Unit C: Cycling of
Matter in Living Systems
• Aristotle is known as “The
Father of Biology.”
• He was one of the first Greek
philosophers who used the
Scientific Method of observing,
recording, reasoning, and
interpreting in attempt to
explain the world around him.
3000 years ago: Egypt &
• Glass – the material for
Early 1200s: Roger Bacon
• Described how crystal
lenses might improve
vision of the elderly
Late 1200s: Salvino degli
• Made the first pair of
• Lenses were fashioned
• A new branch of
physics, called optics,
was born to explain
the movement of light
1600s: Telescopes & Microscopes
• 1595 Hans and Zacharias Janssen (Holland) invent the
first 2-lens compound light microscope
• 1665 Robert Hooke (England) developed a 3-lens
– Hooke observed thin slices of cork and saw what he called
• 1665 Antoni van Leeuwenhoek, an expert lens crafter
was the first to reveal the microbial world
– His daughter helped him make his microscopes
– They were the first to see the movement of different types
of cells we now call protozoa, sperm, and bacteria
Microscope by Hans and Zacharias Janssen
Figure C1.3 Hooke’s Mircroscope
• As lens technology improved over the years,
the world’s knowledge of the microscopic
world increased, allowing us to solve many
Red Blood Cells Human E. Coli bacteria
• A MICROSCOPE is an instrument with a lens
or system of lenses for magnifying specimens.
• In order to use a microscope you must be
familiar with the following:
1. Microscope Structures & Functions
2. Microscope Handling Protocol
3. Calculating Magnification
4. Unit Conversion
5. Field of View
1. Eye Piece or Ocular Lens.
2. Coarse Focus Adjustment
4. Stage Clip
5. Fine Focus Adjustment
Handling A Microscope
1. Always carry the microscope in an upright
position with two hands: one on the base,
the other on the arm.
2. Use only lens paper to clean lenses.
3. Make sure the power switch is off before
you plug it in.
4. Never allow the lens to touch the slide.
5. Never attempt to repair the microscope
6. Use stage clips to hold the slide steady.
7. Always start to focus on the low-power
objective lens first.
8. Use the coarse focus first.
9. Never use the coarse focus on the high-
power objective lens.
10. When you are finished:
a) Rotate to the low-power objective lens
b) Remove the slide
c) Turn the microscope off
d) Put the dust cover on
e) Remove the power cord from the socket by the
• The MAGNIFICATION tells the reader how
much larger (or smaller) the picture is than
the real size of the item
• In order to calculate the magnification of a
system use the following formula:
Magnificat ion objective lens ocularlens
pg. 244 Calculating Magnification
What is the magnification if the following
combinations of lenses are used?
a) A 2.5X low-power objective lens and a 10X
b) A 100X high-power objective lens and a 10X
Line Master 1: Units of Measurement
Unit Equivalent Measurement
Centimetre (cm) 1/100 metre; 10–2 m
Millimetre (mm) 1/10 centimetre; 10–3 m
Micrometre—also known 1/1000 millimetre; 10–6 m
as the Micron (μm)
Nanometre (nm) 1/1000 micrometre; 10–9
Angstrom (Å) 1/10 nanometre; 10–10 m
Complete the following table.
______ cm 1.6 nm
400 A ______ mm
Field of View
• The FIELD OF VIEW is the entire area that you
see when you look through the microscope.
• Activity: Look at your partner through a paper
towel roll. Now, get your partner to walk
closer to you. Do you see more or less of your
partner? Does your partner appear larger or
smaller when he or she is closer to you? The
same idea applies to magnification:
• Magnification increase the size of what you see
BUT decreases the amount of the object in view
• Since the field of view decreases in size in direct
proportion to the increase of the magnification,
we can calculate the size of the other fields of
• For example: If the field of view is 4000μ at
40X, it will be 10 times smaller at 400X, or
400μ in size.
Calculating Field of View
Complete the following table:
Lens Field of view Field of view
Magnification (mm) (μm)
40 4 4000
100 1.6 1600
400 0.4 400