B. explore a 440 nm dot
A related exploration problem might involve this zoomable image of a specimen-region smaller in area than a blu-ray laser-disc spot. A closeup from that larger image (zoomed-in field-width only about 45 nm) is marked up at right to help you get a sense of what to look for. Your strategy might for example be to: Systematically explore the image field by panning around after zooming in, and take notes as you are doing it on the Platinum (Pt) particles and carbon nanotubes that you manage to locate.
Notice from the marked-up image at right that Pt particles are darker and often have tiny stripes on them.
The first question, how many Pt particles can you find in the image which are over a hole in the carbon support film (seen at right in the marked up image)?
Next, assume that the width of the starting image field (digitized from a TEM negative taken at 240kx) is 440 nanometers i.e. about the wavelength of blue light and one tenth of the width of a single red-blood cell.
The second question is, what is the average size of the Pt particles that you found?
Other questions to explore might include:
What do you get for the average-spacing between adjacent walls (i.e. graphene layers) in a multi-wall carbon nanotube?
What do you estimate for the observable spacing between lattice planes (i.e. stripes) in some of the Pt particles?
What would you estimate for the thickness of the carbon support film in the image?
What does this image (and power spectra of it) have to say about the contrast transfer function of the microscope used to record the image?
What does the "noise level" on the film in regions with no specimen tell us about the minimum-size proton-cluster detectable on, and/or adjacent to, a single-walled carbon nanotube support?
and what else?
Other zoomable images
nano particles
self-combusting Nb?/nano-iron/holey-C: 240kx@2400dpi
mystery particle set #7609/holey-C: 240kx@2400dpi
nano-gold on unholey-C: 240kx@2400dpi; FW~1791Å~4062px
tubes, catalysts, sugar phosphate polymers and films
single wall carbon nanotube before breaking
the same SWNT after breaking: 240kx@2400dpi
Pt/ssDNA/SWNT/holey-C: 240kx@2400dpi
defects in large (self-supporting disk) crystals
raspberry HREM 1: 240kx2400dpi
raspberry HREM2: 240kx@2400dpi
buried interface?: 240kx@2400dpi
red giant starsmoke after ultramicrotomy
closeup of jack the bean: 240kx@2400dpi
unlayered graphene from onion core: 240kx@2400dpi
Notice also from the marked-up image that carbon nanotubes show up as even numbers of uniformly-spaced parallel lines in the image, i.e. a single-walled nanotube has two lines separated by the tube diameter, a double-walled nanotube has 4 lines, etc. The third question is, how many "relatively clean" carbon nanotubes with between one and three atom-thick walls can you clearly identify in the image? What fraction of those can you say appear to have "single-strand DNA curlicues" wrapped around them?
The fourth question is, what is the average diameter of the nanotubes that you managed to identify?
In the days ahead, we may add reporting space up here for you to tell us what you found. In the meantime, however, this empirical observation exercise is already being explored as an activity for use e.g. on take-home tests.
