Science 8 Video Notes

The Incredible World of the Microscope

  1. Recall optics: what kind of lens is used for magnification?

Convex lenses are magnifying lenses.

  1. When a 3x magnifying lens and another 3x magnifying lens are used together, what is the overall magnification? 3 x 3 = 9
  1. What are the two lenses in a microscope? The eyepiece and the objective lenses
  1. How are microscopes focused? By turning the focusing knobs
  1. How are the objective lenses changed on a standard student light microscope? You turn the rotating turret.
  1. What is the greatest magnification on a typical student microscope? The greatest is 40x 10 = 400
  1. What new detail can you see on a brine shrimp at 100x? You can see the eggs
  1. What are specimen slides? Very thin slices of material on a glass slide
  1. How should you hold a glass slide? Carefully, by the edges
  1. Why should you keep both eyes open? So they don’t get tired
  1. Why are there two focus knobs? The coarse focus knob moves the stage quickly and the fine focus moves it a smaller amount
  1. Why should you never touch the glass of a lens? Your fingerprints can damage the lens.
  1. How should you carry a microscope? With TWO hands – one on the arm and one under the base
  1. Describe 3 organisms found in pond water. Parameciumlike a grain of rice, eats algae

Hydra looks like an anemone

Daphnia (water flea) like a clear flea

Amoeba “ The blob” moves with pseudopods

  1. Describe what can be found when you scrape your cheek? Ick. Cells and bacteria.
  1. How are specimens prepared for the electron microscope? They’re gold-plated to reflect electrons
  1. How is an electron microscope different from a light microscope? (two ways) It magnifies much more than a light microscope, uses electrons instead of light