1. 1.1.2 The Scientific Method

2. In today’s class you should learn about..
What the scientific method is and what the main steps involved are.

3. Homework
Learn what the following mean: scientific method, hypothesis, control
In homework copy Pg 9 Q16

5. The Scientific Method
The scientific method is one method that can be used to solve a problem

6. 1.1.2 Scientific Method Observation Hypothesis Experiment Result
Conclusion
Over time as the hypothesis stands up to more and more tests it becomes accepted as a theory. A hypothesis or theory is accepted as fact only on the basis that it must stand up to challenge forever more. This is because there are limitations to the Scientific Method which means it cannot prove the truth it can only prove that ideas are false. No explanation is 100% certain e.g. better instruments, or a chance discovery, or new information or a new idea could overturn the old hypothesis. Scientists constantly challenge each others work and conclusions and scientific theory changes as knowledge increases. Scientists have to be prepared to defend their work and their explanations in public. This is done in scientific journals, at conferences and on the internet.
If hypothesis is supported
If hypothesis is not supported
Formation of
Theory and then Law
A new hypothesis needs to be found and tested

7. 1. Observation You observe something using your senses.
You may come up with a question that you would like to investigate.
machines - which are basically extensions of those senses.
Observations – all your senses.
Investigate – look at the packs, reseach how mouthwashes work.

8. The scientist tries to explain what caused what was observed.
2. Hypothesis: 
The hypothesis is an explanation for what a scientist observes. It has to be testable. .

9. 3. Experiment
You design a fair experiment to test whether your hypothesis is correct or not.
You must use a control experiment
The outcome must be measurable.
You must do replicate experiments ( exact copies of an experiment) .

10. Principles of experimentation
This is not a fair test because…

11. Control Group -no mouthwash
Testing which mouthwash
is better at killing
bacteria on the plates.
What could the control be?
Control Group -no mouthwash
Petri dish
Bacteria grown from swab
Listerine
Experimental Group
Wal-Mart brand

12. Definition :
A control experiment is a standard experiment used for comparison

13. 4. Result
Record and analyze data (information gathered from an experiment).

14. 5. Conclusion You state whether your hypothesis was correct or not
Try to explain your results.

15. Finally
1. You Report and Publish your results. in a Journal
2. If a hypothesis is supported by many experiments it becomes known as a theory.
3. When a theory is supported over a long period of time then it becomes known as a Law or Principle.

16. 1.1.2 Scientific Method If hypothesis is supported
If hypothesis is not supported

17. Limitations of the Scientific Method

18. Today we will … Learn about How drug trial experiments work
What the limits of the scientific method are

19. Limitations of the Scientific Method
Is limited by what can be observed with our five senses.
The basis of the investigation (bad design)
limitations of our measurement instruments
may be affected by time pressure for results
e.g., what existed prior to the Big Bang and the known universe is outside of the realm of science to investigate. We cant investigate it because it was outside our time
e.g., temperature

20. Limitations of the scientific method
scientists sometimes make mistakes
Interpretation of results may be affected by the emotional involvement of investigator
Some problems are solved by serendipity!

21. Check your learning.. What is the scientific method?
What are the main steps?
Define Hypothesis
What should be involved in a good experiment?
Define control?
What happens after a hypothesis is verified?
Distinguish between a theory and a law
Explain 3 limitations of the scientific method

22. Drug testing terms As with every experiment its important to
Use a LARGE SAMPLE SIZE
And use RANDOM SELECTION
Placebo - Control used in drug testing
Single blind test
Either the Scientist or the test subject knows which is the real pill and which is the placebo
Double blind
Neither the tester nor the person being tested knows which is the real pill and which is the placebo.

23. Can you…
Explain some of the limits of the scientific method to solve problems?
Tell why the following are important
Large sample size, random selection, placebos, single blind testing, double blind testing