The Nature of Science Biology 20

What is Science? Story arranging activity An activity devoted to making sense out of events in the natural world that often seem unrelated and confusing. In science, what we claim to know depends on connections between what we observe and what we think we already know.

Essential Skills to Experimentation In every experiment there is always a control group and experimental group. What is the difference? Vs. Experimental Group Control Group

Essential Skills: Variables Most scientific experiments have a specific set of variables. These are: Manipulated variable Responding variable Controlled variables

Essential Skills: Variables Manipulated Variable – The variable that is being “tested” Responding Variable – The results Control Variable – Factors that need to stay the same smoking Level of health Age, sex, # of people, health, exercise, diet, length of time, type of smokes, amount smoked.

Essential Skills: Hypothesis and Prediction An hypothesis is an educated prediction according to a known scientific concept. An hypothesis must be testable. On the other hand, a prediction is a statement about the way things will happen in the future, often but not always based on knowledge or experience. The hypothesis should fulfill the following three conditions: Directly answer the problem or research question by proposing a relationship between the independent and dependent variables. Give a reason or explanation for the answer according to a scientific concept It must be testable.

Essential Skills: Evidence (Data Collection) Types of Data: Qualitative data \ Quantitative data Vs.

Qualitative vs. Quantitative Qualitative data - Uses descriptions or words Observed with the senses Examples: Quantitative data Uses direct measurements Determined using an instrument or by counting Examples: Qualitative Data: Examples: colour or appearance (reddish-gray, brown, gold, metallic, bright, dull); texture (soft, rough, smooth, hard, gritty); odour (sweet-smelling, flowery, putrid); taste (sour, sweet, salty, bitter); sound (loud, soft, whistling) Quantitative Data: Examples: length/width or distance (15.0 cm, 45.3 m, 8.56 km); mass (30 kg, 5.67 g); direct count (134 cells, 89 people) – Anything with a number!!

Essential Skills: Data Analysis Data collected is generally manipulated, transformed and presented in a form suitable for evaluation Analysis of data includes: Graphs Tables Labeled drawings

Line Graph Used when time is the manipulated variable Bar Graph Used for comparisons (categories of data)

Rules for Graphing Rule # 1: The title of the graph is written across the top of the graph paper. It is stated to indicate the relationship between the manipulated variable and the responding variable. The word "versus” should not be included.

Rules for Graphing Rule #2: On the horizontal axis place the name of the manipulated variable and its unit of measure. Rule #3: 3. On the vertical axis place the name of the responding variable and its unit of measure.

Rules for Graphing Rule # 4: Calculate the values for the scales so the plotted data extends over most of the graph. All plotted points must fit on the graph paper. Rule # 5: In most cases the scales should start at zero. If not, use the zigzag at the start of the axis Y Responding Variable X Manipulated variable

Rules for Graphing Rule # 6: Plot the coordinate points for the manipulated and responding variables on the graph and connect the dots.

Rule #7: If you are plotting two or more variables, a legend should be placed in the lower right corner of the graph. The legend should identify each of the lines on the graph.

Practice Questions: Y X Line Y X Bar For each of the following decide which of the variables would be placed on the x axis and which would be placed on the y axis. A. You keep track of the average price of gas per week over a one year period. (____) average price of gas per week (____) week What type of graph would work best to show the trend of gas prices? _______________ B. You measure the amount of toxin found in various animals found in the Pacific Ocean. (____) amount of toxin (____) type of animal What type of graph would work best to show amount of toxin is animals? ____________ Y X Line Y X Bar

The Scientific Method The Scientific Method What is the correct order of steps in the Scientific Inquiry Method? 1. Problem 2. Hypothesis 3. Experimentation 4. Conclusion

The Scientific Method The Scientific Method