microscopy

Question 1

what is a hand lens?

Answer 1

used to magnify objects that are visible to the naked eye

Question 2

what can you see with a hand lens?

Answer 2

• colour
• texture
• shape
• size

Question 3

what hand lens be used for?

Answer 3

• finger print matching

- seed/insect identification

Question 4

pros and cons of a hand lens?

Answer 4

\+ easy to use
\+ good for small objects
\+ portable and cheap
- not practical and have to maintain the distance
- field of vision is limited

Question 5

what is magnification?

Answer 5

is how much bigger the image you see is than the actual specimen itself

Question 6

what is resolution?

Answer 6

is how detailed an image is

- how well a microscope distinguished between two points that are close together

Question 7

what is a light microscope?

Answer 7

is a tool that uses visible light to detect and magnify very small objects and enlarging them

Question 8

pros and cons of light microscopes?

Answer 8

\+ greater resolution than hand lens
\+ easy to use
\+ small and portable
\+ can observe living organisms
- doesnt show any living internal structure
- cannot show 3d images

Question 9

what is the difference between magnification and resolution?

Answer 9

magnification is the ability to make small objects seem larger whereas resolution is the ability to distinguish two objects from each other

Question 10

hazards of light microscopes?

Answer 10

• allow to cool before transporting/transmitting

- hold by the arm and under the base

Question 11

what is the practical with the onoin?

Answer 11

1. add a drop of water to the slide
2. add a single layer of onion tissue to the slide
3. add a drop of iodine to stain the cell components
4. lower the cover slip at an angle, to avoid air bubbles
5. draw an accurate observation and label key features

Question 12

how do you draw observations?

Answer 12

• draw what you see under the microscope using a sharp pencil
• it is drawn clearly with unbroken lines
• no title, write magnification it was observed under

Question 13

what is the formula for magnification?

Answer 13

magnification = image size/real size

Question 14

what is scale bar length?

Answer 14

drawn length (um) x 500/ actual length (um)

Question 15

what is an electron microscope?

Answer 15

uses a beam of electrons to magnify an objects image contain a vacuum as air particles would interfere with the beam

Question 16

pros and cons of electron microscopes?

Answer 16

\+ higher range of magnification
\+ higher resolution
\+ clearer image
- cannot work on live specimens
- expensive and not portable
- must have training to use
- must have the right temp, pressure and humidity in the room

Question 17

what are two types of electron microscopes?

Answer 17

transmission electron microscope (TEM)

scanning electron microscope (SEM)

Question 18

what is TEM?

Answer 18

uses a beam of electrons which have a much shorter than light. TEM’s can magnify up to 500,00 times

Question 19

pros and cons of TEM?

Answer 19

+ very high resolution
+ can see internal structures
- only used on thin specimens
- electrons transmitted through the specimen

Question 20

what is SEM?

Answer 20

scans electrons over the surface of the specimen, so you can get a 3D image

Question 21

pros and cons of SEM?

Answer 21

\+ can be used on thick specimens
\+ can see images in 3d
- lower resolution images
- electrons bounced off the specimen
- lower resolving power then TEM

Question 22

what is the relationship between the field of view and magnification?

Answer 22

the higher the power of magnification, the smaller the field of view