What is Science?

1. What is Science? • Science is a system of knowledge based on facts and principles

2. Natural Science

3. Natural Science is: • Natural Science is the general branch that all the other sciences belong. • It deals with phenomenon from what we would call our natural universe.

4. How does all of this take place?

5. By Observations • Scientist make observations using their senses and technology. • Sometimes the technology does not exist to make the needed observations.

6. What is Technology?

7. Technology • Technology is the application of science to meet human needs. • Can be misused.

8. Scientist investigate

9. Scientist Observe • Paying close attention to details scientist look for connections and patterns in nature. She is watching or observing you!

10. Using Scientific law Scientific law is a summary of an observed natural event Using Scientific Theory Scientific theory is a tested possible explanation of a natural event Scientist also Experiment

11. Scientific Theory must: • Explain observation simply and clearly. • Experiments must illustrate the theory and be repeatable. • Be able to predict from the theory.

12. Make-up of Scientific Law • Laws just summarize observations about nature or a natural event. • Laws do not explain how or why something happens.

13. Critical Thinking • Applying logic and reason to observations and conclusions.

14. Scientific Method This is what Science is. Scientific Method Not science vid Intro. CYU Chapter 1 Part I 1-12

15. Problem

16. To solve the problem • You ask a question. • You may gather data. • You form ahypothesis; a possible answer that you can test in some way. Can be a “if” , “then” statement but not always. • Hypothesis.ppt

17. Testing Hypotheses • Scientist test hypothesis by doing experiments. • Good experiments test only one variable at a time. Variable is anything that can change in an experiment. (Many variables exist in this picture.)

18. How does it measure up?

19. Chapter One: Measurement • 1.1 Measurements • 1.2 Time and Distance • 1.3 Converting Measurements • 1.4 Working with Measurements

20. A measurementis a determination of the amount of something. A measurement has two parts: a number value and a unit 1.1 Measurements

21. 1.1 Two common systems • The English System is used for everyday measurements in the United States. • Miles, yards, feet, inches, pounds, pints, quarts, gallons, cups, and teaspoons are all English system units. • In 1960, the Metric System was revised and simplified, and a new name was adopted—International System of Units.

22. 1.1 International System of Measurement (SI) • The acronym SI comes from the French name Le Système International d’Unités. • SI units form a base-10 or decimal system. • In the metric system, there are: • 10 millimeters in a centimeter, • 100 centimeters in a meter, and • 1,000 meters in a kilometer.

23. 1.1 The meter stick • A meter stick is 1 meter long and is divided into millimeters and centimeters.

24. 1.1 The meter stick • Each centimeter is divided into ten smaller units, called millimeters. What is the length in cm?

26. 1.2 Time and Distance • Two ways to think about time: • What time is it? • How much time? • A quantity of time is also called a time interval.

27. 1.2 Time • Time comes in mixed units. • Seconds are very short. • For calculations, you may need to convert hours and minutes into seconds. How many seconds is this time interval?

28. 1.2 Distance • Distance is the amount of space between two points. • Distance is measured in units of length. • The meter is a basic SI distance unit. In 1791, a meter was defined as one ten-millionth of the distance from the North Pole to the equator. What standard is used today?

29. 1.2 Metric prefixes • Prefixes are added to the names of basic SI units such as meter, liter and gram. • Prefixes describe very small or large measurements.

30. 1.3 Converting units • To convert 1,565 pennies to the dollar amount, you divide 1,565 by 100 (since there are 100 pennies in a dollar). • Converting SI units is just as easy as converting pennies to dollars.

31. Solving Problems • Convert 655 mm to m • Looking for: • …the distance in meters • Given: • …distance = 655 millimeters • Relationships: • Ex. There are 1000 millimeters in 1 meter • Solution: 655 mm = .655 meters

32. Solving Problems Convert 142 km to m • Looking for: • …the distance in meters • Given: • …distance = 142 kilometers • Relationships: • Ex. There are ? meters in 1 kilometer? • Solution: • Use the conversion tool.

33. Solving Problems Convert 754,000 cm to km • Looking for: • …the distance in kilometers • Given: • …distance = 754,000 centimeters • Relationships: • Ex. There are ? cm in 1 m? • There are ? m in 1 km? • Solution: • Use the conversion tool.

34. 1.3 Converting units • A conversion factor is a ratio that has the value of one. • This method of converting units is called dimensional analysis. • To do the conversion you multiply 4.5 feet by a conversion factor.

35. Solving ProblemsUsing Ty-Fighters ppt Convert 4.5 ft to cm • Looking for: • You are asked for the distance in cm • Given: • You are given the distance in ft. • Relationships: • Ex. There are ? cm in 1 ft? 30.48 cm = 1 ft • Solution: • Make a conversion factor from equivalent

36. 1.3 Converting units • Use the correct conversion factor to convert: • 175 yds. to m. • 2.50 in. to mm.

37. 1.4 Working with Measurements • Accuracy is how close a measurement is to the accepted, true value. • Precision describes how close together repeated measurements or events are to one another.

38. 1.4 Working with Measurements • In the real world it is impossible for everyone to arrive at the exact same true measurement as everyone else. Find the length of the object in centimeters. How many digits does your answer have?

39. 1.4 Working with Measurements Digits that are always significant: • Non-zero digits. • Zeroes between two significant digits. • All final zeroes to the right of a decimal point. Digits that are never significant: • Leading zeroes to the right of a decimal point. (0.002 cm has only one significant digit.) • Final zeroes in a number that does not have a decimal point.

40. Solving Problems What is area of 8.5 in. x 11.0 in. paper? • Looking for: • …area of the paper • Given: • … width = 8.5 in; length = 11.0 in • Relationship: • Area = W x L • Solution: • 8.5 in x 11.0 in = 93.5 in2 # Sig. fig = 94 in2

41. 1.4 Working with Measurements • Using the bow and arrow analogy explain how it is possible to be precise but inaccurate with a stopwatch, ruler or other tool.

42. 1.4 Resolution • Resolution refers to the smallest interval that can be measured. • You can think of resolution as the “sharpness” of a measurement.

43. 1.4 Significant differences • In everyday conversation, “same” means two numbers that are the same exactly, like 2.56 and 2.56. • When comparing scientific results “same” means “not significantly different”. • Significant differences are differences that are MUCH larger than the estimated error in the results.

44. 1.4 Error and significance • How can you tell if two results are the same when both contain error (uncertainty)? • When we estimate error in a data set, we will assume the average is the exact value. • If the difference in the averages is at least three times larger than the average error, we say the difference is “significant”.

45. 1.4 Error • How you can you tell if two results are the same when both contain error. • Calculate error • Average error • Compare average error

46. Solving Problems Is there a significant difference in data? • Looking for: • Significant difference between two data sets • Given: • Table of data • Relationships: • Estimate error, Average error, 3X average error • Solution: • Math answer: 93.5 in2 • Determine # of significant figures = 94 in2