1. Scientific Method, Microscopes, and the Metric System

2. Science as a Process Steps of the Scientific Method
Involves making observations, asking questions, forming hypotheses, making predictions, designing experiments, analyzing data, and drawing conclusions

3. Scientific Method Steps
Step 1: State Problem or Question
Observation – using all senses to gather information
Inference – assumption based on observation

4. Scientific Method Steps
Step 2: Gather information
Accuracy (correct ) vs. Precision (closeness of measurements together)
Quantitative (1 cm, 45 kg, etc.) vs. Qualitative (cloudy, fuzzy, blue, etc.)
Step 3: Form Hypothesis
Hypothesis - proposed explanation for the way a particular aspect of the natural world functions.
If … Then Statement
If he studies his biology notes every night, then he will pass the biology Keystone exam.

5. Scientific Method Steps
Step 4: Test Hypothesis
Performing the Experiment
A controlled experiment compares an experimental group and a control group and only has one variable.
1. Control group - provides a normal standard against which the biologist can compare results of the experimental group.
2. Experimental group is identical to the control group except for one factor.
Independent variable – intentionally changed
Dependent variable - affected by the independent variable
Experiment should be repeated and completed without bias

6. Scientific Method Steps
Step 5: State Conclusion
Hypothesis must be accepted or rejected through data from experiment
When writing conclusion:
Hypothesis must be stated
Include data that accepts/rejects hypothesis
Step 6: Share Results
Publish results in scientific journal to share with community

7. Quick Review
List the steps of the scientific method in the correct order.
1. _____________________________________________________
2. _____________________________________________________
3. _____________________________________________________
4. _____________________________________________________
5. _____________________________________________________
6. _____________________________________________________

8. Theory vs. Law
Theory - set of related hypotheses confirmed to be true many times, and it can explain a great amount of data
Law – general statement that describes a wide variety of phenomena under specific set conditions

9. Microscopes as Tools Light Microscopes
A compound light microscope is a microscope that shines light through a specimen and has two lenses to magnify an image.
Four major parts of a compound light microscope are the ocular lens, objective lens, stage, and light source.

10. Microscopes as Tools Light Microscopes Eyepiece magnifies the image.
Objective lens enlarges the specimen.
Stage is a platform that supports slides with specimens.
Light source is a light bulb that provides light for viewing images.

11. Microscopes as Tools, continued
Magnification and Resolution
Magnification is the increase of an object’s apparent size.
Resolution is the power to show details clearly in an image.

12. Object Size and Magnifying Power of Microscopes

13. Microscopes as Tools, continued
Electron Microscopes
In an electron microscope, a beam of electrons produces an enlarged image of the specimen.
Provide greater magnification and resolution than light microscopes

14. Microscopes as Tools, continued
Electron Microscopes
Scanning electron microscopes pass a beam of electrons over the specimen’s surface for better viewing the external surface of a specimen.
Transmission electron microscopes transmit a beam of electrons through a thinly sliced specimen for better viewing the internal structures of a specimen.

15. Quick Review
Why are microscope an important tool for the scientific community?

16. Units of Measurement Base and Other Units
Scientists use a single, standard system of measurement, called the metric system
King Henry (KHDSDCM) – use for conversions
Kilo (k)
Hecto (h)
Deca (da)
Standard (m,l,g)
Deci (d)
Centi (c)
Milli (m)
Ex. 18m = 1800cm
Ex. 2.4dag = 0.024kg

17. Quick Review Using King Henry complete the following conversions:
12 g = ______________ cg
.75 dL = ____________ daL
1346 hm = ____________ m

18. Units of Measurement Base and Other Units
Metric system has seven base units
Commonly used ones for this course:
Meter (m) – distance
Liter (L) – liquid measurement
Gram (g) - weight