Unit 4 Section 1: Introduction to Microscopes

​Science Root of the Day:

DO NOW: Write what you think the example words mean in your lab manual.

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Introduction to Microscopes

Lesson Objectives

• Describe the History of Microscopes and how they work

• Identify the parts of a microscope

• Understand Proper Microscope Usage

What is a Microscope?

• Microscope: a laboratory instrument used to view objects too small to be seen with the naked eye

  • Micro=small Scope= to look at

  • Are many different types depending on what you want to look at

• Microscopy: the science of observing small objects

Lens History

• Early Humans used small crystals to help focus light

  • Could aid in vision and help start fires

• Ancient Egyptians and Mesopotamians would polish quartz rock to make lenses

  • Nimrud Lens: a piece found in Assyria from between 750 and 710 BC

Microscopy History

• 13^th Century: Italian Glass blowers created early eyeglasses

  • Each lens built to bend light to a specific spot

  • Set the stage for lenses to be used in vision aids

    • Telescopes, Microscopes, hand lenses, etc

Early Microscopes

• 1590's: The first microscopes developed in the Netherlands

  • Two rival inventors came up with the idea, and no one is sure who the true inventor is due to claims of one stealing the others design

  • Early design only had 3x Magnificaation

• Galileo refined the design in 1609 to create a microscope with a magnification of 30x

The Father of Microscopes

• Anton Van Leeuwenhoek

  • Born in 1634

  • A thread maker who began working with lenses to get a better view of threads

  • would melt glass rods to form smaller lenses, which gave the best magnification

    • His compound microscope design could magnify up to 200x, far better than Galileo's design

  • tested his design by looking at water samples, and discovered microbial lifeforms

  • Is known as the father of the microscopy

Multiple Choice

True or false: Galileo invented the first microscope

• True

• False

Multiple Choice

A microscope is an instrument that.

• makes faraway objects look closer.

• makes small objects appear larger.

• decreases the size of small objects.

• increases the size of small objects.

Multiple Choice

True or false: the earliest lenses were made of glass

• True

• False

How does a Microscope Work?

• In class, we will be using a compound light microscope

  • It uses a light source and mirrors to direct light through lenses to the eye

  • The compound has two lenses, one at the bottom and one at the top by the eyes

    • Both affect the magnification

​Microscope Parts-Arm

• Arm: The support structure of the microscope

  • Has a different size and shape depending on the type of microscope

  • Always carry a microscope with one hand around the arm and the other supporting the bottom

​Microscope Parts-Stage & Diaphragm

• ​Stage: Where you place whatever specimen you are looking at

  • Mainly slides, but could also be Petri plates

• ​Diaphragm: Controls the amount of light let in

  • In General, you will not worry about it in this class

​Microscope Parts-Adjustment Knobs

• ​Coarse Adjustment Knob: Allows for major changes in the stage location

  • ONLY USE WITH THE LOWEST OBJECTIVE LENS

  • Is larger

• ​Fine Adjustment Knob: Allows for smaller changes in the stage location

  • Is smaller

• Sometimes both knobs are connected but are sometimes two separate pieces

​Microscope Parts- Ocular Lens

• ​Ocular Lens: Part of the microscope you see through, Can not be changed

  • Generally has a magnification of 10x, but some are stronger

    • Always check the magnification before you start

​Microscope Parts-Objective Lenses

• ​Objective Lenses: The set of second lenses that can be switched to change magnification

  • When using, always start with the smallest lens size to avoid breaking the slide or microscope

  • Are on a rotating nosepiece

  • Total Magnification= occular * Objective

    • If ocular is 10, and objective is 20,

      • total= 10 * 20=200

Multiple Choice

In Class we will use

• An electron Microscope

• A compound Microscope

• A single lens Microscope

• A hand lens

Multiple Choice

This part of the microscope can be adjusted to change the amount of light on the sample

• Ocular Lens

• Stage

• Diaphragm

• Objetive Lens

Multiple Choice

A microscope has a 4x ocular lens and a 10x objective, what is this microscope's total magnification?

• 4x

• 14x

• 40x

• 400x

Multiple Choice

You must carry a microscope with...

• your nose in the air like you just don't care

• your hand and your chin

• two hands, one under the base and one on the top

• two hands around the arm

• two hands under the base

Multiple Choice

To focus a specimen, it is best to start with which objective lense

• The high power

• the lowest power

• The medium power

• The ocular

Multiple Choice

What term refers to the ability to distinguish between two objects in a microscope?

• Resolution

• Contrast

• Magnification

• Illumination

Multiple Select

Which type of microscope uses electron beams to visualize images?

• Transmission Electron Microscope (TEM)

• Phase-contrast microscope

• Brightfield light microscope

• Scanning Electron Microscope (SEM)

Multiple Choice

What is the function of the coarse focus knob on a microscope?

• Move the stage up or down dramatically

• Adjust the light level

• Center the image

• Fine-tune focus

Multiple Choice

What should be used to clean the lens of a microscope?

• Regular tissue

• Microfiber cloth

• Lens paper

• Wet wipes

Multiple Choice

Number 8

• Base

• Stage

• Tube

• Arm

Multiple Choice

Number 12

• Coarse Adjustment

• Fine Adjustment

• Small Adjuster

• Large Adjuster

Labelling

Label the parts of the Microscope

Drag labels to their correct position on the image

Occular Lens

Arm

Stage

Coarse Adjustment Knob