Introduction to Biology and Homeostasis

Section 2Scientific Processes

BiologyFall 2010

Bell Ringer

1. Why do you think following the process of the scientific method is important?

2. What would be the implications of doing experiments without the scientific method?

Objectives

• Describe the stages common to scientific investigations

• Distinguish between forming a hypothesis and making a prediction

• Differentiate a control group from an experimental group and an independent variable from a dependent variable

• Define the word theory as used by scientists

Solving Scientific Puzzles

• _____________ : the act of noting or perceiving objects or events using the senses

• Even though scientists may expect certain results, they do not form __________ until they have enough evidence to support them

Stages of Scientific Investigation

• No single “_____________ ”• Scientific investigations tend to have common

stages: – Collecting observations– _____________________– Forming hypotheses and making predictions – Confirming predictions (with controlled

experiments)– Drawing _________________

Collecting Observations

• Core of scientific investigation

Asking Questions

• Observations of the _____________________ often raise questions

Forming Hypotheses and Making Predictions

• ____________ : is an explanation that might be true, a statement that can be tested by _____________ or experimentation – Educated guess based on what is already known

• ___________ : is the expected outcome of a test, assuming the hypothesis is correct

Confirming Predictions

• Design an experiment to ______ predictions and hypotheses

• ____________ : a planned procedure to test a hypothesis

• ____________ : is a group in an experiment that receives no experimental treatment

Confirming Predictions

• The control and experimental groups are designed to be identical except for one factor or variable

• The factor that is changed in an experiment is called the __________ variable

• The variable that is measured in an experiment is called the _________ variable

Drawing Conclusions

• Once data are ________ and _________, a conclusion is made as to whether the data ________ the hypothesis

• The hypothesis may be _________ or ___________

• A hypothesis may be supported but never proven because another experiment with new data and new information may alter the conclusion

Scientific Explanations• It is important in science not to be misled by an isolated

observation • ________ : is a set of related hypotheses that have been

tested and confirmed many times by many scientists – A theory unites and explains a broad range of observations – Provides an explanation

• _______: generalizes a body of observations. – At the time it is made, no exceptions have been found to a law. – Scientific laws explain things, but they do not describe them

Theory vs. Law

Constructing a Theory

• Involves considering ____________ and _________________

• Key requirement of valid scientific research is that it can be replicated by others

• ________ : represents that in which they are most certain, well-supported scientific explanation that makes useful predictions

• Always a possibility that theory could be revised with further evidence

Review

• Match the following:Observation Is color influenced by water color?

Asking questions The celery color will change to the color red.

Hypothesis Tall, green

Prediction If the water color is changed the celery color will change.

Review

• Match the followingExperiment Celery in normal water.

Control Group Celery color.

Independent variable Put some stalks of celery in water dyed red, put some stalks of celery in normal water.

Dependent variable The celery in the red water color changed color to red.

Drawing conclusions Red water.