2. Behaviour and Expectations
Line up in a single line outside the classroom quietly before the second bell
No eating or drinking in the lab
(this includes brain food)
Bring required things to class
Put rubbish in the bin
Follow laboratory safety rules during practicals
At the end of the lesson, stand in silence
until you are dismissed
Complete all set homework – this will be checked!

3. What to bring to Science
Blue/Black/Red Pens
Highlighters
Glue Stick and Scissors
Ruler
Rubber
Sharpener
Grey lead pencil
Charged Laptop:
Pearson e-book
IntoScience
Science exercise book
Practical book
Planner/Student Diary

4. Making things bigger
Module 2.1 (page 46)

5. Microscopes All living things are made up of cells
Cells are microscopic, can’t be seen with the naked eye.
Small things need to be magnified or made bigger so that they become visible to us.
Scientists use microscopes to do this.
Objects that can only be seen using a microscope are called microscopic.
Microscopes

6. Two types of microscope
Light microscope:
compound (magnify thing about 1000 times)
dissecting (magnify things about 100 times)
2. Electron microscope:
magnify things about 1,000,000 times
Two types of microscope

8. Monocular
Binocular
Stereo or
Dissecting

9. Light Microscopes These are used in schools.
Light from a mirror or a lamp passes through the specimen or object.
The specimen must be thin so that the light can pass through it.
The light then passes through the lenses that make the specimen look larger.
Light Microscopes

11. Electron microscopes
Electron microscopes are more powerful than light microscopes
Allows specimens to be magnified up to a million times
Beams of tiny particles called electrons are used rather than light
Images are shown in black & white
Two types of electron microscope  TEM & SEM

13. Comparison Light Microscope Electron Microscope Advantages
Disadvantages
Cell can be alive
Not high magnification
Easy to prepare
Light must be able to pass through – very thin specimen
Sometimes need to be stained
Comparison
Electron Microscope
Advantages
Disadvantages
High Magnification
Cell needs to be prepared
Can see structures & organelles
Images are black and white

14. Complete the Using a Microscope Worksheet
Use the interactives on the class website,
to complete the microscope worksheet
Complete the Using a Microscope Worksheet

15. Label the following parts of the microscope with their correct name
Ocular lens
Label the following parts of the microscope with their correct name
Course Focus
Fine Focus
Objective lens
Arm
Stage
Mirror/Lamp

16. Match the part of the microscope with its description
Part of the microscope on which the specimen is placed
Sharpens the focus on high magnification
The lens of the microscope closest to the specimen
The part of the microscope you look through
Used to reflect light through the specimen
Used to focus the microscope on low power
Used to carry the microscope
Stage
Match the part of the microscope with its description
Fine focus
Objective lens
Ocular lens
Mirror
Coarse focus
Arm

18. Viewing a slide under a microscope
Place on low power (what is the magnification)
Look through the eyepiece and turn on the light and see as a circle of light
Place the object/slide on the stage under the clips.
Look at the microscope side-on and use the coarse focus knob to wind the body tube to its lowest point just above the slide.
Look through the eyepiece and, with the fine focus knob, wind the body tube upwards away from the slide until the slide is in focus. Never move the objective lens down when looking down the microscope
Draw what you see under low power
Once in focus, turn it to a higher power (magnification) and bring the object into focus using the fine focus knob. What is the new magnification of the slide now? Record this in your results section.

19. Very small measurements
Objects viewed under the microscope are smaller than 1mm. The unit of measurement used to measure microscopic objects is the micrometre (µm)
There are 1,000 micrometres in 1 mm.
If a cell is 50 micrometres across, how many would you observe if your field of view was 2 mm?
Very small measurements
1mm: (50 x 1000) = cells
2mm: ( x2) = cells

20. A blow fly: actual size - no magnification
Magnification refers to how much larger a sample appears to be compared to its actual size.
As magnification level increases, the amount of specimen you see gets smaller because you are zooming in
A blow fly: actual size - no magnification
x5 magnification
Magnification
x20 magnification
x50 magnification

21. Calculating magnification
You view the specimen through two lenses: the ocular lens (eyepiece lens) and one of the objective lenses.
The total magnification can be calculated by multiplying the magnification of the eyepiece lens with the magnification of the objective lens.
Total Magnification =
Ocular lens x Objective lens
Calculating magnification

22. Calculating magnification

23. Calculating magnification
Ocular lens
Objective lens
Total mag
x 10 x4 A?
x 2 x5 B? C?
x 20
100 D?
800
x10 E? 80 40
Calculating magnification 10 x5
x40 x8

24. Making a wet mount slide
Preparing a Wet Mount
Place the specimen in the center of a clean, grease-free microscope slide.
Cover the specimen with a drop of water or other suitable mountant such as glycerol.
Hold a coverslip at an angle so that its bottom edge is in contact with the drop on the slide.
Use a mounted needle to support the coverslip and lower it gently over the specimen. This avoids including air in the mount.
Making a wet mount slide
Mounted needle
Specimen
Coverslip
Mounting fluid
Glass microscope slide

25. Rules for drawing microscope diagrams
Label your diagram or specimen (heading)
Record the magnification.
Draw what you see with one eye still viewing the specimen down the microscope
Draw only a few cells
Draw large diagrams (1/3 of a page)
Use a grey lead (never colour) or pen
Use solid lines (no shading)
All labels on the same side (if you can), use a ruler, labels to the right.

26. Example

27. drawing microscope diagrams
CORRECT
INCORRECT

28. Review Questions (page 52)