Senses.htm. Your browser will launch and load with the program’s start page.

The first time you run the program on a new system, select the option to Check Browser, which will take you step-by-step through the verification and installation process. If you try to start the program without first going through this process, you could encounter program malfunctions.

Credit screen

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PROGRAM BASICSENTERING THE PROGRAM

Upon launching the program, the user can either enter the CD-ROM or check the browser set up. There are two ways to enter the CD-ROM, either through the Main Hall by clicking Enter the Program, or through the Teacher Guide by clicking Enter Teacher Guide.

Letterhead activity.• The games sign lets you select any of

the three available games.• The Optics Bench offers optics-

related activities.• The Teacher Guide allows you to

access all activities by their related lesson.

• The Credits sign shows you the full CD-ROM program credits.

Each part of the CD-ROM is discussed in detail later in this chapter.

1. Click to enter the brain and senses rooms.

2. Click to enter the EEG and MRI labs.

3. Click to go to the games.

4. Click to go to the optics activities.

5. Click to go to the Teacher Guide.

6. Click to see credits.

The Check Browser option verifies that the browser has all the required plug-ins installed and walks through any needed set-up procedure. To quit the program, just exit the browser.

MAIN HALL

When you click Enter the Program on the launch screen, the Main Hall appears. There are six areas that can be accessed from the Main Hall by either rolling the mouse over or clicking the object or sign. • The rotating head offers activities

on the brain and individual senses.• The lab sign offers EEG and

MRI labs and an MRI-related

Human Brain and Senses Main Hall

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Launch screen



QUICKTIME MOVIES

QuickTime movies come in two formats, standard and QTVR. Both run in the Human Brain and Senses program and outside it, via Windows Media Player and QuickTime Player.

The standard format consists of a movie stage and a control bar. Click the single right-hand arrow button on the left-hand side of the control bar to run the movie. Click this button a second time to stop the movie. Click the double-arrow buttons on the right-hand side of the control bar to step through the movie one frame at a time, either forward or backward, depending on the direction of the arrowhead. Click and hold to fast forward or reverse. Some movies will not run well in fast forward and reverse.

GENERAL NAVIGATION AND PRINTING TOOLS

The FOSS Human Brain and Senses CD-ROM uses your browser’s standard navigational controls, including the Back button, the Refresh button, and opening links in new windows. Additional navigational features specific to the program are described in the remainder of this guide.

To print a page from the CD-ROM, you can use -P on the Macintosh or Control-P on the PC to print the active window. The window’s contents will be printed out and scaled to fill a single page.

INFORMATION BOOK

In many of the activities, a red information book appears in the upper

right corner of the screen. Clicking the book opens a text window that provides information about the subject you are viewing and what you can do on the screen.

1. Forward play arrow. Click once to play the movie. Click again to stop the movie.

2. Fast forward/reverse arrows. Click and hold to fast forward or reverse the movie. Some movies will not run smoothly in fast forward or reverse.

If the movie has sound, a button with a speaker icon will appear on the far left side of the control bar. Click it and drag to adjust the sound level of the current movie.

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A QTVR movie allows you to view an object from different perspectives, controlling your perspective with the mouse and keys. These movies may take 30–60 seconds to load.

In these movies you click the object and drag left or right to rotate the view or click and hold at the edge of the frame to let the computer rotate the image.

On both Macintosh and PC machines, pressing the shift key zooms in on an object (if it isn't already at maximum size), and pressing the control key zooms out.

The control bar at the bottom of the movie frame has navigational buttons. If a button is dim, it isn't currently available. The magnifying glasses zoom in (+) or out (-).

The four-way arrow toggles the way the mouse works—either click and drag or click and revolve. The left-pointing arrow undoes the last action. The up arrow reveals hot spots in the movie. Clicking these may start an action sequence or may reset the movie to the beginning.

PLAYING MOVIES EXTERNALLY

If you want to show the movies in a larger format, use Windows Media Player or QuickTime Player outside the Human Brain and Senses program.

When you insert the FOSS Human Brain and Senses (FOSS_HBS) CD-ROM in a Macintosh and double click on the CD-ROM's icon, a folder opens, showing the Human Brain and Senses program, and several sub-folders, including a folder named "Content." Included inside the Content folder is a QTmov folder. Maximize the window and then open this QTmov folder to see the list of movies on the CD-ROM. Refer to the list below to find the file for the movie you want. Double-clicking the icon opens the movie on your computer.

On a PC, open the QTmov Folder found in the folder named "Content" on the FOSS Human Brain and Senses (FOSS_HBS) CD-ROM. Refer to the list below to find the file for the movie you want. Double-clicking a file starts the movie. Note: These files may appear without their “.mov” extension.• Common Cold—cold1.mov through

Cold4.mov• Cow-Eye Dissection—CowEye.mov• Crime Scene—crime.mov• Ear Receptor—ear1.mov through

ear7.mov• Hearing Sensory Pathway—

hearp1.mov through hearp5.mov

QTVR movie screen



• How to Get an EEG—GetEEG.mov• How to Get an MRI—GetMRI.mov• How to Make a Letterhead—

letter.mov• Light into the Eye—flyeye1.mov

through flyeye7.mov• Loss of Taste Sensitivity—loss1.mov

through loss5.mov• Nose Receptors—smell1.mov

through smell3.mov• Pull-Apart Brain—headsce.mov*• Smell Sensory Pathway—

smellng1.mov through smellng5.mov• Synapse Function—synan1.mov

through synan5.mov• Taste Receptors/Distribution—

taste1.mov through taste4.mov• Taste Sensory Pathway—

tastng1.mov through tastng6.mov• Touch Sensory Pathway—

touchng1.mov through touchng6.mov• Vision Sensory Pathway—

seeing1.mov through seeing6.mov• 3D Brain—brain.mov*

* This is in the QTVRmov folder within the QTmov folder.

QUITTING THE PROGRAM

To exit the program, just quit your browser. You can also accomplish this by using -Q on the Macintosh or Alt-F4 on the PC. If you wish to use your Web browser for other purposes, there’s actually no need to quit out of it. In that case, just go to another Web page and the browser will handle everything.

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TROUBLESHOOTINGIf you encounter any trouble using this CD-ROM, the first place to look is on the Frequently Asked Questions page, accessible both directly from the program’s start page and from within the Check Browser section of the program.

On Macintosh OS 9, restarting your computer with minimal extensions (the Base Set for your system) may increase the stability of the program. You can change your extensions through the Extension Manager Control Panel. See the Macintosh User’s Guide (print) or Macintosh OS Help (located under Help on the menu bar) for more information.

On the PC, restarting your computer before you use the Human Brain and Senses program may increase the stability of the program.

If you start experiencing problems while running the program, quit and restart the computer. If problems persist, you may be experiencing systemwide problems on your PC, such as driver conflicts or other errors.

Technical Support. If you have problems running the FOSS Human Brain and Senses CD-ROM and your technical assistants cannot help, please send an e-mail to [email protected].

RUNNING THE PROGRAM FROM YOUR HARD DRIVE

You may find that the limited speed of your system’s CD-ROM drive causes the program to delay when loading media. To improve performance in this situation, or simply as a matter of convenience, it is possible to copy all of the program files from the CD-ROM onto your hard drive (see the CD-ROM license agreement). The following instructions apply to both Macintosh and PC users.

Create a new folder on your hard drive, and give it the name FOSS Human Brain and Senses. With the FOSS Human Brain and Senses CD-ROM in your CD-ROM drive, copy the entire top-level folder named “Content” from the CD-ROM into the new folder on your hard drive. Then, copy the Human Brain and Senses.htm file from the CD-ROM into this folder.

You should now be able to launch and run the program directly from your hard drive, by double clicking on the Human Brain and Senses.htm file.



THE TEACHER GUIDE

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Investigation screen

You can enter the Teacher Guide at startup from the launch screen or any other time by clicking on the Teacher Guide button in the

Main Hall. The Teacher Guide portion of the CD relates the multimedia components of the course to the FOSS Human Brain and Senses Teacher Guide. The Teacher Guide is also the access point for the movies under "Teacher Videos."

The first screen of the Teacher Guide is a list of all the investigations in the course. Click an investigation to retrieve information about it.

Each investigation screen shows• A list of the parts in the investigation.

Click the part title to bring up a brief description of the part and a list of multimedia components associated with it.

• The goals of the investigation.

1. Click a line to learn more about an investigation.

2. Click to return to the Main Hall.

3. Part description or goals.

4. List of parts. Click a title to learn about the part.

5. Multimedia components for a part. Click title to retrieve component.

6. Click a title to return to investigation list.

• A list of multimedia associated with a part. To go to a multimedia component, click its title in the box. (When you leave the multimedia component, you will return to the Main Hall, not the Teacher Guide.)

Clicking the Return button on an investigation screen returns you to the investigation list. Clicking the Main Menu button on the Teacher Guide investigation list takes you to the Main Hall.

TEACHER VIDEOS

Teacher Videos are accessible by clicking on the Teacher Guide in the Main Hall. On the Teacher Videos screen, click the title or icon to bring up a QuickTime movie. Clicking the Return button on the movie stage takes you to the movie list. Clicking the Return button on the list screen takes you back to the Main Hall.

2Teacher Guide investigation list

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ROTATING HEADThe rotating head is in the Main Hall. Roll the mouse over it to get a menu of the brain and five individual senses. Clicking on an item in the menu takes you to a page of links to navigate among information, movies, and interactions about that subject.

For vision, the How the Eye Works section has information about receptors. How the Eye Looks contains information about the anatomy of the organ that is responsible for the initial sense reception. How Vision

Rotating head

Works has information about the sensory pathway. What Can Go Wrong has information about problems that can occur.

The Brain page is unique. The sections there are 3D Brain, Synapse Function, Pull-Apart Brain, and Neuron Growth.

To enter a specific activity, click on the hyperlink listed under the section header. Use the browser's Back button to return to the activity selection page.

The rest of this section describes special navigational features that some screens have.

Vision menu



Brain menu

Hearing menu

Taste menu

Touch menu

Smell menu

Vision menu

Rotating head menu

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VISION: HOW THE EYE WORKS

Field of View. This screen shows how eye position and head shape influence the field of view. The model has eyes that move. Click an arrow on the right side of the screen to move the eyes together or apart. To see the field of view of different animals, click a button for the owl, cardinal, human, snipe, or horse.

Owl field of view

Model field of view



Receptors (Rods/Cones). This screen models the reactions of the retinal rods and cones in five different light levels. Change the light intensity by clicking “More” or “Less.” The left arrow decreases the light level, and the right arrow increases it.

Receptor Density. This screen models rods and cones that fire under five light intensities. Clicking the “More” or “Less”arrows underneath the box increases and decreases the light intensity. The box represents vision at that light. The circle represents changes in the retina, corresponding to the proportion of rods and cones that react. If the arrow button is dim, you have reached the minimum or maximum intensity. You can also select the light intensity by clicking a square underneath the box.

Receptors (rods/cones), no light

Receptors (rods/cones), bright light

Receptor density, no light

Receptor density, bright light

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VISION: HOW THE EYE LOOKS

Human Eye. This screen has a diagram of the human eye, including the outside muscles, a Remove Layer button, an Add Layer button, and a Label button. Clicking the Remove Layer button gradually reveals the interior of the eye. The Add Layer button reverses the process. When a button is dim, it does not function.

Each layer has labels. Apply a label by clicking and holding the Label button, highlighting the desired label, and releasing the mouse button. You can deselect a part by the same process. Select “All” to label all the parts at once, and “None” to remove all labels.

Rolling the mouse over the label highlights that area of the eye. A yellow label indicates an illustration associated with the rollover; click and hold the label to view the illustration. Human eye screen

Retina label highlighted yellow



Position of Eye. This screen has a head, one or two action buttons, and a Reset button. Clicking the action buttons removes or changes the visible layers on the head. When the brain is exposed, you can run a QTVR movie of the brain. (See the section called QuickTime Movies on page 402 for more about viewing QuickTime videos.) The Reset button resets the screen to the initial picture.

Eye position screen

See through skin screen

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TOUCH: HOW THE SKIN WORKS

Receptors. To observe reactions to different touches, click one of the four buttons, Pressure, Pain, Heat, or Cold. To stop a running reaction, click on its depressed button.

Receptor Fields. This screen demonstrates why various areas of skin react differently to differently spaced probes. Click the

Test button below each skin patch to lower the probe to touch the skin. If a receptor is touched, it fires a yellow jolt of current below the skin patch. If two receptors are touched, they fire two jolts of current. Click the Gap button to change the size of the gap on all three tweezers at once (small, medium, or large).

Receptors, pressure screen Receptors, fields screen

Receptor fields, small gap, test one screen Receptor fields, test all three screen



TOUCH: HOW THE SKIN LOOKS

3D Finger. This screen identifies skin parts. Apply a label by clicking and holding the Label button, highlighting the desired label, and releasing the mouse button. You can deselect a part by the same process. Select “All” to label all the parts at once, and “None” to remove all labels.

TOUCH: WHAT CAN GO WRONG

Leprosy. This screen compares normal and leprous skin. Clicking the Pain button shows the reaction to a finger press.

Paralysis. This screen illustrates where damage that causes paraplegia or quadriplegia is likely to occur. Click a word to see where the damage originates and where the affected area is. You can toggle between the two conditions by clicking on either word, or return to the initial interface by clicking the selected word.

3D finger screen

Leprosy, comparison screen

Paralysis screen

Leprosy, pain screen

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HEARING: HOW THE EAR LOOKS

3D Ear. This screen identifies ear parts. Apply a label by clicking and holding the Label button, highlighting the desired label, and releasing the mouse button. You can deselect a part by the same process. Select “All” to label all the parts at once, and “None” to remove all labels.

HEARING: WHAT CAN GO WRONG

Ear Infection. This screen compares hearing in a normal ear and an infected ear. Click the Hear buttons to play a scale as it would be heard by the normal or affected ear.

Hair Cell Damage. This screen compares normal and damaged hair cells. A movie on the bottom of the screen starts from a cross section of an entire ear and zooms in to the cochlea. Click the Hear buttons to play a scale as it would be heard by the normal or affected ear.

3D ear screen

Cochlea label clicked to show area enlarged

Hair cell damage screen



TASTE: HOW THE TONGUE LOOKS

3D Mouth. This screen identifies tongue parts. Apply a label by clicking and holding the Label button, highlighting the desired label, and releasing the mouse button. You can deselect a part by the same process. Select “All” to label all the parts at once, and “None” to remove all labels.

To see a taste area, click the box that corresponds to the area.

3D mouth screen

Circumvallate papilla label highlighted and area enlarged

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BRAIN: PULL-APART BRAIN

For general directions on running this QTVR movie, see QuickTime Movies on page 402. Note: This movie may take up to 60 seconds to load.

You can view the pull-apart brain in two ways. Click Halve to see the two hemispheres of the brain after it has split in two. Click a hemisphere to flip it over. Click Explode to see the different parts

Halved brain

Exploded brain

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of the brain independently of each other. Click a part to see another QTVR of just that part.

Clicking and dragging the mouse across the movie in either direction plays the movie forward or backward. Clicking a hot spot on the brain hemispheres zooms in or out. Double-clicking a hot spot in the exploded brain zooms in on that part of the brain, allowing you to revolve it.



IMAGING LABRoll the mouse over the lab sign to bring up the imaging lab menu, which has information about MRIs and EEGs. Select the item you want by clicking on it.

MRI LAB

The MRI Lab has a movie of a girl getting an MRI scan, MRI images of the brain at different ages, and MRI images taken along different axes. When you enter the lab, you see an MRI image of the center sagittal section of a person's head. At the right are controls that let you move left or right in a parallel plane. You can also select axial and coronal planes for the MRI image. “Left” and “Right” correspond to the scanned person's head, not to your left and right.

MRI sagittal, adult female scan screen

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Click Age Comparisons to see axial and sagittal MRI sections of an infant, an adolescent, an adult, and a senior.

MRI sagittal, age comparisons screen



LETTERHEAD

The Letterhead activity allows you to examine the MRI-like slices of a virtual letterhead and to see a movie (How to Make a Letterhead).

You can slice a virtual letterhead in three ways, through the axial plane, the sagittal plane, or the coronal plane. You can change from axial to coronal or sagittal and vice versa at any time in the slicing process. The stage will reset to the beginning, with the letterhead unsliced.

To see the movie, click on the How to Make a Letterhead button. The movie is also accessible through the Teacher Guide in the Main Hall.

Slicing a letterhead, opening screen

Slicing a letterhead, axial slices screen

How to Make a Letterhead movie screen

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EEG LAB

The EEG Lab has various EEG scans and a movie (Get Scanned). The initial screen shows a vision EEG scan mapped on a two-dimensional head. Below the EEG scan is a scale that correlates the color of the EEG to amount of brain activity. The Graph button at the right overlays an EEG graph on the scan.

Click Touch to see EEG activity during a touch stimulus. Click and hold Conditions to select a condition that affects EEG activity. Side-by-side EEGs show the normal activity and that of the affected brain.

Vision EEG opening screen

Show electrodes screen

Show graph screen

Get scanned movie screen

Conditions, anorexia screen



GAMES ROOMRoll the mouse over the games sign in the Main Hall to access the games menu and click on an item to select Memory Game, Reaction Timer, or Optical Illusions.

MEMORY GAME

The Memory Game tests you by way of seeing objects, by reading the objects’ names, by hearing objects’ names, or by any combination of these three methods. You can move objects around on the screen to determine if grouping helps memorization.

On the first screen choose the memorization method by clicking the box next to “Sound,” “Images,” or “Words.”

These boxes are toggle switches. The timer is set at 60 seconds; you can raise or lower the memorization time. For sound, the smallest time interval is 20 seconds. Once you begin the game, you cannot exit until you have finished the memorization and testing sections.

Stop the memorization period at any time by clicking the finished button. When sound is playing, click and hold the button.

Memory Game first screen

Playing the game screen

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The testing screen is a small lined text box. Make sure that Caps Lock is not engaged. It is not necessary to type in the name of the memorized object exactly where it was during the memorization period. Correct answers completely replace the object name, if spelled in lowercase letters, and have no spaces before or after the name. Some synonyms are accepted.

Click Test Your Answers. Correctly memorized objects appear in yellow bars; others appear in red bars. Correct and incorrect answers appear in scrolling text boxes in the lower corners. If you choose sound, words appear as the word is spoken.

What can you remember? screen

Checking answers screen



THE REACTION TIMER

Reaction Timer tests the speed at which you learn a maze. When you click the Start button, three colored squares appear in a maze, and a timer starts. The timer stops after you have moved each square through the maze. When the timer stops, the time in seconds appears in both the Reaction Time box and the Compare Your Trial Times box. You cannot exit Reaction Timer until the timer has stopped. There is a Fixed and Random maze selector button.

Test your reaction opening screen

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Start game screen

Finish game screen

Game being played



OPTICAL ILLUSIONS

This brings up a screen containing six different optical illusions. Click a button to view the corresponding illusion. In the perspective illusion you can move the two purple dolls. In the table illusion the two tabletops look like they are different shapes. To prove they're really the same, click the right table to turn it on its end, then click and drag the tabletop to the other table.

Perspective illusion

Size perception

Size perception check

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In bumps and dents you can change what appears to be a bump into what appears to be a dent by clicking one of the four lightbulbs around the gray square. Another way to illustrate this illusion is to choose either the top or bottom lightbulb and look at the screen upside down. It may take closing your eyes as you switch your perspective to see the effect.

Demonstrate the Zöllner square and Zöllner lines by clicking on the illusion in the center stage. The Fraser circle automatically plays a demonstration movie loop.

Bumps and dents

Fraser circle

Zöllner square Zöllner lines



OPTICS BENCHThe Optics Bench has three activities: Bending of Light Through Materials, Lenses, and A Visit to the Optometrist.

BENDING OF LIGHT THROUGH MATERIALS

To see how light bends as it passes through different media, choose the

materials from the pull-down menus. Change the angle of light by clicking and dragging the lightbulb anywhere to the left of the left-hand bar.

When materials 2 and 3 are water, an eye appears in the upper right corner of the screen. Click the eye to see how the bending of light through materials relates to the bending of light in the eye.

Bending of light opening screen

Air-Water-Water screen

Where does light bend in the eye screen

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LENSES

You can manipulate the lenses diagram in several ways. Move the arrow across the screen by clicking and dragging it. The closest that the object can be dragged toward the lens is where a virtual image would be created.

Change the curvature of the lens by dragging the red button on the slider bar. Add or remove a second lens by clicking the appropriate toggle button. Only one lens can be added at a time.

Other options are adding two more light rays for a total of four lines by clicking Draw Four Lines, and adding the focal plane, Show Focused Image. Adding the focal plane effectively illustrates that adding a convex lens brings the focal plane closer to the lens.

Lenses opening screen

Add concave lens screen

Draw four lines screen



A VISIT TO THE OPTOMETRIST

The optometrist screen shows an eye facing a screen (representing a patient looking at an eye chart) and a book containing the eye chart. You can test the near and far vision of different patients and determine if a lens of +/–1, 2, or 3 will correct their vision.

The initial screen is a patient with normal vision that needs no correction, tested for near vision. To test a patient's far vision, click Test Far Vision. To add a lens to determine the effect on the patient’s vision, click either the Concave or the Convex button. A box with three lenses appears (+1, +2, or +3 diopter for convex lenses; -1, -2, or -3 diopter for concave lenses), from which you can select a lens

to try. To change the lens, click the lens in the box or click the other lens toggle button. To remove all lenses, click the chosen toggle button.

The lenses do not mimic exactly what the eye would do with corrective lenses. A concave lens used to correct a nearsighted person's far vision typically need not be removed for near vision, because the eye can compensate for this; in this model it is removed nonetheless. However, the model correctly shows that a convex lens used to correct farsightedness needs to be removed for far viewing distances.

To change patients, click the Next Patient button. The movie See an Optometrist in Action shows some routine tests during an annual eye exam.

A visit to the optometrist opening screen

Adding a convex lens screen

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