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UNIT 1. SCIENTIFIC METHODS. What is Science?. Science is a way of learning about the natural world and the knowledge gained through that process. Scientific Inquiry is the diverse ways in which scientists explore problems and seek to answer questions. Scientific Methods.
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UNIT 1 SCIENTIFIC METHODS
What is Science? • Science is a way of learning about thenatural world and the knowledge gained through that process. • Scientific Inquiry is the diverse ways in which scientists explore problems and seek to answer questions.
Scientific Methods Scientific methods generally include: • asking questions • making observations and inferences • developing hypotheses • designing and conducting experiments • collecting and interpreting data • drawing conclusions
Many of the scientific methods are skills that you already use for day to day activities. • Observation: involves using your senses-sight, hearing, smell, taste, and touch. An observation is based on facts. Ex.- the shirt is blue. • Inference: an interpretation based on your observation and prior knowledge. Ex- the liquid in the beaker must be milk because it is white.
Scientists seek answers through experimentation • Based on their previous knowledge, observations, and inferences, scientists design an experiment to test what will happen. • Their guess of what will happen in the experiment is called the hypothesis.
Suppose we want to know what in type of soil a plant will grow better. • We need at least 2 plants so that we will be able to compare the growth.
Why is this experiment not a fair comparison? http://www.pnm.com/sciencefair/answer.htm
You don’t know if the difference in growth is from the different fertilizer (A or B) or the different soil (sandy or clay) You can only test for 1 thing different at a time.
The one thing that is different between the groups in an experiment is the: Independent variable: also called the manipulated variable or the experimental variable This is the variable that is being tested. Ex. Type of soil such as sandy or clay
The results of the experiment may show another difference between the groups called the: Dependent variable also known as responding variable. When planning an experiment, choose a dependent variable that can be measured.
For example: Look again at our plant experiment. What differences between the plants can be measured?
Height of the plants • Number of leaves Can be measured • Growing “better” can NOT be measured!
A possible hypothesis for this experiment could have been: Plants grown in clay soil will grow taller than those grown in sandy soil. Can you think of some other possible hypotheses for this experiment?
Plants grown in clay soil will have more leaves than those grown in sandy soil. Plants grown in sandy soil will grow taller than those grown in sandy soil. Plants grown in sandy soil and clay soil will not have any measurable differences.
Notice that each hypothesis includes: the independent variable and the dependent variable Lets go back and pick those out.
Plants grown in clay soil will grow taller than those grown in sandy soil. Dependent variable Independent variable Independent variable
Data • The facts, figures, and other evidence gained through observation. Often involves measurements. • Data can be displayed on a chart or graph, or both.
Charts and graphs • Plant 1 Plant 2 wk1 Wk 2
D E P E N D E N T INDEPENDENT
Conclusion • Once scientists have reviewed their data , they are ready to draw a conclusion. The data will reveal if the scientists hypothesis was correct/incorrect. Sometimes a conclusion can not be reached and more data is required.
Scientific Theory • A scientific theory is a well tested scientific concept that explains a wide range of observations. An accepted theory has withstood repeated tests.
