Field and lab investigations

• Science is a process

• We begin with a question, and seek an answer by investigating the natural world

• We use a variety of methods to investigate– Conduct experiments– Work of other scientists

• We use tools (lab equipment) to help us find the answers we seek

• Never eat or drink in the lab.• Remain alert at all times.• Keep your area free of clutter.• Follow both written and verbal directions.• Unauthorized experiments can be

dangerous.• Report any accident, incident, or hazard to

me immediately, even if you think it’s “no big deal.”

• Students may not work alone.• Remain at your workstation.

The world needs more

Lerts!

• Always wear goggles and other safety items.

• If you get any chemical in your eyes, immediately flush your eyes (including under your eyelids) with water at the eyewash station for at least 15 minutes. Notify your teacher.

• Secure all loose items.• Hair should be pulled back.• Contacts are not allowed. • Know where to find the safety equipment

Blood and Body Fluids Safety

• Wear gloves when someone is bleeding or vomiting

• Clean everything touched by blood or vomit with a disinfectant

• Remove your latex gloves by pulling them off inside out

• All materials used to clean up blood or other possible infectious materials should be disposed of in the proper biohazardous waste bag

• Standard Biohazardous waste bags are red with the biohazardous waste symbol on them. If one is not available, use a regular plastic garbage bag and attach biohazardous waste sticker to the bag

• Wash your hands thoroughly with a disinfectant when you are finished

• Never pipette by mouth.• Throw away broken or chipped glassware• Hot glass looks like cool glass.• Hot glass does not go in water.• Point test tubes away from people when heating them.• Always pour acid into water.• Touch electrical devices only with dry hands.• Smell a chemical by waving your hand over it and

letting the smell drift to your nose.• Don’t pour chemicals down the sink.• Never return unused chemicals to the original container.

Safety Warning Symbols

Cool!Oops, I was supposed

to read the lab directions first!!!!

Caustic or corrosive- Will corrode or eat away metal, skin, or other substances. Volatile- Evaporates quickly, may form dangerous vapors.Flammable (may ignite)- will catch on fire or explode easily. Ventilation- removing contaminated air and brining in fresh air.

Safety Terms:

FlammabilityFlammabilityHazardHazard

StabilityStabilityHazardHazard

HealthHealthHazardHazard

SpecialSpecialInformationInformation

Risk Level0 Minimal1 Slight2 Moderate3 Severe4 Extreme

All chemicals must be labeled, and the label must include the NFPA hazard diamond

How dangerous is this one?

4

20

W

Extremely flammableModerately unstableNot a health riskKeep away from water

•Extinguishers must be located and marked so they are easily seen in a laboratory•The extinguisher must be inspected annually and be tagged with the inspection history

Triple Beam Balance

• To measure the mass of substances or objects accurately

• Mass is the amount of matter in an object.

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Graduated cylinder

• To measure volume of liquids accurately to within about 1%.

• They are for general purpose use, but not for quantitative analysis. If greater accuracy is needed, use a pipette or volumetric flask.

• The guard is to protect it from breaking if it tips over

The Meniscus—reading volume correctly

• When water is placed in a glass or plastic container the surface takes on a curved shape.

• This curve is known as a meniscus. Volumetric glassware is calibrated so that reading the bottom of the meniscus viewed at eye level gives accurate results.

• Viewing the meniscus at any other angle will give inaccurate results.

SI Ruler(“Metric” is slang.)

• To measure the lengths of solid objects accurately

SI thermometer

• To measure temperature accurately • Metric units are degrees Celsius, oC

Magnifying glass (hand lens)

• To make objects appear larger than they are

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Bunsen burner

• To heat substances (with a flame)

Hot plate• To heat substances using electricity, not a flame

• This is usually safer when heating chemicals

Ring stand with clamp and ring

• To hold containers away from a heat source during an experiment

Safety goggles

• To protect eyes against burns, cuts, or flying objects

Microscope

• To view specimens that are too small to see with the naked eye

Compound microscope

Eyepiece

Body tube

Revolving nosepiece

Low power objective

High power objective

Mirror (or light source)

Coarse adjustment(focus)

Fine adjustment(focus)

Arm

Stage Clip

Stage

Diaphragm (controls amount of light)

Base

Microscope Slide• To hold a specimen (sample) for viewing

through a microscope

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http://www.cat.cc.md.us/courses/bio141/labmanua/intro/stageslide.html

Cover slip

• To cover a specimen (or sample) on a slide

http://www.scitoys.com/scitoys/scitoys/thermo/liquid_metal/liquid_metal.html

Medicine dropper(Eyedropper)

• To drop small amount of liquids

Forceps• To pick up small items that you should not

touch

http://www.dryeye.org/products.htm

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Petri dish

• To grow bacteria and other tiny living things

Test tube

• To hold liquids and chemicals during experiments (investigations)

Test tube rack

• To hold test tubes during an investigation. (After cleaning, test tubes can be placed upside down to dry.)

Test tube clamp

• To hold test tubes over heat or away from your body

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Erlenmeyer flask• Used for mixing,

transporting, and reacting, but not for accurate measurements.

• The volumes stamped on the sides are approximate.

Florence flask• Used for mixing, transporting, and

reacting, but not for accurate measurements.

• The volumes stamped on the sides are approximate.

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Beaker

• Used for mixing, transporting, and reacting, but not for accurate measurements.

• The volumes stamped on the sides are approximate

Tongs

• To pick up large objects that you should not touch (e.g., hot containers, flasks of acids, etc.)

Funnel

To pour liquids or powders from one container to another without spilling anything

Stirring rod

To mix chemicals and hot liquids together by stirring

Accurate measurement

When measuring distance on the TAKS •You will have a ruler on the side of your formula sheet. •USE IT if you are asked to measure distance on a map or a length.

Measure the length of a tile.

Measure the width of your folder.

29 mL

What is the volume of liquid in this graduated cylinder?

When taking the mass of solids

•Use a mass boat or paper.

•Subtract out the mass of the container or paper to zero the balance.

•Clean up spills so they don’t corrode the balance.

Scientific Method

Observations Hypothesis Experiments

Theory

ObservationsRepeated successful

experimentsLaw

Cycle repeated until the hypothesis fits all observed experimental facts

Results may require adjusting hypothesis

Explains results

Describes natural phenomena

Reading Graphs and Making Calculations •Scientists must analyze graphs to understand an experiment’s result. •The Independent Variable on a graph is on the X-axis. •The Dependent variable is on the Y-axis.

Pie Graphs

• Pie graphs are used to show how a whole is broken up into its parts.

• Note that parts should add up to 100% when values are given

Bar Graphs

• Bar graphs are used to compare measurements taken from a number of objects or categories.

• They demonstrate trends in data

Line Graphs

• Most graphs show the relationship between two variables.

• The lines are usually drawn either straight or curved.

• These "smoothed" lines do not have to touch all the data points, but they should at least get close to most of them. They are called best-fit lines

Pictographs use symbols to represent numbers.

Always check keys and legends to accurately read units and labels on graphs.

Pictographs

Nutrition Labels• A U.S. government agency defines what

information must appear on a food label.• The meaning of terms such as “low fat” are

strictly defined for use on labels– If a label claims that the product is unsweetened

or that there is no sugar added, it means no common table sugar (sucrose) has been added.

– It does NOT mean there are no other sugars present

• Info is based on a single serving– Careful, single servings are sometimes chosen

so that the numbers “look good” at a glance check this when comparing two labels

– For example, an individual bag of chips may have three servings, rather than one

•You may be asked to calculate a % from a label. •To find a %, divide the # of items you have by the total #, then multiply by 100.

Analyzing Product Ads (consumer info)

• Every day, companies try to sell you their products. • Television commercials and newspaper and magazine

ads tell you why certain products are best. • You must use your critical-thinking and problem-

solving skills to decide for yourself if the ads are correct.– Remember—their motive is $$$ so they may

“shade” the truth to convince you; you have to outsmart them!

Feel Better Fast with Vitaplex!--Really?

• The word “scientific” is to make you believe this is factual• It’s true that your body needs protein to survive and that your body

converts protein into amino acids• It is NOT true that excess protein will not be converted into fat• Vitamins are essential to good health, but they do not provide

energy• Excess vitamins are excreted or stored in the fat (too much stored in

fat can make you ill)• So, will Vitaplex give you energy and make you feel better?