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A Hydrothermal worm under an electron-microscope! What else is all around us that is too small to see with just our eyes?
Ever since Robert Hooke first made his beautiful sketches of magnified insects, scientists have been peering at the world through microscopes.
The microscopic world generally refers to things humans can't see with the naked eye. But thanks to microscopes, scientists have the tools to visualize the detailed structures and dynamic processes inside very small things from living cells to the structure of atoms themselves.
Modern microscopes come in three flavors: optical microscopes, electron microscopes and scanning probe microscopes.
Within optical microscopes, there are wide-field microscopes and confocal microscopes. Wide-field scopes include your basic light microscope, which has a lens or lenses to magnify visible light transmitted or reflected by a sample. They're good for looking at single layers of cells or thin tissues, Piston said.
The main advantage of optical microscopes is their ability to image living cells. But they are limited to a resolution of about 200 nanometers, where one nanometer is a billionth of a meter; for comparison, a sheet of paper is 100,000 nanometers thick.
To see finer details, scientists employ electron microscopes, which produce images using a beam of electrons instead of light. These have much better resolution than optical microscopes, because the wavelength of electrons is about 100,000 times shorter than visible light. However, this type of microscope can't reveal living cells, because the preparation steps or high-energy electron beams kill them.
Floating & Sinking Task (you can get materials in GATE classroom if you do not have them at home)
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