Pigments added to specimens that absorb light at specific wavelengths in order to create contrast.

Chromophores

Phosphorescence is when photons are absorbed, and then emitted later on. 

Phosphorescence

Fluorescent dyes can absorb UV or blue light to emit different colors of visible light. 

Fluorescent Dyes

Due to refraction, different electromagnetic radiation waves can be changed into a wavelength on the visible light spectrum, allowing humans to see it. 

Electromagnetic Radiation (EMR)

Methods of preparation to allow us to view and distinguish different cells and their structures that were otherwise translucent through the use of ionic salts in stains/dyes. 

Staining 

Because microbes are small and translucent, we need to utilize other techniques to visualize the different structures, even under high levels of magnification and resolution.

Microbes are too small to be seen with the naked eye, so humans have developed techniques and technology to observe and study them.

Visualizing Microbes

https://openstax.org/details/books/microbiology/

Microbiology covers the scope and sequence requirements for a single-semester microbiology course for non-majors. The book presents the core concepts of microbiology with a focus on applications for careers in allied health. The pedagogical features of the text make the material interesting and accessible while maintaining the career-application focus and scientific rigor inherent in the subject matter. Microbiology’s art program enhances students’ understanding of concepts through clear and effective illustrations, diagrams, and photographs.

Microbiology is produced through a collaborative publishing agreement between OpenStax and the American Society for Microbiology Press. The book aligns with the curriculum guidelines of the American Society for Microbiology.

OpenStax Microbiology Textbook

Convex lenses are used to magnify images; Concave lenses redirect light. 

Lenses 

Creating Contrast

How we perceive light depends on how it is reflected, refracted, and absorbed or transmitted through a material medium.


Light Perception

Microscopes allow us to magnify and view microscopic specimens. Before microscopes, theories about microorganisms were strictly hypothetical.

Microscopes

There are two ways to prepare specimens for light microscopy:
- wet mount 
- fixation

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