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

- a way of thinking, observing, and “knowing”

- explanations based on evidence, not belief

- not concerned with pseudoscience's:

Alchemy

UFO’s

Astrology

1. Provide natural explanations for events in the natural world.

2. Aims to use explanations to understand patterns in nature and make useful predictions about natural events

1. Make an observation and ask questions

2. Infer and form a hypothesis

3. Gather materials and design experiment

4. Observe and record data

5. Analyze the data

6. Make a conclusion

Repeat experiment until data is consistent!!

Observation = noticing and describing events

Inference = logical interpretation of what you already know

Hypothesis = explanation for a set of observations

- hypothesis are the bases of scientific theories

Data = results of experiment

•qualitative (description) or quantitative (number)

All experiments must be controlled!!

Controlled experiment = experiment in which only ONE variable at a time.

- variables are factors that can change in the experiment. Two kinds:

1. Manipulated/Independent (deliberately changed)

2. Responding (changes in response to the manipulated variable)

Experiments have two groups, a control group and experimental group.

Experimental group : one variable changed, usually the variable that is being tested.

Control group: exposed to same conditions as the experimental group except variable being tested. (may get Placebo Effect)

Need control in experiments so results can be compared to the normal conditions!!

Observing and Asking Observing and Asking Questions Questions

Scientific investigations begin with Scientific investigations begin with observationobservation, the act of noticing and , the act of noticing and describing events or processes in a careful, describing events or processes in a careful, orderly way. orderly way.

For example, researchers observed that For example, researchers observed that marsh grass grows taller in some places than marsh grass grows taller in some places than others. This observation led to a question: others. This observation led to a question: Why do marsh grasses grow to different Why do marsh grasses grow to different heights in different places?heights in different places?

Inferring and Forming a Inferring and Forming a Hypothesis Hypothesis

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

Designing Controlled Designing Controlled Experiments Experiments

The researchers added nitrogen fertilizer (the The researchers added nitrogen fertilizer (the independent variable) to the experimental independent variable) to the experimental plots. They then observed the growth of plots. They then observed the growth of marsh grass (the dependent variable) in both marsh grass (the dependent variable) in both experimental and control plots.experimental and control plots.

Collecting and Analyzing DataCollecting and Analyzing Data

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

Collecting and Analyzing Data Collecting and Analyzing Data

Quantitative data are numbers obtained Quantitative data are numbers obtained by counting or measuring. In the marsh grass by counting or measuring. In the marsh grass experiment, it could include the number of experiment, it could include the number of plants per plot, plant sizes, and growth rates. plants per plot, plant sizes, and growth rates.

Collecting and Analyzing Data Collecting and Analyzing Data

Qualitative data are descriptive and Qualitative data are descriptive and involve characteristics that cannot usually be involve characteristics that cannot usually be counted. In the marsh grass experiment, it counted. In the marsh grass experiment, it might include notes about foreign objects in might include notes about foreign objects in the plots, or whether the grass was growing the plots, or whether the grass was growing upright or sideways.upright or sideways.