Introduction to the “Nanoworld
3.1.10 Unifying Themes
D. Apply scale as a way of relating concepts and ideas to one another by some measure.
* Apply dimensional analysis and scale as a ratio.
* Convert one scale to another.
E. Describe patterns of change in nature, physical and man made systems.
* Describe how science and tech concepts are used to solve practical problems (e.g., momentum, gravity, tectonics, cell theory, evolutionary theory, atomic theory, theory of relativity, germ theory, heliocent-rism, gas laws).
3.2.10 Inquiry and Design
A. Apply knowledge and understanding about the nature of scientific and technological knowledge.
* Compare and contrast scientific theories and beliefs.
* Know that science uses both direct and indirect observation means to study the world and the universe.
* Integrate new information into existing theories and explain implied results.
3.3.10 Biological Sciences
* Explain the structural and functional similarities and differences found among living things.
* Identify and characterize major life forms according to their placement in existing classification groups.
* Explain the relationship between structure and function at the molecular and cellular levels.
There is a common belief that parallel worlds are coexisting with, but unaware of each other….
The truth is there are “dimensions” that coexist, but WE are not aware of at least one –this dimension “very small” -and the different laws that govern that dimension (such as the relatively absence “law of gravity.” That truth maybe expressed by the introduction of a brilliant television show from the “early years” of television when everything was see in black and white. This show was called the Twilight Zone. (http://www.youtube.com/watch?v=bhKiqo-nqm0&feature=related)
These, very real parallel worlds are a matter of size. While you might be aware of an ant on the sidewalk, is this ant aware of you? If an ant were able to “see” the same way as we do, could it observe at nanoscale level (one nanometer is 10 hydrogen atoms side by side).
While you might be aware of the sun and the stars, you think they are aware of you? In nanotechnology we enter a world of size so small, in which we cannot see individual atoms, but using special devices we can “see” and even move atoms into two dimensional shapes, such as this famous electron microscope photo revels. The atoms are in “false color”, as when we use electrons to see, a black and white image is produced. Color is added at the discretion of the individual to enhance the information in the photograph.
This IBM logo was done using an STM. (A Scanning Tunneling Microscope is a powerful tool for viewing surfaces at the atomic level.) For STM, good resolution is considered to be 0.1 nm lateral resolution and 0.01 nm depth resolution. (Ensure students understand “resolution vs. magnification, using low and high resolution photographs.)
(At this point do one-“billionth” dilution experiment with water, food color, 9 small paper cups per group, and plastic 1 mL pipettes).
Engage the students with estimating how big a container would be needed to hold a billion grains of salt. (Bathtub would be the right container).
Present following dilution chart on lab worksheet to class for group lab:
10 test tubes and racks or white paper cups per student group.
1 mL pipettes
Other material, such as paper towels as required.
Have the students’ use 0.1 and 0.01 nm and express the numbers using words (1/10th and 1/100th nanometers) so they “see” how SEM can observe individual atoms.
Transmission electron microscopy (TEM) is a microscopy technique whereby a beam of electrons is transmitted through an ultra thin specimen, interacting with the specimen as it passes through it. An image is formed from the electrons transmitted through the specimen, magnified and focused by an objective lens and appears on an imaging screen, a fluorescent screen in most TEMs, plus a monitor, or on a layer of photographic film.
Play the video, Powers of 10, that helps explain the relative order of sizes. Point out to the students there are nanometer sized, self-organized molecules that can have a major impact on living organisms.
One example are the phages, which “prey” on specific cells. HIV is an example of the “bad” phages, which attack the T4 cell vital to our immune system. Other phages, such as a T2 attack bacteria like Escherichia coli (E. coli) and have been used for over 60 years as an alternative to antibiotics.
These “good” phages are seen as a possible therapy against multi-drug resistant strains of many bacteria in medical therapies. Bacteriophages are much smaller than the bacteria they destroy - usually between 20 and 200 nm in size.
(Homework: sent students home with strip [roll] of paper lined every meter [for nine meters], representing powers of ten, a package of small pictures of various objects that would fit on the strip of paper with pictures to be placed on the strip in the appropriate places, and some sort of fastening device that the could use securely fasten said pictures.)