2. The Scientific Method The scientific method is an organized way to solve a problem

3. Steps of the Scientific Method 1.State the problem Formulate a question that needs to be answered 2. Propose a hypothesis A hypothesis is an educated guess about what the solution to the problem is. 3. Test the hypothesis. Testing is done through experimentation. All experiments should contain a variable or a condition which can be changed. Experiments also include a control in which no change is made. The control serves as the reference. B2

4. Steps of the Scientific Method 4. Observations and data. The results of the experiment are recorded as data. Observations are made with our sense and instruments 5. Analysis & Conclusions The data from the experiment needs to be looked at and analyzed. After this is done, a conclusion or answer to the problem 6. Report & Repeat Conclusions must be reported so that other scientists can repeat the experiments B3

5. Laws & Theories When a hypothesis has been put through the steps over and over again, it may become scientific theory (ex. Theory of Evolution, Theory of Relativity) A scientific law is a theory that has been proved so thoroughly over a long period of time that it is considered a fact or truth (ex. Law of Gravity) B4

6. Example of the Scientific Method Example of the Scientific Method: –Problem: Does the green plant need sunlight to survive? –Hypothesis: A green plant will wilt and die if kept in the dark. –Test of hypothesis (experiment): Take two plants of the same type, size and in the same soil. place one in sunlight (the control) place the other in complete darkness (variable) water each plant at the same time every day with the same water –Make Observations: Record in writing the differences you observe between the two plants. –Conclusion: Analyze the observations and draw your conclusions. –Repeat the Experiment: Do another experiment to assure the same results. B5

7. Independent & Dependent Variables Independent Variable: A variable that is controlled by the experimenter; the ONLY one over which YOU have direct control. Dependent Variable: The thing that you measure in the experiment (Ex. Height of plant) Conventionally the independent variable is plotted on the horizontal axis (also known as the x-axis) and the dependent variable on the vertical axis (or the y-axis) B6

8. Independent & Dependent Variables

10. a.Eyepiece b.Coarse Adjustment c.Fine Adjustment d.Objectives (LP, HP) e.Arm f.Stage g.Light source h.Base i.Diaphragm

11. a.Magnifies image (10X) b.Used for rough focus (use with low power) c.Used for fine adjustments (use with high power) d.Enlarges image (scanning 4x, low power 10x, high power 40x) e.Used for carrying microscope f.Platform for holding the slide g.Can be a mirror or light bulb h.Used for carrying the microscope i.Adjusts the amount of light

12. 10x x 4x = 40x magnification magnification total of eyepiece lens of obj. lens magnification The specimen being viewed is magnified 40 times. The greater the total magnification, the smaller the field of view (FOV) or area that you see. The lower the total magnification, the larger the field of view (FOV).

13. Calculate the total magnification: Eyepiece Lens Objective Lens Total Magnification a. 10x4x 40x b. 10x10x 100x c. 10x40x 400x

14. Question 2: With which combination of lenses would you be able to see the largest area of a specimen? Eyepiece & scanning(4x) (largest FOV) or eye & low power ( 10x) if scanning is not there The smallest area? Eyepiece 10x & High power 40x (smallest FOV) Question 3: Which set of lenses would you use to locate a specimen on a slide? Eye & 4x(scanning) or 10x (low power) Which set would you use to examine the details of a specimen? Eyepiece & 40x (high power)

15. FIELD OF VIEW -How much can you see? In High Power we see 25% of the low power FOV (low power 100 x is 25% of high power 400x) We see less of the specimen but we see more details of the specimen under high power LOW POWER

16. 1. After switching from high power to low power the area of the field of view will appear a. larger and brighter b. Smaller and brighter c. larger and darker d. smaller and darker 2. What should a student adjust if the field of view seems too dark? ________________________________ 3. Is the field of vision smaller or larger under low power? ______________________________________

17. 4. To locate and observe a specimen under a slide, a student should begin by using what objective and what adjustment knob? 5. What adjustment knob should you use if you are using high power? 6. Why should a specimen be centered in the middle of the field of view when focusing under low power?

18. The limit of resolution restricts the usefulness of light microscopes for studying VERY small specimens such as viruses. Electron microscopes use a stream of electrons to view these specimens. Electron microscopes have a limit of resolution more than 1000 times finer than light microscopes.

20. How do we find the FOV of a microscope? Low Power (100x) 1.Find the diameter of the LP FOV 2.Use the clear metric ruler (mm side) 3.Be sure to line up the first mm mark with the left side of the field. LP FOV = 1.5 mm

21. 1 mm = 1,000 µm 1 µm = 1/1000 mm or 0.001mm LP FOV = 1500µm

22. Let’s see how it works: Use the following formula: FOV # of cells (that can fit across diameter) FOV = 2mm =.5mm # of 4 cells OR.5mm x 1000 =500 microns

24. 1. metric ruler- measures length 2. Graduated cylinder-measures Volume To read the volume, you must look at the bottom of the _____________ which is a curve surface.

25. 3. Triple beam balance and electronic balance measure mass in grams. 4. Probe and scapel are used for dissection

26. 5.Centrifuge is a tool used for separating substances of different densities. Parts of a cell and blood are separated this way.

27. 6. Chromotography- technique used to separate substances based on their chemical make up ( the different colors of leaves are separated this way)

28. 7. Gel electrophoresis -technique used to separate substances based on their electrical charge. (DNA is separated this way)

29. 8. Microscope- a tool used to magnify objects. a. compound microscope uses 2 lenses. b. stereoscope also called a dissection microscope. This has 2 oculars (eye pieces) is used to observe external parts of a specimen.

31. All made of the same collection of chemicals, but we are organized as… –molecules proteins, fats, carbohydrates, nucleic acids carbohydrates DNA proteins A2

32. Living creatures are ORGANIZED All made of the same collection of chemicals, but we are organized as… –organelles & cells plant cells & animal cells animal cell plant cell A3

33. All made of the same collection of chemicals, but we are organized as… –organs & organ systems respiratory, circulatory, digestive, etc. A4

34. An organism is said to be alive as long as the cells perform these __8__ life processes. 1. Nutrition- Taking in food and processing the materials needed for life There are 2 types: Autotrophic- Plants- Make own food Heterotrophic- Animals- Need to go out and get food A5

35. Release of energy from the food and oxygen we take in. Mitochondria is the organelle that performs respiration. There are two types: –Aerobic- uses oxygen to make energy –Anaerobic- does not use oxygen to make energy A6

36. Removal of liquid wastes. Egestion-is the removal of solid wastes. A7

37. Control of all activities in an organism. This helps maintain balance (Homeostasis). 2 body systems work to maintain this-Nervous and Endocrine(hormones) A8

38. To increase in size A9

39. Making simple substances more complex. Example Photosynthesis- plants use Co2 and H2o along with sunlight to make Glucose (sugar) A10

40. Distributing materials throughout the organism. Examples: Cytoplasm – liquid within the cell Circulatory system- blood carries materials needed for body ( oxygen, nutrients, hormones) A11

41. Production of a new individual. Not needed for individual to survive.Must have for the species to survive. Two Types: Sexual- 2 Parents Asexual- 1 Parent A12

42. A Virus is an exception. It cannot carry out all the life processes. To stay alive a virus must invade the cell of a living organism. It needs a Host cell to stay alive. A13

43. Is the total of all the life processes. When a person states he has high or low metabolism this is what they are talking about. It is the combination of all the life functions working together. A14

44. Is the body maintaining internal balance (a steady state). When all the life processes are occurring normally, it is maintaining homeostasis. A15

45. If a body is not in homeostasis then FEEDBACK MECHANINSMS kick in Examples : Body Temperature- Sweating –cools body Shivering- heats the body Sugar Levels- –Pancreas produces hormone called Insulin- maintains glucose (sugar) levels A16

46. A17