What is Science? The pics are used for education purposes only

Transcription

1 What is Science? Science is one of many ways to investigate and understand the world around us. It is a search for knowledge through observation, description, identification, and experimental investigation.

2 What is Science? The method of approach is systematical and methodological.

3 Types of Science Earth Science study of Earth Geology, Meteorology, etc.

4 Types of Science Biological Sciences study of living things Botany, Zoology, Ecology, etc.

5 Types of Science Physical Sciences study of matter and energy Physics, Chemistry, etc.

6 The Scientific Method

7 The Scientific Method- Observation We human beings are designed to be curious creatures. We always ask the question, Why? How does it work? For example, in 1897, an English physician named Ronald Ross noticed that patients in the field hospital who did not have malaria were more likely to develop the disease in open wards.

8 Observation Observations suggest questions to investigate.

9 The Scientific Method- Hypothesis A hypothesis is an educated guess which is testable and can explain an observation. It is the basis of further investigation. Dr. Ross suggested it is perhaps the mosquitoes in the open wards that might have spread the disease from patients with malaria to patients who did not have the disease.

10 Hypothesis We predict what may or may not happen through the hypothesis.

11 Guess who this is? Hypothesizing why the apple hit his head!

12 Scientific Method- Prediction Prediction is the framework for testing hypothesis; it is what we expect to happen if our hypothesis is accurate. Our prediction can either be supported or rejected through a controlled test of a hypothesis called an experiment. Dr. Ross predicted that if the mosquitoes were spreading malaria, then mosquitoes that had bitten malaria patients and sucked up some of their blood would have picked up the parasite.

13 How do we test our hypothesis? We do an experiment!

14 Scientific Method- Experiment The controlled test of a hypothesis is called an experiment. Within an experiment, there is a control group and an experimental group. The experimental group is exposed to the variable suspected of causing an effect. The control group is not exposed to the variable and serves as the standard for comparison.

15 Is this a controlled experiment?

16 Controlled experiment In a scientific research experiment, there are factors called variables. The independent variable (IV) is the factor that we manipulate (we control and change). The dependent variable (DV) changes in response to the IV.

17 Dr. Ross s experiment Since the variable in Ross s experiment was exposure to malaria parasites from the blood of malaria victims, he compared mosquitoes that had fed on malaria patients with those that had fed on uninfected individuals.

18 What was the experimental group? Ross first looked for malaria parasites in mosquitoes that had fed on the blood of malaria patients. He dissected each mosquito s stomach and found the live parasite.

19 What was the control group? Ross used mosquitoes that had not bitten someone with malaria. He checked to see if these mosquitoes contained parasites. If BOTH groups had parasites in their stomachs, then mosquitoes could not be the carrier. Ross also allowed a group of newly born mosquitoes to feed on people who did not have malaria. Once again, he examined the stomach contents and found no parasites.

20 Scientific Method-Theories After statistical analysis, we can either support our original prediction (hypothesis) or reject it. If the hypothesis is supported with statistics, we can reject the null hypothesis. The null hypothesis says that the differences between the experimental and control group is due to random chance.

21 Scientific theory If the null hypothesis is not rejected, then our prediction is not supported. We must then revise our original prediction and conduct another research experiment. If the null hypothesis is rejected, our prediction is then supported. However, further testing must be done to demonstrate consistency in the findings.

22 Scientific theory The results are to be interpreted and a theory is formed. If we support our hypothesis, many more experiments are needed to verify our findings. Over time, our hypothesis may be formed into a theory. A theory is a unifying explanation for a broad range of observations.

23 Ross s theory Theories can have a major effect on science when they tie many accepted hypothesis together into a unified concept. The idea that malaria epidemics could be prevented by combating mosquitoes was first put forth a letter written by Ross to the government of India in Before the end of that year, American army doctors had eliminated almost all malaria from the epidemic-prone Cuba by reducing the mosquito population.

24 Theory Is evolution even a theory?

25 Scientific Method-law When theories are supported over the course of time, a law is formed. A law is a possible explanation of a naturalistic occurrence. It is basically a scientific fact.

26 Law Ex: The law of gravity; law of thermodynamics; law of conservation of energy.

27 Review of scientific method Recent studies in many alcohol journals have shown the problem of binge drinking in college campuses. They have demonstrated that such drinking is usually associated with social events. However, is there a biological basis to the cause of binge drinking? In addition, are there any physiological problems caused by such drinking behaviors?

28 Hypothesis? Perhaps it is due to the positively reinforced social behaviors related to alcohol. Commercials, parties, coolness

29 Hypothesis? Perhaps it is due to the addictive powers of alcohol. It is a mind altering drug that people abuse.

30 Hypothesis? Perhaps the religious people are right and we are just messed up people for sin!

31 How do we test this? Four groups (n=200) of young rats individually caged weighing about 300 gram will be tested. Experimental groups Trained to consume alcohol in the presence of food Trained to consume alcohol in the presence of another rat

32 How do we test this? Control groups Trained to consume water in the presence of food Trained to consume water in the presence of another rat

33 What is the procedure? Each group of rats will be put into a Pavlovian box that will run the autoshaping procedure program. The sessions will run for about 30 minutes each, once in the morning and once in the afternoon. Over the course of time, the concentration of alcohol will be increased by 1% increment.

34 What will we use to support our hypothesis? Measure the amount of alcohol consumed within the rats after each session. Measure the blood alcohol and corticosterone levels at the final session. Assess the liver and brain. Observe and record animal behaviors during alcoholic and nonalcoholic sessions.

35 Prediction? Rats in the alcoholic groups will consume more fluids than rats in the water groups. Rats in the alcoholic groups will have high blood alcohol and corticosterone levels compared to those in the water groups. Rats in the alcoholic groups will have internal biological problems associated with their livers and brains. Rats in the alcoholic groups will have behavioral problems associated with the consumption of alcohol.

36 Results? The entire experiment supported our hypothesis and predictions. Rats in the alcoholic groups consumed more fluids, have high blood alcohol content, liver and brain problems, and were stressful. Interestingly, the social interaction group consumed more alcohol than the food group.

37 Discussion/Conclusion Don t drink! At least, don t binge drink! In 20 minutes, these rats exposed to alcohol consumed enough to be 3 to 4 times over the N.J. state legal limit. Rats are like humans in that they are social creatures. They prefer to spend time with another rat rather than consuming food. The rats seemed very stressed when they were left in their cages without alcohol. It is only when they are back in the Pavlovian boxes that they seem happy.

38 Discussion/Conclusion Alcohol has a positive feedback loop. In other words, the more one drinks it, the more he wants. Genetically inclined to addiction? In a separate study, a group of rats that have been exposed to the Pavlovian conditioning procedures were not given alcohol anymore after 3 months of training.

39 Addiction in genes? After 3 weeks in their cage without consumption of alcohol, these rats were put back into the Pavlov boxes. They went back to their old self again as they consumed even MORE alcohol. Implication? The extinction procedure did not work. The rats did not forget how to sin. Was this addiction?

40 In summary Scientific progress is made by posing hypothesis and testing their predictions. Verification of hypothesis is required before they are widely accepted. Control experiments are important in testing hypothesis. Control groups are used for comparison with experimental groups.

41 More summary A theory links well-supported hypothesis together in one concept. All scientific theories can be overturned by new evidence. Scientific laws are basically facts within the scientific community. However, like theories, they can be overturned by new evidence as well.

42 Scientific paper In any scientific papers, there is an Introduction, which gives the background; the Materials & Method, which gives the procedure; the Results, which shows only statistical analysis; and a Discussion, which talks about why the author thinks certain things happened. The conclusion is also written in this section.

43 Chewing gum experiment Intro: Wrigley claims that chewing gum helps improve concentration. Driving question: Does chewing gum actually help improve memory?

44 Chewing gum experiment Hypothesis: Chewing gum does help improve memory. Materials & Methods: Procedure includes a a group of people not chewing gum versus another group not chewing gum while taking a concentration test

45 Flawed testing? Placebo effect: measurable improvement of health not attributed to treatment Random sampling: the testing must reflect the sample of the population Double blind procedure: test of internal validity in which neither the researcher nor the subject knows which group is the experimental group Standard variable: Could test the effects of gum chewing over time

46 Did gum chewing really help? Differences in test score may be due to random chance (unless shown differently statistically) Perhaps the sugar increased concentration How valid was the controlled testing? Was it set out to measure what was supposed to be measured?

47 Did gum chewing really help? How reliable was the test? Perhaps another set of memory test would yield more accurate results. Some of the subjects being tested may know a lot of vocabulary terms already (once again, random sampling is needed).

48 What is the difference between Causation and Correlation? In a controlled experiment involving one IV, the implication is that particular IV caused the effect. Correlation studies suggest that the IV has a positive or negative relation with the DV. However, one cannot conclude that the IV caused the DV, just somehow related. Correlation suggest trends!

49 Causation or correlation?

50 Causation or correlation?

51 Why study the scientific method? Helps us understand where scientific knowledge comes from Allows us to analyze the strengths and weaknesses of the scientific model Teaches us a new way of viewing and appreciating the world around us

52 Key terms Hypothesis, prediction, theory, law, scientific method Controlled experiment, independent variable, dependent variable, control group Null hypothesis, placebo effect, random sampling, double blind procedure, validity, reliability