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 groupYour 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 controlledWhen set up can provide information that

reflects real worldWhen 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 humansWhen all variables can be controlled (clones can

be used to control genetic differences!)When set up can provide information that

reflects real worldWhen 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 peopleMay be blind or double blindMay follow people for decadesSurveys identify appropriate study

subjectsExample: 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 occursExample: 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.