The Microscope

Question 1

A magnifying glass used to magnify an object to a point where it can be seen by the human eye.

Answer 1

The Microscope

Question 2

The science of investigating small objects and structures using such an instrument.

Answer 2

Microscopy

Question 3

Means invisible to the eye unless aided by a microscope.

Answer 3

Microscopic

Question 4

14th century

History of the Microscope

Answer 4

The art of grinding lenses is developed in Italy and spectacles are made to improve eyesight.

Question 5

Where did the art of grinding lenses develop

what was made to improve eyesight

Answer 5

Italy

Spectacles were made to improve eyesight.

Question 6

What was made in 1590

who made it

Answer 6

The first microscope

Dutch lens grinders Hans and Zacharias Janssen

Question 7

how did dutch lens grinders Hans and Zacharias Janssen make the first microscope

Answer 7

Dutch lens grinders Hans and Zacharias Janssenmake the first microscope by placing two lenses in a tub.

Question 8

who studied various object with his microscope in 1667

was his work

Answer 8

Robert Hooke studies various object with his microscope and publishes his results in Micrographia.

Among his work was a description of cork and its ability to float in water.

Question 9

In 1675, who uses a simple microscope with only one lens to look at blood, insects and many other objects.

He was first to describe cells and bacteria, seen throughhis very small microscopes with, for his time, extremely good lenses.

Answer 9

Anton van Leeuwenhoek (Father of Microscopy)

Question 10

who was Anton van Leeuwenhoek

Answer 10

The Father of Microscopy, who used a simple microscope with only one lens to look at blood, insects and many other objects.

He was first to describe cells and bacteria, seen throughhis very small microscopes with, for his time, extremely good lenses.

Question 11

what happenned in the 18th century

what was an important discorvery then

Answer 11

Several technical innovations make microscopes better and easier to handle, which leads to microscopy becoming more and more popular among scientists.

An important discovery is that lenses combining two types of glass could reduce the chromatic effect, with its disturbing halos resulting from differences in refraction of light.

Question 12

what does chromatic effect mean

Answer 12

blur images due to the differences of colors

Question 13

what happened in 1830

Answer 13

Joseph Jackson Lister reduces the problem with spherical aberration by showing that several weak lenses used together at certain distances gave good magnification without blurring the image.

Question 14

Who reduced the problem with the microscope with spherical aberration by showing that several weak lenses used together at certain distances gave good magnificationwithout blurring the image.

when did he do it

Answer 14

Joseph Jackson Lister

1830

Question 15

Three structural parts of the microscope:

Answer 15

1. Head
2. Arm
3. Base

Question 16

It carries the optical parts in the upper part of the microscope

Answer 16

Head

Question 17

It acts as the microscope’s support; it also carries the microscopic illuminators

Answer 17

Base

Question 18

The part that connects the base to the head and the eyepiece tube to the base of the microscope; it gives support to the head and used when carrying the microscope

Answer 18

Arms

Question 19

Usually equipped with 10x lenses. The lenses magnify the intermediate image formed by the objective lens in the optical tube. They also limit the area of visibility.

Answer 19

Eyepiece or oculars

Question 20

prevents scratching of lens by the user’s eyeglass orvice versa

Answer 20

Eyepiece rubbers

Question 21

for differences in eye grading especially for those wearing prescription glasses

Answer 21

Numbers on the eyepiece

Question 22

used to adjust the lateral separation of the oculars for each individual

Answer 22

Interpupillary tube

Question 23

provides a structural site of attachment for the revolving nosepiece.

Answer 23

Arms or neck

Question 24

holds the objectives and allows for easy rotation from one objective to another.

Answer 24

Revolving nosepiece

Question 25

Function of the **Inner knob before the coarse adjustment knob**

Answer 25

Also known as the **coarse tension adjustment knob** 1. **Prevents the stage from going down and losing focus on the specimen** - Clockwise - to tighten - Counterclockwise – to loosen

Question 25

Function of the **Knob/screw at the back of the microscope**

Answer 25

1. **Controls the height limit of the stage** to prevent breakage of glass slides - Clockwise – to tighten the screw - Counterclockwise – to loosen the screw

Question 26

Functions of the **Numbers on the objectives**

Answer 26

refers to the **thickness of the coverslip to be used**;coverslip to be used must be compatible with the objective to be used for microscopic examination

Question 27

what does **FN20** mean

Answer 27

**Field Number (diameter) (ideal) 20mm**

Question 28

**Objectives**

Answer 28

1. Scanner objective (4x) 2. Low Power Objective (10x) 3. High Power Objective (40x) 4. Oil Immersion Objective (100x)

Question 29

a hole on the microscope stage through which the transmitted light fromthe source reaches the stage

Answer 29

**Aperture**

Question 30

**supports the prepared microscope slide** to be reviewed.

Answer 30

**Mechanical stage** ## Footnote Most microscopes have mechanical stage, which make it much easier to manipulate the object beingobserved

Question 31

Function of the **Mechanical stage knob**

Answer 31

also available by turning the knob left and right or backward and forward

Question 32

Function of the **Stage numbers**

Answer 32

**determines the positioning of the cells** under the microscope; **provides the coordinates or location** of important cells

Question 33

Present to keep the slide stationary.

Answer 33

**Stage clip**

Question 34

**focuses or directs the available light** into the objective as it raised or lowered.

Answer 34

**Condenser** ## Footnote **Lowering** the condenser will **increase the contrast of unstained specimens**.

Question 35

used to focus with the low power objective only.

Answer 35

**Course Adjusment Knob**

Question 35

must be the same with the magnification of the objective for better viewing of the specimen details

Answer 35

**Condenser numbers**

Question 36

**regulates the amount of light** that strikes the object being viewed. May be adjusted by a movable lever

Answer 36

**Iris Diaphragm**

Question 37

Located within the base. For adjustment of the illumination for brightness

Answer 37

**Brightness adjustment knob/Microscopic illuminator**

Question 37

gives a **sharper image** after the object is brought into view with coarse adjustment

Answer 37

**Fine Adjustment Knob**

Question 38

a firm, horseshoe-shaped foot on which the microscope rests’it contains the light or mirror

Answer 38

**Base**

Question 39

**Remember!** Working distance is the distance between the objective andthe slide when objective is sharp focus.

Answer 39

The **higher the magnification** of the objective the **shorter the working distance** will be. **Coarse adjustment** should **not be used** when using **higher magnifications**.

Question 40

Types of Microscope

Answer 40

1.**Compound/Upright** 2.**Inverted** 3.**Stereomicroscope**

Question 41

Objective lens faces **downward**, and specimens is observed from **above**

Answer 41

**Compound/Upright**

Question 42

Suitable for observation of **glass slides or prepared slides**

Answer 42

**Compound/Upright**

Question 43

Objective lens faces **upwards**, and specimen is observed from **below**

Answer 43

**Inverted**

Question 44

Used for routine microscopic examinations

Answer 44

**Compound/Upright**

Question 45

Used for **observation of culture** container (stem cells/unstained cells)

Answer 45

**Inverted**

Question 46

Utilized more on Microbiology

Answer 46

**Inverted**

Question 47

**2 separate light path**, enables observation of specimen from different angles at both eyes

Answer 47

**Steromicroscope**

Question 48

Allows **3D observation** of sample

Answer 48

**Stereomicroscope**

Question 49

Suitable for **animal works** and **large sample imaging**

Answer 49

**Stereomicroscope**

Question 49

Applications of the Microscope

Answer 49

1. Bright Field Microscopy 2. Dark Field Microscopy 3. Phase Contrast Micoscopy 4. Electron Microscopy - TransmissionElectronMicroscope (TEM) - Scanning Electron Microscope(SEM)

Question 49

Bright Field Microscopy ## Footnote Preferred Slides

Answer 49

* The **simplest** of all the optical microscopy illumination techniques * Specimen’s image appears **dark against a bright background** * Light source is usually **tungsten lamp** * Generally used with **compound microscopes** ## Footnote Stained Slides

Question 50

Ability to distinguish between two adjacent points ## Footnote Depends on two factors

Answer 50

**Revolving Power** ## Footnote White light & Numerical aperture

Question 51

Composed of a mixture of colored lights of various wavelengths

Answer 51

White light

Question 52

Expression relating to the cone of light that is delivered to the specimen by the condenser and gathered by the objective

Answer 52

**Numerical Aperture**

Question 53

the ocular magnification multiplied by the objective magnification

Answer 53

**Total Magnification**

Question 54

**Phase Contrast Microscopy**

Answer 54

Uses a **special optic system** which converts differences in phases into differences in intensity such that some structures appear darker than the others ## Footnote Reveals the gross details of the internal structures in a living cell Uses only unstained slides

Question 55

**Darkfield Microscopy**

Answer 55

* Objects appear brilliantly illuminated against a black background

Question 56

Used to **demonstrate spirochetes** which are **difficult to observe** in **transmitted light**

Answer 56

**Darkfield Microscopy**

Question 57

Develops an image resulting from variable electron density of the specimen interposed in the electron beam | Electron Microscopy

Answer 57

Transmission Electron Microscope (TEM)

Question 58

Develops an image resulting from variable electron density of the specimen interposed in the electron beam | Electron Microscopy

Answer 58

Transmission Electron Microscopy

Question 59

Resolving power is 0.001 um, which is 200X that of light microscopes | Electron Microscopy

Answer 59

Transmission Electron Microscope (TEM)

Question 60

* Specimens must be fixed, stained and dried * Used to observe internal ultra-structural detail of cells and observations of viruses or small bacteria

Answer 60

Transmission Electron Microscopy (TEM)

Question 61

Has a practical limit of resolution of 0.005um or five-fold less than that of TEM | Electron Microscopy

Answer 61

**Scanning Electron Miscroscope (SEM)** ## Footnote It has more details on the surface (outside details)

Question 62

Produces monotone, tri-dimensional image by detection at a 90degrees angle of secondary electrons emitted from the specimensurface as a result of bombardment by the primary electron beam

Answer 62

**Scanning Electron Microscope (SEM)**

Question 63

Located too close to mechanical appliances or machinery that can cause external vibrations | Consequence ## Footnote Treatment

Answer 63

Blurred image because of vibrations ## Footnote * Remove the microscope from the source of vibration * Use a strudy table as a support or use a vibration proof table

Question 64

Microscope is located near a window | Consequence ## Footnote Treament

Answer 64

Bright light from the window prevents correct focusing ## Footnote * Set up the microscope near a wall * Position the microscope in such a way that the overhead light falls slightly in front of the microscope

Question 65

A place where the room light enters the eyepiece | Consequence ## Footnote Treatment

Answer 65

Room light or flares are reproduced on the photo ## Footnote * Cover the eyepiece with caps * Shut out stray light getting into the eyepiece or the focusing telescope by changing the optical path selector

Question 66

A dusty and dirty room; placed near window where the dust can enter from the outside | Consequence ## Footnote Treatment

Answer 66

Black spots are reproduced on the specimen image ## Footnote * Set up the microscope in another room * Cover the whole microscope with a dust proof covering

Question 67

Possible causes of **no light**

Answer 67

* Power cord is not connected, power switch is off * Wrong bulb is installed * The bulb has burnt out * Light intensity control is turned down too low * Objective is not properly in position * If using the 100x objective immersion oil has not been applied

Question 68

Possible causes of **Image is too dark**

Answer 68

* Increase light intensity * Sub-stage iris diaphragm is not open enough * Condenser is too low

Question 69

Possible causes of **image is too light**

Answer 69

* Decrease light intensity * Sub-stage iris diaphragm is open too much

Question 70

Possible causes of **spot in the field of view that doesn’t move when the slide is moved**

Answer 70

Lens is dirty. Clean both the objective and eyepiece.

Question 71

Possible causes of **poor image quality, poor resolution, image not sharp (100x oil objective)**

Answer 71

* Clean objective, eyepiece and condenser. * Check if immersion oil is contaminated or cloudy or air bubbles are present. * Slide is wrong way up.

Question 72

Possible causes of **poor image quality, poor resolution, image not sharp (40x objective)**

Answer 72

There is dirt or oil on the lens

Question 73

Possible causes of **Uneven illumination**

Answer 73

* Adjust condenser * Make sure objective has clicked into place

Question 74

Possible causes of **Flickering light**

Answer 74

* Bulb needs replacement * Loose connection at the outlet * Bulb not properly inserted * Check voltage supply

Question 75

Possible causes of **Half the viewing field is illuminated**

Answer 75

Make sure the objective is clicked into place

Question 76

Possible causes of **Unable to focus the slide**

Answer 76

* Coverslip is too thick * Slide is the wrong way up * The stage is slowly dropping, adjust tension of coarse adjustment knob * Clean the slide, objective and eyepiece

Question 77

First step in **Microscope Handling and Storage**

Answer 77

When work is completed, **lower the stage**, **remove the slide**, rotate in the **lowest power objective**, **wrap the cord** loosely around the base and **cover with a dust cover**. Take care not to wrap the cord around a hot(built in) light source

Question 78

Step two in **Microscope Handling and Storage**

Answer 78

Always **keep your microscope covered** when not in use. **Optics and mechanical parts** must be **protected from dust**.

Question 79

Step three in **Microscope Handling and Storage**

Answer 79

Always move the microscope with **one hand under the base** and the **other hand gripping the arm or frame**.

Question 80

Step four of **Microscope Handling and Storage**

Answer 80

Keep microscopes **away from vibration**, **moisture**, **high temperatures** and **direct sunlight**.

Question 81

Step five of **Microscope Handling and Storage**

Answer 81

**Never store** microscopes in **chemical storage areas** as corrosive fumes may **damage metal and lenses**.

Question 82

Step one in **Microscope Maintenance**

Answer 82

**Treat lenses with great care** as they can be easily scratched. **Never use anything abrasive**.

Question 83

Step two of **Microscope Maintenanace**

Answer 83

When cleaning lenses, **first blow away any dust with a blower brush** then **use lens tissue and lens cleaning fluid to clean the objectives and eyepieces**. Do not use paper towel or regular tissues, as they willscratch the lens. Do not use other solvents.

Question 84

Step three of **Microscope Maintenance**

Answer 84

**Do not remove eyepieces or objectives** from their location but **clean only their external surfaces**.

Question 85

Step four of **Microscope Maintenance**

Answer 85

**Remove immersion oil from the 100x objective** immediately after use with lens tissue and lens cleaning fluid.

Question 86

Step five of **Microscope Maintenance**

Answer 86

**Wipe dust off the body** of the microscope with a **damp cloth**

Question 87

Step six of **Microscope Maintenance**

Answer 87

**Never attempt to take a microscope apart**. This could impair operation,efficiency and accuracy.

Question 88

Step seven of **Microscope Maintenance**

Answer 88

**Have the microscope serviced regularly by a professional**, as most microscopes require periodic lubricating and minor adjustment of their mechanical parts.

Question 89

Step eight of **Microscope Maintenance**

Answer 89

Follow your user’s manual for instruction in replacing the bulb. Always **allow a bulb to cool before replacing it**. When replacing bulbs **avoid touching the glass with your hands**, use a tissue. Fingerprints can **reduce bulb quality and reduce its life**.