the scientific method. what is the scientific method? a series of steps used to answer questions...
TRANSCRIPT
Unit 1: Intro to Earth/Environmental Science
The Scientific
Method
What is the Scientific Method?
A series of steps used to answer questions about the world around us…
Steps…1. Problem/Ask a questionGather Information
2. Hypothesis3. Experiment4. Data5. Results6. Conclusion7. Repeat
1. State the Problem
o Based on observations
o MUST be scientific, NOT an opinion
After 65 million years, no fossil evidence of dinosaurs.
oQuestion: Why did dinosaurs go extinct?
Gather information
o Some information is needed before the process can begin. Either the scientist already has some needed information or background research needs to be done.
o Collect data
o Take measurements
Evidence: Iridium layer, crater, shocked quartz, and tsunami
Crater
Chicxulub Crater
Shocked Quartz
2. Form a Hypothesis
oPossible explanation that is based on facts (educated guess!)
oMUST be an IF…THEN statement
If shocked quartz and an Iridium layer were found then a meteor striking the Earth must have killed the dinosaurs 65 million years ago by producing a cloud of dust around the earth lowering temperatures.
o Could have also been an asteroid or comet.
3. Conduct your ExperimentoTest your hypothesis
Luis (left) and Walter Alvarez at the K-T Boundary in Gubbio, Italy 1981 looking for evidence of an iridium layer.
Pieces of an Experiment…
o Control: a standard to which all the other results can be compared (Before 65 mya, dinosaurs and mammals co-exsited)
oConstant: a factor that does not change when other factors do (mammals are found before and after 65 mya in the fossil record)
Independent vs.Dependent Variables
The Cretaceous–Paleogene (K–Pg) extinction event,formerly known as the Cretaceous–Tertiary (K–T) extinction
o Independent: The variable that is changed by US, the scientist. (looking for evidence of iridiumin the rock record around the globe)
o Dependent: The variable that
responds to the change in the
independent variable. (Finding
a layer of iridium, a rare element in earth’s rock
160 times normal around the
globe).
4. Record Your Data
o Gathered evidence recorded during your experiment
Types of Data…
oQuantitativeon* = NUMBERSo7 days or 3 feet
oQualitativeo l* = LETTERSoGreener or taller
Chicxulub crater is locatedunder 3,600 feet of sediment
The clay around the cratercontains an abundance of iridium
o Dust and debris would have covered the earth causing it to cool rapidly. Plants would die from lack of sunlight; animals would die from lack of food.
o 3/4 of all species on earth disappeared.
5. Results
Summary of the data
Can be graphs, charts or sentences
6. Draw Conclusions
oWhat did you learn from doing the experiment?
7. Revise and Retest
oAccept or reject your original hypothesis
oWhy repeat?
Accept hypothesis!!o Became known
as the meteorite impact theory or the K-T Extinction
http://www.youtube.com/watch?v=Dcp0JhwNgmE
Theory vs. Lawo Theory: can be tested
o Ex. Theory of Plate Tectonics
o Law: Proven fact of natureo Ex. Gravity
List the steps of the scientific method and explain why it is important to scientists.
Sept. 4, 2013
Bart believes that mice exposed to microwaves will become extra strong. He decides to perform this experiment by placing 10 mice in a microwave for 10 seconds. He compared these 10 mice to another 10 mice that had not been exposed. His test consisted of a heavy block of wood that blocked the mouse food. He found that 8 out of 10 of the microwaved mice were able to push the block away. 7 out of 10 of the non-microwaved mice were able to do the same.
Bart and Microwave
What is the control group?A. Mice in the microwaveB. Mice not exposed to microwave
What is the independent variable?A. Exposure to microwaveB. Strength of the mice
A soccer team is holding a car wash to raise money. They are charging a flat rate of $10.00 for each car that gets washed.In this situation, the amount of money raised (revenue) is dependent on the number of cars washed. Therefore, the amount of money raised (revenue) is the dependent variable, and the number of cars washed is the independent variable.