Chapter One: The Nature of Science

1. Chapter One:The Nature of Science 1.1 What is Science? 1.2 Science in Context 1.3 Studying Life

2. What are the GOALS of SCIENCE??? • Provide natural explanations for events in the natural world. • Use those explanations to… • understand patterns in nature • make useful predictions about natural events

3. What SCIENCE is and is not… • Science is an organized way of gathering and analyzing evidence about the natural world • Not just a collection of never-changing facts or unchanging beliefs about the world. • Some scientific “facts” will change soon—if they haven’t changed already • scientific ideas are open to testing, discussion, and revision

4. Science, Change, and Uncertainty • Despite all of our scientific knowledge, much of nature remains a mystery. Almost every major scientific discovery raises more questions than it answers. This constant change shows that science continues to advance. • Learning about science means understanding what we know and what we don’t know. Science rarely “proves” anything in absolute terms. Scientists aim for the best understanding of the natural world that current methods can reveal. • Science has allowed us to build enough understanding to make useful predictions about the natural world.

5. Science as a Way of Knowing • Science deals only with the natural world • natural world - things that have not been substantially altered by human intervention. • Scientists collect and organize information in an orderly way, looking for patterns and connections among events. • Scientists propose explanations that are based on evidence, not belief. Then they test those explanations with more evidence.

6. Scientific Method What do I already know?

7. What do you know about the Process? • Write down what YOU know on your paper by yourself. • With a partner share your information (side by side) • With a group of 4 share your information (square) • Share with the class using the whiteboards

8. Scientific Methodology: • A common misconception among students is that the “scientific method” is a set of five or six steps performed by all scientists, always in the same order. • There isn’t any single, cut-and-dried “scientific method.” • There is a general style of investigation that we can call scientific methodology.

9. Vocabulary: • Inference • Data • Observation • Hypothesis • Theory • Science • Controlled Experiment • Control Group • Independent Variable • Dependent Variable

10. What procedures are at the core of scientific methodology? • Observing and asking questions • Making inferences and forming hypotheses • Conducting controlled experiments • Collecting and analyzing data • Drawing conclusions

11. Observations • Act of noticing and describing events or processes in a careful, orderly way. • Using your senses • What did you see, smell, hear, feel, taste? • Think something that nobody has though yet, while looking at something that everybody sees.” Arthur Schopenhaver philosopher • Leads to questions that no one has asked before

12. Asking Questions and Stating the Problem • What are you investigating? • Examples: • Does light affect the growth of plants?

13. Making Inferences and Forming Hypotheses: Inference Hypothesis A scientific explanation for a set of observations that can be tested in ways that support or reject it. A possible explanation for what you expect to happen Ex. Plants will grow toward a source of light. • A logical interpretation based on what scientists already know.

14. In Your Notebook…… • What is the difference between an observation and an inference? • List an example of each.

15. In Your Notebook…… • An observation is something noticed using the senses. • An inference is a logical interpretation of an observation. Inference Observation • Smell of gas in the hallway • Owl perched in tree • The owl has wings • A science class is doing a lab with Bunsen burners. • Owls live in trees • Owls can fly

16. Sample Problems: • Does ice melt faster in freshwater or salt water? • Does the amount of light received affect plant growth? • Does acid rain have an effect on frog egg development?

17. Sample Hypotheses: • Ice melts faster in freshwater than in salt water. • Plant growth is greater when exposed to more sunlight. • Frog egg development is adversely affected by acid rain (slower growth and increased deformities). • Design an experiment to address one problem (question) Provide a short summary of the procedure. Identify the independent and dependent variable in your experiment.

18. Conducting Controlled Experiments • Only one variable is tested at a time. • Variable = factors that can change • Ex. temperature, light, time, availability of nutrients • All other variables should be kept unchanged or controlled

19. The Variable • Variable – factors that change • Independent variable - variable that is deliberately changed (manipulated variable) • Dependent variable – the variable that is observed and changes in response to the independent variable (responding variable)

20. Control & Experimental Groups • An experiment is divided into control and experiments groups • The control & experimental group have the exact same setup except for the independent variable • Ex. The experimental group grows with light and the control group has no light

21. Identifying Controls and Variables

22. Example #1 Smithers thinks that a special juice will increase the productivity of workers. He creates two groups of 50 workers each and assigns each group the same task (in this case, they're supposed to staple a set of papers). Group A is given the special juice to drink while they work. Group B is not given the special juice. After an hour, Smithers counts how many stacks of papers each group has made. Group A made 1,587 stacks, Group B made 2,113 stacks.

23. Example #2 • Homer notices that his shower is covered in a strange green slime. His friend Barney tells him that coconut juice will get rid of the green slime. Homer decides to check this this out by spraying half of the shower with coconut juice. He sprays the other half of the shower with water. After 3 days of "treatment" there is no change in the appearance of the green slime on either side of the shower.

24. Example #3 • Krustywas told that a certain itching powder was the newest best thing on the market, it even claims to cause 50% longer lasting itches. Interested in this product, he buys the itching powder and compares it to his usual product. One test subject (A) is sprinkled with the original itching powder, and another test subject (B) was sprinkled with the Experimental itching powder. Subject A reported having itches for 30 minutes. Subject B reported to have itches for 45 minutes.

25. Example #4 • Lisa is working on a science project. Her task is to answer the question: "Does Rogooti (which is a commercial hair product) affect the speed of hair growth". Her family is willing to volunteer for the experiment.

26. Collecting and Analyzing Data: Data – detailed records of experimental observations • Quantitative – numbers obtained from counting or measuring • Qualitative – descriptive and involve characteristics that cannot usually be counted • Charts & graphs are tools that help scientists organize their data • The larger sample size = more reliable data

27. Setting up a BAR Graph • Bar Graphs are used for comparison • This bar graph is comparing the overall (end result) height of the grass Dependent Variable Independent Variable

28. Setting up a LINE Graph Adding Nitrogen Dependent Variable Independent Variable

29. Drawing Conclusions • Data is used as evidence to support, refute, or revise the hypothesis being tested • Should connect back to original hypothesis • Hypothesis can be reevaluated and revised • New predictions are made and new experiments designed • It is not always possible to test a hypothesis with an experiment (ex. animal behavior) • Ethics may prevent certain types of experiments, especially on human subjects • Experiments based on what humans were already exposed to

30. OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. PROCEDURE Covered jars Uncoveredjars Controlled Variables: jars, type of meat, location, temperature, time Several days pass Manipulated Variables: gauze covering that keeps flies away from meat Responding Variable: whether maggots appear Maggots appear No maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur. Redi’s Experiment on Spontaneous Generation

31. Communicating Results, Reviewing and Sharing Ideas • Peer review allows ideas to be shared, and to test and evaluate each other’s work • Spontaneous Generation: • Redi Needham  Sapallanzani  Pasteur • Animation of Spontaneous Generation • Ensures accuracy • Sparks new questions and further studies

32. Theory • A well-tested explanation that unifies a broad range of observations and hypotheses • The meaning of the word theory in daily life is different from its meaning in science • A scientific theory is NOT a hunch • A useful theory that has been thoroughly tested and supported may become the dominant view among the majority of scientists • No theory is considered absolute truth • Theory versus a Law • Theory - represent something fundamental about how nature works • Law - can often be reduced to a mathematical statement; based on empirical data • Science is always changing as new evidence is uncovered • Theories can be revised or replaced by a more useful explanation

33. Formative Assessment: • On the index card provided, write at least three sentence that uses the chapter vocabulary terms and clearly shows the relationship between the terms. Index cards will be collected as students exit the classroom. Inference Controlled Experiment Data Control Group Observation Independent Variable Hypothesis Dependent Variable Theory

34. Homework: • Read Sections 1.1 (pgs 4-9) and 1.2 (pgs 10-15); 1.1 Assessment (pg 23) #1-5, 7, 9-12 (write Q & only Answer for Multiple Choice)

35. Characteristics of Living Things What must one possess to be considered living?

36. Based on a Universal Genetic Code • Contain directions for inheritance carried by DNA • Copied and passed from parent to offspring

37. Made of Cells • Smallest unit considered alive • Organized • Can be unicellular(bacteria) or multicellular(plants, animals, fungi) • Can be prokaryotic or eukaryotic cell(s)

38. Vocabulary • Prokaryote- unicellular organism that lacks a nucleus (bacteria) • Eukaryote- unicellular or multicellular organism whose cells contain a nucleus (plant, animal, fungi)

39. Grow and Develop • Pattern of growth and development over time • Growth = increase in amount of material in an organism • Development = series of changes an organism undergoes in reaching its final form

40. Respond to Environment • Organisms constantly need to respond to changes in their surroundings • A stimulus is anything (signal) in an organism’s environment that causes a reaction/response

41. Ability to Reproduce • Sexual reproduction - 2 cells unite to produce a unique offspring • Asexual reproduction – single parent produces an identical offspring

42. Maintain a Stable Internal Environment: • Homeostasis – process by which organisms keep their internal conditions stable • For Example: • Body Temperature • pH • Blood glucose levels • O2 levels

43. Obtain & Use Material and Energy • Take in materials and energy to grow, develop and reproduce • Metabolism –combination of chemical reactions that build up or break down materials while carrying on life processes

44. Vocabulary • Autotroph- organisms that manufacture their own food (plants) • Heterotroph- Organisms that cannot make their own food (humans)

45. As a Group, Change Over Time • Organisms can adapt – that make them suitable to environment • Over generations, groups of organisms evolve, or change over time • Well-adapted individuals survive and reproduce.

46. Adaptation Example

47. Adaptation of a Sloth’s chill pace… • Why do sloths go so very slow? • A clip by David Attenborough looks into the lives of sloths and reveals that their chill pace is actually an adaptation as a result of poor nutrition from their diet of leaves. Rather than eating more for more energy, the sloth simply does less. Click on picture for short video clip on a sloths adaptation BBC Earth – Saying Boo to a Sloth

48. The Metric System What do I already know?

49. Metric System & BASE UNITS • Universal language of scientists • Also known as the International System of Units (SI Units) • Length– meter (m) • Mass– gram (g) • Volume– liter (L)

50. Prefixes kilo hecto deka BASE deci centi milli k h da BASE d c m Metric Prefixes are used before a unit to make it smaller or larger