THE NATURE OF LIFE



1-1 THE Scientific Method

[pic]  The goal of science;

• To investigate and understand the natural world, to explain events in the natural world, and to use those explanations to make useful predictions.

Science;

• is an organized way of using evidence to learn about the natural world

1-2 THE Scientific Method

Observation

-using one or more of the __senses____ to collect information (data).

Inference

- a logical __conclusion_____ based on prior experience or knowledge

Data

- information gathered from observations using our senses, usually in the form of a ____measurement______

Hypothesis

- a testable prediction

-the process of developing a possible ____answer ______ to a problem or question.. In the form of an “ If……, then” statement.

Ex.: If Miracle Grow fertilizer is added to the tomato plants, then they will grow bigger in mass.

Scientific Method

– steps used to ____investigate_________ questions

Controlled Experiment

- Series of test or trials used to test a hypothesis

- A controlled experiment always has two groups:

1) Experimental group – this is the group that _ receives some sort of treatment__

2) Control Group – this is the group that _gets no treatment or a placebo____

We need both groups so that we can compare them. If we only had an experimental group we would not really know if our treatment had an effect.

. What do scientists do?

Steps of the Scientific Method

1. Ask Questions- that can be tested and answered through experiments

2. Make Observations- Using tools (ex. Microscope, ruler, balance)

or senses

3. Make Inferences- ideas based on observations

4. Experiment- Create a hypothesis – prediction that can be tested

-experiment either supports or not support hypot

5. Collect Data – During experiment -organized in a data table, graph, chart, diagram, etc.

6. Draw Conclusions- Decide if data sup ports hy p othesis or not

7. Repeat- experiment several times to be sure of results. The more trials or samples the less chance for an error

8. Peer Review- publish results so that other scientists can repeat and review the experiment and conclusions

Experimentation

- controlled experiment is used to test a hypothesis.

- A good controlled experiment must have

1) Control Group – used as a

__comparison for experimental group____________ .

2) Experimental Group – differs from the control by one variable (the group that _ receives the treatment ___ or factor being tested.

3) __Only Independent variable________ is tested . All other variables are controlled.

4) A sufficient number of test subjects. The __more accurate ___ the results.

5) Publish the results.

Variables

There are ___3____ types of variable in a controlled experiment

Independent Variable

– The __thing_________ you manipulate or change ( amt of water, fertilizer, temperature or time at which you collect or measure the data)

Dependent Variable

– what ___you measure or count__________ in the experiment.

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Dependent

-what is measured or counted

-responds to what is changed in the independent variable

- ex. how tall, how many, what mass

Independent

- what the experimenter changes or chooses

- ex. time interval (when to measure), the amount of fertilizer, pH, temperature, amount of light, concentration of salt, etc

Controlled

- all the other things that can influence the results of an experiment.

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