Science EquipmentScience Equipment

Aides to learning BiologyAt Post Falls High School!

Why Science is moving so fast…

• 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 MicroscopeThe 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!”

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Total magnification is the power of the ocular lens (eyepiece) times the power of the objective lens (near the OBJECT being viewed).

Here we see10 X 10 = 100 times larger than normalMaximum of our scopes is 10 X 40 = 400XMinimum 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

• 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 BalanceThe 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 Tools That Separate SubstancesSubstances

• 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

DissectionDissection• 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/StainsIndicators/Stains

• Chemical colorings that aide in the study of living things and the chemicals that compose them

Common-acid base indicatorsCommon name pH range Color change (acid to base)Methyl violet 0–2, 5–6 Yellow to blue violet to violet

Thymol blue 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

• 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/GraphsCharts/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?

• 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 ENDTHE END