Microscopes

• How do you convert between millimetres to micrometres?

  Multiply by 1000.
• what is the formula that links magnification, image size, and object size?

  Magnification = image size ÷ object size
• how do you convert micrometres into nanometres ?

  multiply by 1000
• how do you convert milimetres into micrometres?

  divide by 1000
• how do you conver milimetres into nanometre?

  divide by 1000000
• what is resolution?

  In microscopes, resolution is how well a microscope can distinguish between two points that ar close together
• what is magnification?

  How many times bigger the image of a specimen obeserved is in comparison to the actual size of the specimen.
• How do light microscopes work?

  By passing a light through a specimen and focusing the light on an eyepiece which magnifies the image.
• How do laser scanning confocal microscopes work?

  A laser beam is focused through a lens which is aimed at a beam splitter.

  The beam splitter splits the beam and some of the light is directed onto the specimen.

  WHen the laser hits the dyes it causes them to give off fluorescent light, which is focused into a pinhole onto a detector.

  The detector is connected to a computer which creates an image.
• What does the pinhole do in a laser scanning confocal microscope?

  It blocks out any out of focus light
• Why are laser scanning confocal microcopes good?

  They can be used to look at objects at different depths in thicker specimens. Multiple images can be produced by the microscope and combined into a 3D image.
• how do transmisson electron microscopes (TEMs) work?

  TEMs use electromagnets to focus a beam of electrons, which is then transmitted through the specimen to produce 2D images. Denser parts of the specimen absorb more electrons thus making them look darker in the image.
• Why are Transmission electron microscopes (TEMs) good?

  TEMs are good because they provide high resolution images, they can be used to look at very small organelles and their internal structures.
• What is the biggest problem with Transmission electron microscopes?

  The sample must be thinly sliced, and the angle at which they are sliced can impact how they appear.
• How do scanning electron microscopes (SEMs) work?

  SEMs scan a beam of electrons across the specimen. This knocks off electrons from the specimen, which are gathered in a cathode ray tube to form an image. The images produced show the surgace of the specimen and can be 3D however their resolution in images is lower than transmission electron microscopes.
• Why are specimens that are used in electron microscopes treated with heavy metals?

  This is to scatter electrons that are fired at the sample, this gives a higher contrast between different structures.
• What is the maximum resolution of a light microscope?

  0.2 micrometers
• What is the maximum resolution of a transmission electron microscope?

  0.2 nanometres
• what is the maximum resolution of a scanning electron microscope?

  2 nanometers
• What is the maximum amount of magnification in a light microscope?

  1500 x
• what is the maximum amount of magnification of a transmission electron microscope?

  it can go above 1000000 x
• What is the maximum magnification in a scanning electron microscope?

  500,000x