18. Transmission Electron Microscope (TEM) Beams of light are passed through a thinly sliced specimen. • Magnify up to a million times • Reveal the detailed structures inside cells • Produce 2D images. Image: University of Melbourne
20. Scanning Electron Microscope (SEM) A beam of electrons move across a specimen and constructs an image showing details of its surface. • Produces 3D images • For high resolution surface topographical study of mainly biological specimens. Image: University of Melbourne
21. SEM Images Images: The Bugscope Project, Beckman Institute, University of Illinois at Urbana-Champaign. http://bugscope.beckman.uiuc.edu/ Bee eyeball Edge of mosquito wing Hairs on a fly
24. Synchrotron A synchrotron is a large machine (about the size of a football field) that accelerates electrons to almost the speed of light. As the electrons are deflected through magnetic fields they create extremely bright light. The light is channelled down beam lines to experimental workstations where it is used for research. It can be used to study the shape of molecules and proteins There is an Australian synchrotron in Melbourne.
25. Other Ways of Measuring We can also measure things with light… Diffraction of light can be used to determine the size of particles or the size of the spaces between because particles can make light bend (diffract) around them. The colors seen in a spider web are partially due to diffraction . Image: John Haslam @ flickr
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Notas do Editor
Scale & Measurement module - Title Page
USA uses imperial measurements – probably because it is too expensive to convert Britain uses inches and miles for distances Point out that the correct Australian spelling is METRE. USA uses METER
Common examples of these prefixes are Gigalitres – water reservoirs Megalitres – swimming pools Micrometres – measuring cells under the microscope Nanometres – size of large molecules Emphasize the correct use of prefixes – ML and mL are very different μ m – discuss the use of Greek alphabet in scientific work
Using the cards is important to develop this difficult concept of scale Using the smallest sizes on the left will ensure the number line is the same as used in mathematics. Using the largest sizes on the left will allow easier conversions as the decimal point will move in the same direction All students will probably have only been exposed to linear scales before this task. Emphasize this is a logarithmic scale where each item is 10 times bigger than the previous one.
Video at http://www.micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/index.html
You Tube clip of longest fingernails at - http://au.youtube.com/watch?v=8HuKB1drzbg It would take around 24 years to grow nails to 76cm long
Clip can be seen at http://aunet.com.au/stereo_microscope.htm
If you need some light revision, here are some optional research questions, and a fact sheet is provided
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