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Introduction to science and sci method
1. Observation vs. Inference
Observation - observed using the senses
Quantitative -measurable
3 meters
35 degrees Celsius
4 paper clips
Qualitative - not measurable; describable
red flowers
dark blue
bitter taste
Inference - a conclusion based on observations
7. The Scientific Method
DESIGN
Purpose - Question
Research - Information
Hypothesis – Suggested Explanation (Testable)
Variables - Independent, Dependent, Controlled
Experiment - Test
DATA COLLECTION AND PROCESSING
Collect Data - Raw Data
Analysis – Results, Data, Graphs, Charts
CONCLUDE AND EVALUATE
Conclusion - Support/Refute hypothesis***
Evaluate - Lab for error and limitations
8. Hypothesis
A statement (predicition) or "educated guess" that can be tested
If skin cancer is related to ultraviolet light , then people with a high exposure to uv light will have a
higher frequency of skin cancer.
Follow If, then statement
10. Hypothesis
Question: Does water affect plant growth?
If plant growth is related to water, then plants that receive more water will
grow faster/grow taller
Plants that receive more water will grow faster/will grow taller
11. Variables in a Controlled Experiment
Independent Variable = Controlled or manipulated by the experimenter
Dependent Variable = Changes in response to the IV (depends on IV)
Controlled Variables - must stay the same
0 10 15 20
One Independent Variable
Everything else is controlled
12. If skin cancer is related to ultraviolet light , then people with a high exposure to uv light
will have a higher frequency of skin cancer.
Problems???
15. The Strange Case of BeriBeri
In 1887 a strange nerve disease attacked the people in the Dutch East Indies. The disease was beriberi.
Symptoms of the disease included weakness and loss of appetite, victims often died of heart failure.
Scientists thought the disease might be caused by bacteria. They injected chickens with bacteria from the
blood of patients with beriberi. The injected chickens became sick. However, so did a group of chickens that
were not injected with bacteria.
One of the scientists, Dr. Eijkman, noticed something. Before the experiment, all the chickens had eaten
whole-grain rice, but during the experiment, the chickens were fed polished rice. Dr. Eijkman researched
this interesting case and found that polished rice lacked thiamine, a vitamin necessary for good health.
1. State the question.
2. What was the hypothesis?
3. How was the hypothesis tested?
4. Should the hypothesis be supported or rejected based on the experiment?
5. What should be the new hypothesis and how would you test it?
16. How Penicillin Was Discovered
In 1928, Sir Alexander Fleming was studying Staphylococcus bacteria growing in culture
dishes. He noticed that a mold called Penicillium was also growing in some of the
dishes. A clear area existed around the mold because all the bacteria that had grown in
this area had died. In the culture dishes without the mold, no clear areas were present.
Fleming hypothesized that the mold must be producing a chemical that killed the
bacteria. He decided to isolate this substance and test it to see if it would kill bacteria.
Fleming transferred the mold to a nutrient broth solution. This solution contained all the
materials the mold needed to grow. After the mold grew, he removed it from the nutrient
broth. Fleming then added the nutrient broth in which the mold had grown to a culture of
bacteria. He observed that the bacteria died which was later used to develop antibiotics
used to treat a variety of diseases.
6. Identify the problem.
7. What was Fleming's hypothesis?
8. How was the hypothesis tested?
9. Should the hypothesis be supported or rejected based on the experiment?
10. This experiment lead to the development of what major medical advancement?
