Chapter 1 The Study of Life

Transcription

1 Chapter 1 The Study of Life

2 Chapter 1 Vocabulary Accuracy (XXXiii) Precision (XXXiii) Biology (4) Science (11) Theory (11) Metric system (14) SI (14) Technology (glossary) Observation Inference Scientific method Hypothesis Serendipity Experiment Control group Independent variable Dependent variable Constant Data Safety symbol

3 Section 3 Methods of Science Standards: 1.1, 1.2, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 Objectives: Describe the difference between an observation and an inference. Differentiate among control, independent variable, and dependent variable. Identify the steps to the scientific method.

4 What is Biology? Science body of knowledge based on the study of nature. Process of inquiry that searches for relationships that explain & predict nature. Biology study of life

5 What do Biologists do? 1. Study diversity of life 2. Research diseases 3. Develop technologies Technology (applied science) application of scientific knowledge to solve human needs 4. Improve agriculture 5. Preserve environment

6 Scientific Method Scientific Method a series of problem-solving procedures that scientists use to learn about events that occur in nature.

7 Scientific Method

8 Step 1: Problem Observation process of noticing using your senses Observations Questions Purpose Inference assumption based on prior experience

9 Step 2: Research Research information related to the investigation. Research should be Reliable, Relevant, Recent Science journals wiki.answers.com wikipedia.com

10 Step 3: Hypothesis Hypothesis possible explanation of an observation that can be tested. Not a guess, but reasonable explanation based on research! Predicts relationship between independent and dependent variable. cause-effect relationship

11 Step 4: Experiment Experiment tests hypothesis under controlled conditions. One variable tested at a time Must be repeatable When are experiments supportable?

12 Step 4: Experiment Independent Variable - you manipulate (control) and change cause Dependent Variable - changes due to the independent variable (think results) effect changing the independent variable causes change in the dependent variable

13 Dependent (y-axis) Step 4: Experiment D R Y M I X Independent (x-axis)

14 Step 4: Experiment Control Group group used for comparison. Receives NO experimental treatment. Constant factor that remains fixed STAYS CONSTANT

15 Practice: Identifying Variables Impact-sensing patches tucked behind the ears of 16 University of Virginia football players counted the head knocks that happened during four types of athletic events. Independent Variable? Dependent Variable? Constants?

16 Practice: Identifying Variables Raising the average temperature of the Earth s atmosphere will cause the polar ice caps to reduce in size. Independent Variable? Dependent Variable?

17 Practice: Identifying Variables If the sugar concentration increases then the candy bar will taste sweeter. Independent Variable? Dependent Variable?

18 In a controlled experiment, the variable that is changed to test the hypothesis is called the A.Controlled variable B.Responding variable C.Dependent variable D.Independent variable

19 Sarah designed an experiment to find out which mouthwash was most effective against bacteria. She cut out 4 different circles from a paper towel and soaked each circle in a different mouthwash. She put the circles in a Petri dish covered with bacteria (commonly found in the mouth) for 24 hours. The picture shows the results of this test. What should Sarah do to improve her experiment? A. Use the same size paper circles for all mouthwashes. B. Use the same type of mouthwash on each paper circle. C. Use different kinds of bacteria D. Use a smaller Petri dish.

20 What happens to the dependent variable in a controlled experiment? A.It changes as the independent variable changes. B.It changes as the responding variable changes. C.It does not change. D.It is supported or disproved.

21 A student wants to conduct an experiment to find out how pulse rate changes as the length of time spent exercising increases. The dependent variable will be. A.breathing rate B.pulse rate C.time spent exercising D.the kind of exercise

22 A student is planning an experiment to find out how the height from which he drops a ball affects how high the ball bounces. The dependent variable is the. A.diameter of the ball B.force acting on the ball C.height that the ball bounces D.height from which the ball is dropped STOP Day 2

23 A student hypothesized that the amount of sunlight a sunflower plant receives determines the number of sunflower seeds the plant produces. In her experiment, the number of seeds produced is the. A.dependent variable B.independent variable C.controlled variable D.manipulated variable

24 In a controlled experiment, the independent variable is. A.the results of the experiment B.the variable that stays the same C.changed to test the hypothesis D.always time

25 In an experiment studying how increasing amounts of acid rain affect life in pond water, which of the following would be the dependent variable? A.organisms in rainwater B.acid rain and non-acid rain C.a mixture of pond water and acid D.number of organisms in pond water

26 An experiment for a new asthma medication was set up into two groups. Group one was given the new drug for asthma, while group 2 was given a sugar pill. The sugar pill serves as a. A.Control B.Dependent Variable C.Experimental Variable D.Constant

27 The measurable factor in an experiment is known as the: A.Control B.Independent Variable C.Constant D.Dependent Variable

28 A student sets up an experiment to see if fertilizer affects the growth of seeds. He sets up 10 total pots. 5 pots will receive a small amount of fertilizer and placed in the sun. The other 5 pots will not receive fertilizer and placed in the shade. All 10 pots will receive the same amount of water, the same number of seeds, and the same type of seeds. He measures the growth every 2 days for two months. What is wrong with his experiment? A.More than one variable is being tested. B.The student should have a larger number of pots. C.There is no way of measuring the outcome. D.There is no control set-up.

29 A student has a wagon of a certain mass. He plans to investigate how the acceleration of the wagon changes as the force he exerts on it increases. In his investigation, the independent variable is A.The acceleration of the wagon B.The force acting on the wagon C.The mass of the wagon D.The mass of the student.

30 A scientist plants two rows of corn for experimentation. She puts fertilizer on row 1 but does not put fertilizer on row 2. Both rows receive the same amount of water and light intensity. She checks the growth of the corn over the course of 5 months. What is a constant in this experiment. A.Amount of water B.Corn without fertilizer C.Corn with fertilizer D.Plant height

31 Practice: Identifying Variables Two different rose bushes are grown in a greenhouse for three months. They are given 50 ml of water and receive direct sunlight for 8 hours each day. The number of flowers on each bush is counted at the end of the experiment. Independent Variable? Dependent Variable? Constants?

32 Practice: Identifying Variables One tank of goldfish is fed the normal amount of food once a day, a second tank is fed twice a day, and a third tank four times a day during a six week study. Each tank contained two goldfish and they were all fed from the same source of food. Each morning the fish in each tank were weighed. Independent Variable? Dependent Variable? Constants? Control?

33 Step 5: Analyze Data Data information gained from observations. 2 Types: 1.Qualitative Data collected using your senses QUALITY Texture, color, shape, sound 2.Quantitative Data collected using specific tools of measurement QUANTITY # Mass, length, volume, time

34 Step 5: Analyze Data Take accurate measurements Create graphs/tables Graphs show relationships between variables Serendipity occurrence of accidental or unexpected but fortunate results.

35 Practice: Qualitative Vs. Quantitative Circle Qualitative Data and Underline Quantitative Data. Green 100mL Liquid Weight = 5 lbs Sticky Tastes like watermelon Density is 1.5g/mL Odor smells like eggs

36 Practice: Qualitative Vs. Quantitative Circle Qualitative Data and Underline Quantitative Data. Blue/Green Color Weighs 8 lbs Masterful Brush Strokes Peaceful country scenery Cost $300 Picture is 10 X 14 Smells old and musty With Frame is 14 X 18 Textured brush strokes Surface Area = 140 square inches

37 Graphs 1. Line graph continuous quantitative (#) data Direct variation - both variables increase together or both variables decrease together Inverse variation one variable increases & one decreases

38 Graphs 2. Bar graph non-continuous data that is categorical (counting) 3. Circle graph shows a relationship among parts of a whole (%)

39 Step 6: Draw Conclusion Data does not PROVE anything it either supports or does not support the hypothesis Support hypothesis accepted publish findings Not-support hypothesis rejected & create new hypothesis Repeat experiment!

40 Scientific Method 6 steps

41 Theory and Law Scientific Theory - explanation based on knowledge gained from many observations. Can change Explain Laws Scientific Law 100% true statement about what happens in nature Principles

42 Lab Safety Page xxxi in your textbook has these symbols and their definitions Please copy the names but not the symbols into your notes! Safety Symbol logo designed to alert you about a specific danger.

43 Metric System

44 Standards Standards are exact quantities used to compare measurement. Measurements should include a number & unit. Is the length of your foot a good measurement standard?

45 Metric System Metric System units with divisions that are powers of 10. SI - standards that are universally accepted and understood by scientists throughout the world. Meter length Gram mass Liter volume Second time

46 Metric System Prefix Symbol Conversion Factor Kilo- k 1000 Hecto- h 100 Deka- da 10 BASE (gram, meter, liter) (g, m, L) 1 Deci- d.1 Centi- c.01 Milli- m.001

47 Metric System King Henry Died By Drinking Chocolate Milk Largest Smallest Prefix Kilo Hecto- 100 Deka- 10 BASE (g, m, L) - 1 Deci-.1 Centi-.01 Milli-.001

48 Conversions King Henry Died By Drinking Chocolate Milk Largest Smallest To convert to a larger unit, move decimal point to the left. To convert to a smaller unit, move decimal point to the right.

49 Practice 100 ml = L King Henry Died By Drinking Chocolate Milk

50 Practice 47.9 hg = dg King Henry Died By Drinking Chocolate Milk

51 Practice.23 m = dm King Henry Died By Drinking Chocolate Milk

52 Practice 55 cg = kg King Henry Died By Drinking Chocolate Milk

53 Practice 1) 7 hm = mm 2) 120 m = cm

54 Practice 3).015 dag = hg 4) 5,015 kl = ml

55 Practice 5) 81.5 g = kg 6) 10 cl = L

56 Practice 7).005 cg = dg 8) 920 km = m

57 Practice 9) 41 hl = ml 10) hg = kg

58 Precision and Accuracy Precision is how close your results are to each other. Accuracy is how close your results are to actual/accepted results.

59 Precision and Accuracy

60 Precision and Accuracy

61 Measuring Temperature #1 #2 #3 #4

62 Measuring Liquid Volume A meniscus is a curve in the surface of a liquid. Measurement taken at the bottom of the meniscus.

63 Measuring Liquid Volume #1 #2 #3

64 #1 Measuring Mass #2

65 Measuring Distance #1 #2 cm #3 cm

66 Lab Equipment

67 1. Triple beam balance 2. Electronic balance 3. Beaker 4. Bunsen burner 5. Flint striker 6. Erlenmeyer flask 7. Evaporating dish 8. Filter paper 9. Forceps 10. Graduated cylinder 11. Funnel 12. Hand lends 13. Hot plate 14. Meter stick/ruler 15. Stop watch 16. Microscope 17. Microscope slide 18. Wood splints 19. Lab apron 20. Safety goggles 21. Gloves 22. ph paper 23. Pipettes 24. Droppers 25. Petri dish 26. Ring stand 27. Ring clamp 28. Ring stand test tube clamp 29. Stirring rod 30. Chemical scoop 31. Test tube stopper 32. Test tube 33. Test tube holder 34. Test tube brush 35. Test tube rack 36. Thermometer 37. Tongs 38. Watch glass 39. Spot plate 40. Wire gauze

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