01.2 Microscopes - AI Flashcards
What are microscopes?
Scientific instruments used to visualise objects too small to see with the unaided eye.
What does microscopic mean?
Describes something too small to be seen by the unaided eye.
What is microscopy?
The science of investigating using a microscope.
When did the earliest compound lens light microscope appear?
Around 1620 in Europe.
Who was the first to publish findings on the use of the microscope?
Robert Hooke in 1665 in Micrographia.
What did Robert Hooke observe with the microscope?
The cell wall, and he did not believe they were alive.
Who observed motile objects termed ‘animalcules’?
Anton van Leeuwenhoek in 1676.
What are light microscopes used for?
To view living specimens in natural colour.
How do light microscopes magnify images?
By bending light using lenses, with a magnification factor of roughly 100-fold.
What chemical methods can enhance light microscopy?
Chemical dyes and fluorescent labeling.
What is the equation for calculating magnification with a light microscope?
Magnification = Objective lens x Eyepiece (ocular) lens.
Calculate the magnification if the objective lens is 4x and the eyepiece is 10x.
40x.
What is the equation for calculating magnification from an image?
Magnification = Image size ÷ Actual size.
How do you calculate actual size from a magnified specimen?
Actual Size = Image size ÷ Magnification.
What do electron microscopes use to focus electrons?
Electromagnets.
What are the advantages of electron microscopes over light microscopes?
Significantly greater magnifications and resolutions.
What type of specimens can be viewed with electron microscopes?
Dead specimens in monochrome.
When were electron microscopes first used?
In 1931.
What is a transmission electron microscope (TEM) used for?
To pass electrons through a specimen to generate a cross-section.
What is the maximum magnification of a TEM?
Up to 100,000x.
What is required for specimen preparation in a TEM?
The specimen needs to be sliced very thinly and placed in a vacuum.
What do scanning electron microscopes (SEM) do?
Scatter electrons over a surface to differentiate depth and map in 3D.
What is the magnification range of SEM?
From 15x to 200,000x.
What type of radiation do SEMs use?
Electromagnets rather than lenses.
What is a requirement for preparing samples for SEM?
Removing all water from the specimen or freezing it.
What is the resolution quality of SEM?
Very good resolution.
What is a common challenge in preparing specimens for TEM?
Time-consuming preparation and risk of destroying the sample.
Fill in the blank: The bar length of the scalebar is ______.
100 nm.
