Homework:Scientific Method in the Real World  Find an article or video from a reputable scientific source that demonstrates the application of the scientific method.  Must be related to some field of Biology

Scientific inquiry Experimental Design

In- Scientific Method  Read the last page of the black box packet.  Write each hypothesis and determine which would be useful for a scientific investigation.  Explain each answer.  Create a general statement about the characteristics of a useful hypothesis

Thru-Scientific Inquiry

Question  Based on observations or information gained from previous research.  If an experiment can be done or data can be collected, then a question can be answered scientifically

Hypothesis  Potential answer to the question  Can be in If, Then format or just a statement  Only useful if it can be falsified through experimentation

Variables  Independent Variable-deliberately varied during the experiment. Affects the dependant variable.  Can often be time.  May not be directly manipulated by the investigator, but data can be collected to evaluate the hypothesis.  Ex: Are more crimes committed during a full moon?

Variables  Dependant Variable- what is measured during the experiment  Indicates the effect of the independent variable

Identify the Variables  The diversity of algal species is calculated for a coastal area before and after an oil spill  Guinea pigs are kept at different temperatures for six weeks. Percent weight gain is recorded.  A scientist hypothesizes that the adult weight of a dog is higher when it has fewer litter mates (brothers and sisters) as a puppy.

Controlled (standardized) Variables  Factors that are kept the same in all treatments  Isolates the effect of the independent variable on the dependant variable.

Controlled Variables  A scientist wants to determine the effect of temperature on the amount of chicken eggs hatched  What is the IV?  DV?  Controlled Variables?

Levels of Treatment  The values set for the independent variable  Treatment levels are varied to obtain a broad set of data  Typically based on prior knowledge of the system.

Control Group  A treatment in which the independent variable is either eliminated or is set at a standard value (room temperature, etc.)  Results are compared to experimental treatments

Identify the control group  A scientist studies the amount of alcohol produced by yeast when it is incubated with different types of sugars  The effect of NutraSweet on tumor development in lab rats is investigated  The effect of light intensity on photosynthesis is measured by collecting oxygen produced by a plant.

Replications (trials)  Repeat the experiment several times using the exact same conditions.  Determines consistent results  Don’t expect the exact same result in each replication. A certain amount of variation is expected in biological systems.  Be sure your sample size is not too small

Out- Experimental Design  A group of students hypothesizes that the amount of alcohol produced in fermentation depends on the amount of glucose supplied to the yeast. They want to use 5%, 10%, 15%, 20%, 25%, and 30% glucose solutions. 