the scientific method. question well defined testable measurable controllable reasonable and...
TRANSCRIPT
Question
• Well defined
• Testable
• Measurable
• Controllable
• Reasonable and consistent with existing bodies of knowledge
Consider These Questions
• Are serial killers evil by nature?
• What is the cause of AIDS?
• Why is grass green?
• What is the best recipe for chocolate chip cookies?
• When will the big earth quake hit San Francisco?
Which of the following is a useful scientific hypothesis?
• Plants absorb water through their leaves as well as their roots.
• Mice require calcium for developing strong bones.
• Dogs are happy when you feed them steak.
• HIV can be transmitted by cat fleas.
Variables
• Dependent• The variable measured, counted, or recorded.
• Placed on y-axis of a graph
• Independent• What the investigator deliberately varies or manipulates during an experiment.
• Chosen because it is thought to affect the dependent variable
• Placed on x-axis of graph
• Control• Variables or factors that are kept equal in all treatments.
Identify the D and I variables
• Height of a bean plant recorded daily for 2 weeks.
• Mice are kept at different temperatures for 6 weeks. Percent weight gain is recorded.
• A hypothesis proposes that dog weight increases with fewer litter mates.
• Seeds are soaked in salt solutions of different concentrations and germination is counted each day.
• The diversity of coastal algal species is calculated before and after an oil spill.