The Nature of Science

1. The Nature of Science Measurement

2. SN#3What is Measurement in Science? • Measurement using scientific tools is important because scientific tools are objective-while our own senses are subjective. There are several physical properties which are measured using specific scientific tools.

3. Mass-how much matter an object. Tool = balance; unit is grams • Weight – measure of gravitational pull on an object. Tool = scale; unit is Newtons N • Volume: How much space an object takes up. Tool = graduated cylinder; unit cm3 = ml • Temperature: average kinetic energy measured with a thermometers; unit C centigrade • Density: how much mass per volume is present. This is measured by dividing the mass by the volume. The unit for density is g/ml or g/ml. • Distance – how far apart items are measured with a metric ruler; unit meters • Accuracy- How close you are to the actual measurement • Precision – How exact and consistent the measurement is.

5. Left Hand Assignment: page 8 Over/Under Estimate yourself 1. Draw a table like the one on the board on page 8. 2. Copy items listed below in the first column. 3. * Mass – Highlighter * Length – your arm * Volume – Box * Length - foot * Volume – in the cup * Height – Lab Counter * Temp – room * Height - Door * Width – Door * Height - You * Mass – 4 pieces of * Temp – water in fish Laffy Taffy tank 4. Estimate the measurement of the item in the 2nd column. Make sure you use the proper unit of measure (cm, ml, cm , C, g) 3 0

6. Accurately measure the items you just gave an estimate for in the third column of the chart. Calculate the difference between your estimate and the actual measurement in the 4th column. Item Est. Meas. Diff.

7. The Nature of Science Scientific Process

8. SN#4 What is the Scientific Process? • The scientific process is a way to make and answer scientific questions by making observations and doing experiments.

9. Steps in the Scientific Process: • Observation: gather information about an event through the senses and scientific tools. These lead to scientific questions. • Questions: Problem, Questions in science are not answered yes or no. • Hypothesis: A testable possible solution to a scientific question. • Material & Procedures: What is needed to do the experiment and the directions for the experiment • Results: Data • Data Collection (Data Table) • Data Display (Graph usually a line graph) • Analysis: Explains the data display • Conclusion: Communicate the results in terms of the hypothesis

11. SN#5 What are scientific observations, questions, and hypotheses? • Observation: An observation is a gathered through the senses and scientific tools – observations lead to scientific questions.

12. TWO TYPES OF OBSERVATIONS(No Notes) • Qualitative • Descriptions of sights, sounds, smells, and textures • Ex. – round, smooth, rough, green, pleasant smell

13. Quantitative • Descriptions that are expressed in numbers • Ex. – expressions of time, temperature, distance, mass, and volume

18. Making an Inference • An inference is a statement or conclusion that is made from observations of something. • We make inferences all the time, and you’d be surprised to know that you are pretty good at it.

23. Mr. Fishy • Write 2 observations about Mr. Fishy on pg 12

24. Questions: A question in science asks about the relationship between events; and are not answered yes or no.

25. Mr. Fishy • Write 2 questions based on your observations about Mr. Fishy on pg 12

26. Hypothesis – A testable possible solution to a scientific question. We will use the “if…then…” format to write the hypothesis. Hypotheses must be written in scientific language. Do not use personal pronouns. • Change: My hypothesis to The hypothesis

27. Lead To Inferences Hypotheses The “guesses” you have about the cause of something (inferences) lead to the possible explanations about why it happened (hypotheses).

28. Writing a GOOD Hypothesis (no notes) • ALWAYS write a hypothesis using this method … IF … then … If I study for my Science quiz, then I should make a good grade

29. QUESTION: HOW DOES FERTILIZER AFFECT TOMATO PLANT GROWTH? Hypothesis: If fertilizer is used then the plant will produce more tomatoes.

30. QUESTION: HOW DOES VITAMIN C HELP PREVENT COLDS?

31. Hypothesis • If you take vitamin C then you will make it through the day and won’t get sick.

32. Question: • Which produces higher grades on science tests, studying with music on, or studying with quiet conditions?

33. Hypothesis • If I study quietly then I will get a higher grade on my test.

34. Mr. Fishy • Write a hypothesis about Mr. Fishy on page 12

35. SN#6 Materials, Procedures, Experiments. • Materials: Specific list of materials needed to conduct an investigation; must give the number of items needed as well as the type. • Example: Two 50ml graduated cylinder  • Procedures: Numbered list of directions for an investigation must start with a verb. • gather materials • measure 50 grams of salt

36. Experiment • A procedure to test the hypothesis. Variable – factor in the experiment that is being tested

37. A good or “valid” experiment will only have ONE variable!

38. Scientific Experiments Follow Rules An experimenter changes one factor and observes or measures what happens.

39. SN#7 Variables, Results, Data • Glue down note page on pg 17

40. The Control Variable The experimenter makes a special effort to keep other factors constant so that they will not effect the outcome. Those factors are called control variables.

41. What is the Purpose of a Control? Controls are variables that DONOT being tested or receiving experimental treatment. Controls are used for COMPARISON Constants are the factors that are kept the same.

42. Other Variables • The factor that is changed is known as the independent variable. • The factor that is measured or observed is called the dependent variable.

43. Identifying Variables • There are 3 types of variables: • Independent Variable (Changed) • Dependent Variable (Measured) • Control

44. IV VS. DV(No Notes) • Independent variable • Also called the manipulated variable • What YOU control and change during an experiment • X-axis • Comes after the word if in the hypothesis • Dependent Variable • Also called the responding variable • Changes because of the IV • What you measure in an experiment • Y-axis • Comes after they word then in the hypothesis

45. Example of Controls & Variables For example, suppose you want to figure out the fastest route to walk home from school. You will try several different routes and time how long it takes you to get home by each one. Since you are only interested in finding a route that is fastest for you, you will do the walking yourself.

46. What are the Variables in Your Experiment? Varying the route is the independent variable The time it takes is the dependent variable Keeping the same walker throughout makes the walker a control variable.

47. One more thing… it is best to make several trials with each independent variable.

48. Results • In the scientific process, data is recorded and kept in the data table. • Data from the data table is then displayed in a graph.

49. SN#8 How is data displayed?Pg 19 • Graphs are used to visually represent data. • Bar Graphs are used for comparison  • Line graphs show relationships between variables. When in doubt use a line graph. • All graphs must be labeled – • Bar and line graphs must be labeled with • Title • Independent variable on x-axis • Dependent variable on y-axis

50. **Use this to help you remember where to place the different types of variables and data. DV y IV x