1.1 What Is Science?

Bellwork: Tues. Aug. 14, 2018 1. Arachnophobia:________________ 2. Microcephally: __________________ https://www.youtube.com/watch?v=WrSW2R7dbnE https://www.youtube.com/watch?v=zlu2u1np9d4 Now working backwards…. How would you write: Joint disease: ___________ 4. Study of animals ______________ Hint: a spider is an arachnid

Riddle: What is this called? A “Pokewagon”

Goals of Science to provide natural explanations for events in the natural world. to use those explanations to understand patterns in nature To make useful predictions about natural events.

What Science Is and Is Not Biology is not just a collection of never-changing facts or unchanging beliefs about the world. Science rarely “proves” anything in absolute terms… it is an ongoing process. Remember: Consistent, Observable , Natural Predictable Testable and Tentative from Fridays notes?

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… it is an ongoing process. Scientists aim for the best understanding of the natural world that current methods can reveal.

Science is an organized way of gathering and analyzing evidence about the natural world. 10

Steps in the Scientific Method 1.observation: act of noticing & describing events or processes in a careful, orderly way. (that marsh grass grows taller in some places than others.) 2. question: form questions about the observation: Why do marsh grasses grow to different heights in different places?

After posing questions, scientists use further observations to make: 3. inferences: logical interpretations based on what is known. Prediction: (if the soil has more nutrients, then the grass will grow better) Infer: to figure out – to reason 4. hypothesis: a scientific explanation for observations that can be tested in ways that support or reject it. (Marsh grass grows better with more nutrients – nitrogen) Soil A Soil B

Inferrence: something limits grass growth in some places Inferrence: something limits grass growth in some places. Based on their knowledge of salt marshes, they hypothesized that marsh grass growth is limited by available nitrogen.

Controlling Variables 5. controlled experiment: Only one variable is changed, all other variables are kept unchanged, or controlled. independent variable (or manipulated variable) variable that is changed by experimenter. dependent variable (or responding variable): variable that changes in response to the independent variable

Experiments are divided into control and experimental groups. control group: exposed to the same conditions as the experimental group except for one independent variable. Scientists set up several sets of control and experimental groups to try to reproduce or replicate their observations.

Researchers selected plots of marsh grass with similar plant density, soil type, input of freshwater, and height above average tide level, and divided them into control and experimental groups. Then they added nitrogen fertilizer (the independent variable) to the experimental plots, and observed the growth of marsh grass (the dependent variable) in both experimental and control plots.

Scientists record experimental observations, gathering information called data. There are two main types of data: quantitative data and qualitative data.

6. Collecting and Analyzing Data Quantitative data: numbers obtained by counting or measuring: number of plants per plot, plant sizes, and growth rates. Qualitative data: descriptive  characteristics that cannot usually be counted. Like: grass growing upright or sideways.

Data can be organized into graphs This graph shows how grass height changed over time. The independent variable is always placed on the X axis. The dependent variable is always placed on the Y variable.

Analysis showed that marsh grasses grew taller than controls by adding nitrogen.

Sources of Error Researchers must be careful to avoid errors in data collection and analysis. Tools used to measure the size and weight of marsh grasses, for example, have limited accuracy. Data analysis and sample size must be chosen carefully. The larger the sample size, the more reliable the data. .

7. Drawing Conclusions: Scientists use experimental data as evidence to support, reject, or revise the hypothesis being tested, and to draw a valid conclusion. New data may indicate researchers have the right idea but are wrong about a things – so the hypothesis is revised, predictions made, and new experiments are designed.

Hypotheses may have to be revised and experiments redone several times before a final hypothesis is supported and conclusions can be drawn.

Scientists never state: “The hypothesis was… right or wrong, instead they say “The hypothesis …. Was either supported or not supported.

Notes: Scientific Method 1. observing 2. asking questions 3. making inferences and predictions (if…then) 4. forming hypotheses 5. conducting controlled experiments 6. collecting and analyzing data 7. drawing conclusions.