C a p t i o n e d M e d i a P r o g r a m VOICE (800) 237-6213 TTY (800) 237-6819 FAX (800) 538-5636 E-MAIL [email protected] WEB www.cfv.org #10397 THE INCREDIBLE WORLD OF THE MICROSCOPE RAINBOW EDUCATIONAL MEDIA, 2001 Grade Level: 4-8 25 Minutes CAPTIONED MEDIA PROGRAM RELATED RESOURCES #8816 THE MICROSCOPE: OUR WINDOW ON THE WORLD #9058 THE CELL Funding for the Captioned Media Program is provided by the U.S. Department of Education Producer, Writer & Director: Peter Matulavich Consultants: Ira Jones, Ph.D. Introduction Dept. of Biological Sciences, California State University, Objectives Long Beach Michael Worosz, M.A. Summary Curriculum Consultant Review Questions Videography, Animation & Editing: Peter Matulavich Discussion Questions Special Thanks To: Steve Barlow, Ph. D. Electron Microscope Center, Activities San Diego State University Glossary Dan McKinney Swift Instruments Bibliography Jones Biomedicals & Laboratory Websites Pinecrest School, Woodland Hills, CA Script Video and Teacher's Guide produced for Rainbow Educational Media by Peter Matulavich Productions San Dimas, California INTRODUCTION OBJECTIVES Filled with exciting close-up images, this video is After viewing this video, students should know: designed to introduce students to the microscope and its incredible world. This remarkable instrument opens lenses magnify because of their curved edges an entirely new world unseen by the eye alone and continues to be the single most important tool used in overall magnification increases when one lens scientific study and medical research. is placed above another The video opens with a discussion of how magnifica- microscopes work by combining lenses tion occurs, and includes a sequence on magnifiers. It is explained that overall magnification can be stereomicroscopes have twin eyepieces and increased by placing one lens above another, and that can be used to examine both solid and is essentially how a microscope works. transparent objects Viewers are then introduced to the stereomicroscope a standard light microscope is much more pow- and its various features and capabilities. The stereomi- erful than a stereomicroscope and is used to croscope can be easily identified by its binocular-style examine thin or transparent objects by illumi- eyepieces. nating them from below Most of the video deals with the far more powerful the lenses on a microscope are referred to as standard light microscope and its features. Student the eyepiece lens and the objective lens light microscopes are about 10 times more powerful than stereomicroscopes, and can usually be identified a variety of pond organisms can be examined by their single eyepiece lens. under the microscope Also included are sections on specimen slides and the you can examine your own cheek cells and gathering of pond water. bacteria from your mouth, under the micro- scope The video concludes with a brief history of the micro- scope leading up to the electron microscope. Antony van Leeuwenhoek was probably the first person to observe bacteria After viewing this video, students should have a basic understanding of what a microscope is and how to use Louis Pasteur was the first person to prove that it. In addition, they should come away with an appre- bacteria caused disease ciation of the microscope's importance in science and medicine. electron microscopes use electrons to magnify instead of light specimen. The narrator then discusses the basics of using a stan- The video opens with a discussion of how a magnify- dard light microscope. Specimens must be very thin so ing glass enables us to see things much larger than that light will pass through them, and some are stained they really are. Viewers are asked how is it that magni- or treated in chemicals so that you can see them more fication occurs. A classroom demonstration shows that easily. They should be placed on the microscope stage a glass globe filled with water causes the text of a beneath the stage clips. They are illuminated from book to appear magnified, due to the curvature of the below using either an illuminator or a mirror. A large globe. While ancient peoples may have used glass focus knob is used to bring a specimen into rough globes, or even crystal balls, to magnify objects, much focus, while a small focus knob is used to bring a spec- more practical as a magnifier is a thick piece of glass imen into fine focus. Centering a specimen can be with curved edges called a lens. Students learn that tricky because the specimen appears to move in the magnifiers come in a variety of styles and magnifica- opposite direction you move it. Some microscopes tions. have a mechanical stage which makes centering easy. Another classroom demonstration shows a student Students are cautioned that a microscope is a delicate placing one magnifier above another to increase the instrument and should be handled with great care. overall magnification. It is explained that that is essen- They should never touch the glass in the lenses, and tially how a microscope works, combining lenses to lenses should only be cleaned if they're dirty, using increase overall magnification. lens cleaner and lens tissue. A microscope should only be carried by its arm and base and, when not being The first microscope featured is the stereomicroscope, used, it should be replaced in its storage case or pro- which usually has a maximum magnification of around tected with a dust cover. 40. This type of microscope can examine both solid and transparent objects. The lenses on a stereomicro- It is discussed that while most student microscopes are scope include two eyepiece lens and an objective lens, set up for brightfield illumination, some might also which is usually adjustable. A stereomicroscope is have darkfield illumination. Both methods have useful focused by turning its focus knob. The video then pre- applications. sents a variety of specimens that can be examined using this type of microscope. The best thing about microscopes is what they can do, and at this point, the video features a variety of fasci- Students then learn that as powerful as a stereomicro- nating specimens set to fast-paced music. scope is, much more powerful is a standard light microscope. Most student standard light microscopes A group of students are then seen collecting water have a single eyepiece lens and several objective lens- samples at a pond. Back in the classroom they place a es located on a rotating turret. Multiple objectives pro- single drop under their microscope and are fascinated vide a variety of magnifications and each magnifica- by the variety of microscopic organisms they tion teaches us something new and different about a encounter, including amoebas, Paramecium, Stentor, Vorticella, Dileptus, Daphnia, planaria and hydras. The narrator observes that we have much in common REVIEW QUESTIONS with these strange organisms because we are all com- posed of cells. A student proves it by scraping the 1. Why do objects appear larger when placed inside of his cheek to examine his own cheek cells. He behind a glass globe? then scrapes material from his teeth to observe bacte- ria. It is then mentioned that during the Middle Ages, Because of the curved surfaces of the globe. millions of people died from bacteria-caused diseases, but because people could not see these organisms, they 2. In addition to glass globes, what other things had no way of knowing they even existed, let alone might ancient peoples have used to magnify were the cause of disease. It was the famous French objects? scientist, Louis Pasteur who first proved the connec- tion between some forms of bacteria and disease. crystal balls. The video concludes with a discussion of the electron What happens when you place one lens on top microscope, an instrument that uses electrons to mag- of another? nify, rather than light. The electron microscope can magnify objects 100 times more than the most power- It increases the overall magnification.. ful light microscope and, with it, scientists are able to learn more about viruses and the diseases they cause. How do microscopes work? By combining lenses. What is the name of the microscope that has binocular eyepieces and can illuminate speci- mens from above and below? A stereomicroscope. What are the names of the two types of lenses found on microscopes? Eyepiece and objective lenses. Why do standard light microscope specimens have to be very thin? So that light will pass through them. 8. How are specimens illuminated on a standard light microscope? 16. What are protozoa? From below with either an illuminator or a rnirror. Organisms consisting of a single cell. 9. How is the large focus knob used? 17. How does an amoeba move? To bring a specimen into rough focus. By sending out streams of cytoplasm called pseudopods. 10. How is the fine focus knob used? 18. What are the short, hairlike structures that To bring a specimen into fine focus. surround many protozoa? 11. Why is centering a specimen difficult with Cilia. many microscopes? 19. How are we similar to pond organisms? Specimens appear to move in the opposite direc- tion they're moved on microscopes without a We all are made up of cells. mechanical stage. 20. Who was probably the first person to observe 12. How should a microscope be carried? bacteria? By its arm and base. Antony van Leeuwenhoek 13. When not being used, where should a micro- 21. Who was the first person to prove the connec- scope be placed? tion between bacteria and disease? In a storage case or protected with a dust cover. Louis Pasteur. 14. What is the name of the type of illumination 22. A light microscope uses light to magnify.