Scientific Inquiry What is Science?

 A body of knowledge  A set of theories that describes the world  A way of learning about the world  A method to answer questions about the natural world

How do Scientists Learn About the World? 1.Ask a question 2.Make a prediction 3.Test the prediction 4.Compare results to the prediction 5.Make a conclusion 6.Hypothesis is either rejected, or supported

The Scientific Method-ask a question  Only questions which can be answered through experiments.  Examples of good scientific questions:  How does the amount of nitrogen fertilizer affect the height of pea plants?  Does increasing the temperature of an enzyme increase its rate of reaction?

Write a Good Scientific Question.    

Scientific Method-make a prediction  Make a prediction  A scientists prediction about the results of an experiment is called the hypothesis  The hypothesis must be testable and specific and always written as a statement  Hypotheses usually begin with “I think that……” or “If…………then…………”  Example: I think that the more fertilizer that a pea plant gets, the taller it will grow

Scientific Method-test the prediction  Controlled Experiments  Used by Scientists to test their hypothesis  Always have at least two groups:  Control Group- stays the same  Experimental Group- changes, receives some sort of treatment

How are the control group and the experimental group different? 1. 2.

Scientific Method- compare results  Scientists analyze the data collected  Data is information  Compare the data from the control group with the experimental group  Use statistics to see if there is significant difference  Example- the pea plants in the experimental group grew an average of 18.3cm, while the control group grew an average of 12.6cm

Scientific Method- make a conclusion  Examine data, charts, graphs, to determine if the hypothesis is supported or rejected  Could the differences be due to chance?  Use statistics to tell

Scientific Method- hypothesis rejected or supported?  If supported, repeat experiment to see if it is valid ( able to be repeated with the same results)  If rejected, then come up with a new hypothesis and experiment, repeat the process

Controlled Experiments- variables  Three types of variables:  Independent- the thing that is different between the experimental and control group  Dependent- the data you collect as your experiment progresses, depends on the independent variable  Controlled- remains the same

I set up an experiment with 30 pea plants. I give 10 plants no fertilizer, 10 plants 5g. of fertilizer, and 10 plants 15g. of fertilizer. After 14 days I measure the height of the plants.  What is the independent variable?  The amount of fertilizer  What is the dependent variable?  The height of the pea plants  What are the 2 controlled variables?  The amount of soil and water  What is the control group?  Plants with no fertilizer  What is the experimental group?  The two groups of plants getting fertilizer

What makes a good experiment?  Large number of samples  Only one independent variable  Validity  Conclusions based on evidence  Is based on fact, not opinion

Design an Experiment !  Think of an experiment to test the hypothesis that sleeping more than 8 hours a night improves a students grades on Science quizzes!  Control group:  Experimental Group:  Independent Variable:  Dependent Variable:  Controlled Variables: