Transcript The Tools of Science

Science Equipment
Aides to learning Biology
At Post Falls High School!
Why Science is moving so fast…
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Our senses are weak and limited
New tools have been invented
Old tools have been improved
Technology has been introduced into
all facets of study
• The computer is faster than us
• Memory chips are more efficient than
our brains
The Microscope
Lenses magnify
image of object
placed on stage and
held in place by clips.
Lamp below stage
illuminates the
specimen. Focus
knobs make image
clear for study. Arm
and base are for
supporting and
transporting the
microscope safely.
“Two hands for
beginners!”
Click here for more
Total magnification is
the power of the
ocular lens (eyepiece)
times the power of
the objective lens
(near the OBJECT
being viewed).
Here we see
10 X 10 = 100 times
larger than normal
Maximum of our
scopes is
10 X 40 = 400X
Minimum is
10 X 4 = 40X
Specimen on stage
secured by clips.
Use low power first.
Rack down looking
from the side.
Slowly rack up using
coarse focus until
image comes into
view. Focus with fine
focus. Change to
medium power lens.
Repeat steps until
you have image to
study under high
power. Always
sketch and describe
what you see.
Compound Light Microscope
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View objects too small for naked eye
View living objects in action
Lenses bend light rays to magnify
Viewed directly with eye which can
perceive visible light spectrum
• Range from 100X to 2000X
Electron Microscope
• View objects to small for the
resolving power of light microscope
• Cannot view living things in action
since they must be viewed in a vacuum
• Uses electron beams instead of light
• Can be viewed only on monitor
• Range to 500,000X, then enhanced by
computer imaging to almost
1,000,000X
The Balance
Triple Beam Balance
• Place the item on
the pan
• Move the riders to
the right, largest
first, until pointer
lines up with the
zero mark
• Read and add
values for full mass
Electronic/Digital Balance
• Set to “on” and
place object on pan
• Can figure tare
weights (contents
without container)
• Very accurate –
eliminates a lot of
human error
Tools That Separate Substances
• Centrifuge
• Gel Electrophoresis
• Chromatography
Centrifuge
• Separate
substances in a
solution by density
• Spinning action
separates the
densest to the end
of the tube, with
the least dense
near the mouth
Gel Electrophoresis
• Substance tested is
negatively charged
• Current through the
gel moves + to – and
vice-versa
• Smallest moved
fastest (farthest)
• Separation by charge
and size
• Leaves comparable
patterns (DNA, e.g.)
Chromatography
• Test chemical placed
as a dot on the paper
• Solvent added above
and runs down
carrying components
• Components carried
and deposited at
different rates
leaving separate
streak patterns
Dissection
• Biology sometimes
involves dissection to
better understand
the appearance and
function of
structures and how
they compare to
those in other
organisms. This
requires special tools.
• Scalpel for cutting large
structures (A)
• Scissors for more delicate
cutting without damaging
below (B, C)
• Forceps for grasping small
parts and holding while
cutting (D, E, F)
• Dissecting needles for
probing, lifting, holding, etc.
(G, H)
• Pins for securing specimen
in wax-bottomed pan
• Eyedropper for moistening
Plant Press
• To flatten and dry
botanical specimens
• Light, portable,
easy to make/use
• Makes plant
collections much
easier
Indicators/Stains
• Chemical colorings
that aide in the
study of living
things and the
chemicals that
compose them
Common-acid base indicators
Common name
Methyl violet
Thymol blue
pH range
0–2, 5–6
Color change (acid to base)
Yellow to blue violet to violet
1.2–2.8, 8.0–9.6
Red to yellow to blue
Bromphenol blue
3.0–4.6
Yellow to blue
Methyl orange
2.8–4.0
Orange to yellow
Bromcresol green
3.8–5.4
Yellow to blue
Methyl red
4.2–6.3
Red to yellow
Bromthymol blue
6.0–7.6
Yellow to blue
Phenol red
6.8–8.4
Yellow to red
Phenolphthalein
8.4–10.0
Colorless to pink
Thymolphthalein
10.0–11.0
Colorless to red
Malachite green
11.4–13.0
Green to colorless
Common Stains
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Lugol’s iodine tests for starch
Benedict’s solution tests for simple sugar
Ninhydrin tests for proteins
Sudan III tests for lipids
Methylene blue stains cell parts for
viewing under the microscope
Charts/Graphs
Collecting/Analyzing Data
• Write down quantitative data
• Organize, analyze, express data in
charts/graphs; location of certain
data easier; patterns identifiable
• Important support for hypothesis
being tested
• Makes reports and papers easier to
understand
Computers
How Do They Help?
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Enhances existing equipment
Designs experiments; runs simulations
Runs tests
Formats and records data
Processes reports, including graphics
Allows quick, massive research
Speeds up all scientific work, as well
as training
How Do They Help?
• Often, data collected is enormous.
Sorting, analyzing, and collecting data
is made quicker, more efficient, and
more accurate by computer use. The
Human Genome Project was made
possible by use of supercomputers
that were able to deal with the
gigantic amounts of data involved with
cataloging info about our genes.
What you should be familiar
with for working in the lab….
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THE END