Introduction to the B iology Lab

1. Introduction to theBiology Lab The Scientific Method

2. Laboratory Safety

3. Student Conduct • Do NOT smoke, eat, drink, or bring food or drinks into the laboratory room • Do NOT apply cosmetics or handle contact lenses • Wash your hands thoroughly with soap and water before leaving the laboratory room each day • Do NOT remove organisms or chemicals from the laboratory • Work carefully and methodically • COME PREPARED TO LAB FOR THAT DAY’S WORK

4. Basic Laboratory Safety • NO OPEN-TOED SHOES • Secure loose hair and clothing to avoid accidents • Place non-essential books, etc. out of the way of your experiments • Never pipette by mouth

5. Safety Equipment • Know the location of the First Aid Kit • Know the location and proper way to use the Shower • Know the location and proper way to use the Eye Wash Basin • NOTIFY YOUR INSTRUCTOR OF ANY EVENT THAT NECESSITATES THE USE OF THESE

6. Disposing of Materials • Common paper and uncontaminated towels can be placed into the normal trash • Cotton swabs, coverslips, and other used lab material MUST be placed into the red, plastic trash receptacle • Broken glassware MUST be placed in the cardboard “sharps” container for glassware

7. Care of Microscopes • Microscopes are located at each lab station • Following their use, miscroscope: • Scanning (4X) lens should be in place • Stage should be at lowest setting • Rheostat should be adjusted to its lowest setting • Cord should be wrapped carefully around the base and not “flopping” around • Ocular lenses should face back of cabinet YOUR INSTRUCTOR WILL INSPECT THEM BEFORE YOU ARE PERMITTED TO LEAVE

8. Care of the Lab • Place seats back under benches before you leave • Wipe down the sink-tops with paper towel if you are among the last students in the lab • Remove any paper towels left behind by less conscientious students THE LAB SHOULD LOOK AS NICE AFTER YOU ARE DONE AS IT DID BEFORE YOU STARTED

9. Check Your Understanding • What is the last thing you should do each day before leaving the lab? • What is the only mandatory piece of “clothing” required for you to be able to work within the lab? • Differentiate between where you should dispose of paper towels and other paper items, cotton swabs and other used lab items, and broken glassware. How should you clean up a piece of broken glassware? • Discuss the proper way your microscope should be put away after each use. • Following completion of any lab session, describe how your: • lab bench should look (including chair). • lab sink should look.

10. Scientists Make Observations and Then Form and Test Hypotheses Scientific Method

11. Scientific Inquiry • Science is a “way of knowing” • Understanding of the natural world • Inquiry is the methodical approach for deriving answers to questions posed by observations of the world around us

12. Making Observations • Recorded observations are data • Qualitative – descriptions rather than measurements • Quantitative – recorded measurements (tables/graphs) • Leads to Inductive Reasoning • Generalizations are derived from numerous specific observations • e.g. “Goldfish and roses and mushrooms are made of cells, therefore all organisms are made of cells”

13. Forming and Testing Hypotheses • Seeks to explain the cause of behind an observation • Hypotheses provide tentative answers based on available data and inductive reasoning • Deductive Reasoning is used to validate hypotheses • Uses general premises to extrapolate what the results should be if the premises are true • “if…then” logic (e.g. “if humans are organisms, then humans are made of cells”)

14. Types of Hypotheses • Null is stated as a negative • e.g. “Humans are not made of cells” • Alternative is stated as a positive • e.g. “Humans are made of cells” • The null and alternative hypotheses are mutually exclusive and both cannot be true

15. Hallmarks of a GOOD Hypothesis • It must be testable • Hypotheses must have a way of being validated • It must be falsifiable • Hypotheses can NEVER be proven true beyond a shadow of a doubt • New experimental techniques may invalidate (falsify) it

16. Experimental Controls and Repeatability • Controlled Experiments compare an experimental group with a control group • Should differ in only one factor (Independent Variable) • The control group is used to cancel out all effects that the scientists is NOT interested in examining • Observations in science are only convincing if the results are repeatable

17. Theories in Science • Scientific theories are much broader in scope than simple hypotheses • Scientific theories typically give rise to many new hypotheses that can be tested • Scientific theories are supported by a wider range of experimental evidence than single hypotheses • Theories, like hypotheses, are falsifiable given new experimental data

18. Check Your Understanding • Discuss the implication of the fact that lab work performed by scientists uses scientific inquiry. • Differentiate between quantitative and qualitative data (observations). • Differentiate between deductive and inductive reasoning. How does each contribute to our understanding of the natural world around us? • Define hypothesis. Differentiate between a null and an alternative hypothesis. What are the hallmarks of a “good” hypothesis? • Explain what a controlled experiment is. Why is important to always strive to perform a controlled experiment? Differentiate between a dependent and an independent variable. • Compare and contrast a theory and a hypothesis.