Biology 1.3 The Scientific Process

Scientific Process  Steps of the Scientific Process 1. Identify the Problem 2. Gather information 3. Form Hypothesis 4. Test the Hypothesis 5. Record observations, collect data 6. Organize and analyze the data 7. State a conclusion: prove or disprove your hypothesis

Scientific Process Identify the problem What is it you need to prove or disprove? State it clearly; usually as a question!

Example  Many people believe that playing classical music to houseplants makes them grow faster!  Is this true? Does playing classical music to houseplants make them grow faster than normally raised plants?

Scientific Process Gather Information: ○ Research, ask questions. ○ Discover what is already know about the problem ○ Has anyone already done experiments with music and houseplants? ○ If so, what did they reveal?

Scientific Process  State a hypothesis ○ A hypothesis is a suggested solution as to why something happens ○ A prediction is the expected outcome of a test, assuming the hypothesis is correct

Example of hypothesis  My hypothesis is “ classical music played to houseplants will make them grow faster and taller than houseplants with no music.”  My prediction is that “yes, this hypothesis is true.”

Test your hypothesis  To test the hypothesis we must set up carefully controlled conditions using a control group and an experimental group.  By comparing the results of the two groups; the group with music and the group without, we can see if the music does indeed affect the plant’s growth.

Control Group Test the hypothesis  A control group is a group in an experiment that receives no experimental treatment.  All conditions must be identical between the two groups except the factor we are testing for, in this case the influence of music.

Experimental Group Test the hypothesis  The experimental group is identical to the control group in every way except for the factor we are adding.  Our experimental group is the group we are playing the music to.

Independent Variable  The factor that is changed in the experiment, ( in this case, the addition of classical music) is called the independent variable.

Independent Variable  The variable that is measured in the experiment (in this case the growth rate of the houseplants) is called the dependent variable.

Make careful observations  When we perform our experiment, we must measure the results to have data to draw conclusions. To do this we must record what we observe. Observation is the act of noting or perceiving objects or events using our senses.  When you conduct an experiment you observe and record data on your dependent variable, what we are measuring.

Observation: example  In the case of our experiment with houseplants, we observe the daily changes in the amount of growth between the group with no music and the group with classical music.  This is our data. How much does each plant grow each day!  Collecting this data at regular time intervals in a “consistent controlled manner” is key to the validity of testing the hypothesis.

Organize and Analyze the Data  If we record and chart this data at regular intervals (such as daily), we can graph this data and show the difference in growth rate between the two control groups.  Organizing and analyzing the data is the next key stage after the experiment has been performed.  Putting the data in an order and comparing the data between the groups allows us to than analyze the data and to draw conclusion.

Organize and Analyze the Data  Here is an example of a graph of data showing how different brands of fertilizer affected the growth of a group of plants.  Each plant group had identical growing conditions and time; only the independent variable of the brand of fertilizer was changed!

State a Conclusion  After your data has been organized, charted and compared, it can be used to prove or disprove your hypothesis.  In the case of the two plant groups, did one group grow taller or faster than the other?  If the group with music grew faster, you have proved your hypothesis.  If not, you have disproved your hypothesis.  Your conclusion is whether or not you proved or disproved your hypothesis.

What is a Theory?  Sometimes many experiments have to be performed to prove an idea.  A theory is a set of related hypothesis that have been tested and confirmed many times by many scientists.

What is a Theory?  If several experiments were performed with many types of music and plants, and only the plants with classical music played to them grew faster, this would prove a theory that classical music only influences plant growth.  Theories involve hypothesis that must be proved many times before they are accepted by the scientific community.