Welcome! Please get out your Scientific Method Review sheet and read the board. Eaarth tips: Post paper before the rush! Make sure you’ve answered all the questions! FB group Your own work When you put cut flowers in water, adding a teaspoonful of sugar to the water will make the flowers last longer. Why is it important that there is more than one group in this study? Why is it important that there is only ONE thing that is different between the two groups? Why is it important that all other things be the same between the two groups? Could you have more than two groups? What might they look like? A number of studies indicate that if people eat a diet that is low in fat, then their chance of getting colon cancer will be decreased. What is the ONE thing that is different between the two groups? What other factors/conditions/characteristics must be the SAME between the groups? What will be measured/counted at the end? What might be an appropriate hypothesis for this study? The mercury preservative used in some childhood vaccines can cause autism-like symptoms in newborn mice, but only in those with a particular genetic susceptibility, according to a Columbia University study. What is the ONE thing that is different between the two groups? What other factors/conditions/characteristics must be the SAME between the groups? What will be measured/counted at the end? What might be an appropriate hypothesis for this study? Doctors at the Latter-Day Saints Hospital in Salt Lake City, Utah, have determined that patients that receive antibiotics more than two hours before or two hours after surgery are six times more likely to develop an infection than those patients that receive antibiotics within a two hour window before or after surgery. What is the ONE thing that is different between the two groups? What other factors/conditions/characteristics must be the SAME between the groups? What will be measured/counted at the end? What might be an appropriate hypothesis for this study? Now you try it! Reteach Definitions of control group and controlled variables – how are they different? If a variable is the independent variable, can it also be a controlled variable? How does using the words If/then in a hypothesis help you identify the independent vs. dependent variable? “Controlled variables” refers to components that are the same BETWEEN control and experimental groups Beyond the science fair Methods of scientific study Learning objective: To define the methods of scientific study that you’ll encounter this year and then to compare their advantages and disadvantages. To practice effective note taking Lab Studies: Appropriate uses When all variables can be controlled When set up can provide information that reflects real world When many trials are needed (hundreds/thousands?) Example: Testing to see if sunflowers can be used to remove lead from contaminated soil. Animal Studies: Appropriate uses Before a substance is tested on humans When all variables can be controlled (clones can be used to control genetic differences!) When set up can provide information that reflects real world When many trials are needed (hundreds/thousands?) Example: Testing a new HIV treatment or testing a consumer product like eye makeup Epidemiological Studies: Appropriate uses Compares groups of people May be blind or double blind May follow people for decades Surveys identify appropriate study subjects Example: Do Japanese people who eat traditional diets have less heart disease than those who have adopted a Western diet? Case Studies: Appropriate uses Provides information about humans (not animals) Compares groups of people as epidemiological studies Case data is gathered from doctors and hospitals by the researcher Usually for something that rarely occurs Example: Studying the effects of lead on the children of Galveston Field research: Appropriate uses Events or subjects studied in natural setting. Often compares two areas: one with the IV, one which lacks the IV (for control) RULE!!!!: Do no harm! Example: Study the effects of fire on native seed germination rates. Check for understanding: Which type would you use? What is the effect of different plowing methods on soil nutrient loss? Do the elevated levels of Ritalin in our drinking water cause health problems? What are the best conditions for biodegradable plastic to break down? Now let’s compare the types Lab studies vs. Field – what are the advantages and disadvantages? Case studies – How is this limited? Epidemiological studies vs. Animal testing – advantages/disadvantages? Write in at least one advantage and disadvantage for each type.