3.3: Microscopic measurements and calculations

Question 1

When using a light microscope, we can measure the size of objects using what?

Answer 1

When using a light microscope, we can measure the size of objects using an eyepiece graticule

Question 2

When using a light microscope, we can measure the size of objects using an eyepiece graticule.
What is an eyepiece graticule?

Answer 2

An eyepiece graticule is a glass disc that is placed in the eyepiece of a microscope

Question 3

When using a light microscope, we can measure the size of objects using an eyepiece graticule.
An eyepiece graticule is a glass disc that is placed in the eyepiece of a microscope.
What is etched on to the glass disc?

Answer 3

A scale is etched on to the glass disc

Question 4

When using a light microscope, we can measure the size of objects using an eyepiece graticule.
An eyepiece graticule is a glass disc that is placed in the eyepiece of a microscope.
A scale is etched on to the glass disc.
This scale is typically how long?

Answer 4

This scale is typically 10 mm long

Question 5

When using a light microscope, we can measure the size of objects using an eyepiece graticule.
An eyepiece graticule is a glass disc that is placed in the eyepiece of a microscope.
A scale is etched on to the glass disc.
This scale is typically 10 mm long and is divided into what?

Answer 5

This scale is typically 10 mm long and is divided into 100 sub-divisions

Question 6

When using a light microscope, we can measure the size of objects using an eyepiece graticule.
An eyepiece graticule is a glass disc that is placed in the eyepiece of a microscope.
A scale is etched on to the glass disc.
This scale is typically 10 mm long and is divided into 100 sub-divisions.
The scale is visible when doing what?

Answer 6

The scale is visible when looking down the eyepiece of the microscope

Question 7

The scale on the eyepiece graticule cannot be used directly to do what?

Answer 7

The scale on the eyepiece graticule cannot be used directly to measure the size of objects under a microscope’s objective lens

Question 8

The scale on the eyepiece graticule cannot be used directly to measure the size of objects under a microscope’s objective lens, because each objective lens will do what?

Answer 8

The scale on the eyepiece graticule cannot be used directly to measure the size of objects under a microscope’s objective lens, because each objective lens will magnify to a different degree

Question 9

The scale on the eyepiece graticule cannot be used directly to measure the size of objects under a microscope’s objective lens, because each objective lens will magnify to a different degree.
The eyepiece graticule must first be what for a particular objective lens?

Answer 9

The eyepiece graticule must first be calibrated for a particular objective lens

Question 10

The scale on the eyepiece graticule cannot be used directly to measure the size of objects under a microscope’s objective lens, because each objective lens will magnify to a different degree.
The eyepiece graticule must first be calibrated for a particular objective lens.
Once calibrated in this way, the eyepiece graticule can remain how?

Answer 10

Once calibrated in this way, the eyepiece graticule can remain in position for future use

Question 11

The scale on the eyepiece graticule cannot be used directly to measure the size of objects under a microscope’s objective lens, because each objective lens will magnify to a different degree.
The eyepiece graticule must first be calibrated for a particular objective lens.
Once calibrated in this way, the eyepiece graticule can remain in position for future use, provided that what?

Answer 11

Once calibrated in this way, the eyepiece graticule can remain in position for future use, provided that the same objective lens is used

Question 12

The scale on the eyepiece graticule cannot be used directly to measure the size of objects under a microscope’s objective lens, because each objective lens will magnify to a different degree.
The eyepiece graticule must first be calibrated for a particular objective lens.
Once calibrated in this way, the eyepiece graticule can remain in position for future use, provided that the same objective lens is used.
It is therefore sensible to do what?

Answer 12

It is therefore sensible to:

1. Record the results of the calibration for a particular objective lens
2. Leave this attached to the microscope

Question 13

The scale on the eyepiece graticule cannot be used directly to measure the size of objects under a microscope’s objective lens, because each objective lens will magnify to a different degree.
The eyepiece graticule must first be calibrated for a particular objective lens.
Once calibrated in this way, the eyepiece graticule can remain in position for future use, provided that the same objective lens is used.
It is therefore sensible to record the results of the calibration for a particular objective lens and leave this attached to the microscope.
This will save you having to do what?

Answer 13

This will save you having to recalibrate each time you want to measure the size of the object being viewed under the microscope

Question 14

To calibrate an eyepiece graticule, you need to use what?

Answer 14

To calibrate an eyepiece graticule, you need to use a special microscope slide called a stage micrometer

Question 15

To calibrate an eyepiece graticule, you need to use a special microscope slide called a stage micrometer.
This special microscope slide also has what etched onto it?

Answer 15

This special microscope slide also has a scale etched onto it

Question 16

To calibrate an eyepiece graticule, you need to use a special microscope slide called a stage micrometer.
This special microscope slide also has a scale etched onto it.
Usually the scale is what?

Answer 16

Usually the scale is 2 mm long

Question 17

To calibrate an eyepiece graticule, you need to use a special microscope slide called a stage micrometer.
This special microscope slide also has a scale etched onto it.
Usually the scale is 2 mm long and its smallest sub-divisions are how long?

Answer 17

Usually the scale is 2 mm long and its smallest sub-divisions are 0.01 mm, 10 μm

Question 18

When the eyepiece graticule scale and the stage micrometer scales are lined-up, it is possible to calculate what?

Answer 18

When the eyepiece graticule scale and the stage micrometer scales are lined-up, it is possible to calculate the length of the divisions on the eyepiece graticule