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The Invisible World

The Invisible World. Imagine what we would know about the world if we could see things that the human eye can't see?. Outline. Electron microscopes Synchrotron Viruses/Vaccines. Metric Conversions. T _ _ G _ _ M _ _ K h de UNIT d c m _ _ µ _ _ n _ _ p.

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The Invisible World

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  1. The Invisible World Imagine what we would know about the world if we could see things that the human eye can't see?

  2. Outline • Electron microscopes • Synchrotron • Viruses/Vaccines

  3. Metric Conversions T _ _ G _ _ M _ _ K h de UNIT d c m _ _ µ _ _ n _ _ p

  4. What is the smallest thing we can see with the naked eye? • The closest a human eye can focus on is about 20cm. We cannot see anything under 0.05mm or 50 µm. As a typical animal cell is only about 10 µm, we didn't understand the existence of the basic building block of life until the invention of the microscope.

  5. The big invention that put the very small on the map • The first person to use a microscope was Robert Hooke. He was a famous scientist during the 17th century.

  6. How small can you see? • The absolute limit for observation of an ordinary microscope is set by the wavelength of light. About the smallest thing that can be seen is about 200nm or 200 x 10-9m. • Light waves just move past such a small obstacle without being affected. • This means that a light microscope can never magnify more than about x1000. To get more usable magnification than this we need to use shorter wavelengths.

  7. That's where the electron microscope comes in! • Electron microscopes use beams of electrons. • If you take an electron and accelerate it up to close to the speed of light, it has a wavelength about the same as an x-ray. This is about a million times shorter than visible light so you can see about a million times more detail.

  8. How does an electron microscope work? • Fast moving electrons are bent and focused using magnetic lenses. • The picture is seen on a fluorescent screen where the electrons give up some of their energy as light. • An example of an electron microscope is the synchrotron

  9. Synchrotron

  10. What can we see with the most powerful microscopes today?

  11. Mosquito Head

  12. Mascara Brush

  13. Toilet Paper

  14. Hypodermic Needle

  15. Human Blood

  16. Cat Flee

  17. Velcro

  18. Leaf Vein

  19. Porcupine Quill

  20. Dentist Drill

  21. Chicken pox

  22. Eczema Herpeticum

  23. Herpes

  24. Viruses • Can’t be seen with the human eye • Can be either plant, animal or bacterial • Made of a nucleic acid core (RNA or DNA) surrounded by a capsid • May also be enclosed in an envelope • Direct production of viral proteins in host cell once infected • Infections vary in severity • Can damage or destroy host cells in effort to reproduce

  25. Key Words

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