The Scientific Method

What is the Scientific Method? A set of steps or procedures that you follow when conducting an experiment.

OBSERVATION & Asking a Question Use the 5 senses to record what you observe. Then turn your observations into a question.

HYPOTHESIS A proposed scientific explanation. This statement is testable and can be confirmed with experimentation or further observation.

PREDICTION Forecast what will happen in an experiment if the hypothesis is true Written in an if-then statement

Which box represents observations? B In 1976 an outbreak in South Africa started with individuals suffering from severe headaches, fevers, bloody diarrhea, and vomiting. Eventually they suffered from internal bleeding with blood leaking from the nose, ears, and skin. Finally death came from collapse of the cardiovascular system due to lack of blood. A What causes the victims to die? How is it transmitted? What might differ between these investigations? D The virus is isolated from a victim causes the hemorrhagic fever. C If the virus were the causing agent, then introduction of the virus into healthy tissue would cause cell death.

Which box represents observations? Observation (B) In 1976 an outbreak in South Africa started with individuals suffering from severe headaches, fevers, bloody diarrhea, and vomiting. Eventually they suffered from internal bleeding with blood leaking from the nose, ears, and skin. Finally death came from collapse of the cardiovascular system due to lack of blood.

Which box represents questions? A What causes the victims to die? How is it transmitted? What might differ between these investigations? D The virus is isolated from a victim causes the hemorrhagic fever. C If the virus were the causing agent, then introduction of the virus into healthy tissue would cause cell death.

Which box represents observations? Observation (B) In 1976 an outbreak in South Africa started with individuals suffering from severe headaches, fevers, bloody diarrhea, and vomiting. Eventually they suffered from internal bleeding with blood leaking from the nose, ears, and skin. Finally death came from collapse of the cardiovascular system due to lack of blood. Questions (A) What causes the victims to die? How is it transmitted? What might differ between these investigations?

Which box represents a Hypothesis? D The virus is isolated from a victim causing the hemorrhagic fever. C If the virus were the causing agent, then introduction of the virus into healthy tissue would cause cell death.

Which box represents observations? Observation (B) In 1976 an outbreak in South Africa started with individuals suffering from severe headaches, fevers, bloody diarrhea, and vomiting. Eventually they suffered from internal bleeding with blood leaking from the nose, ears, and skin. Finally death came from collapse of the cardiovascular system due to lack of blood. Questions (A) What causes the victims to die? How is it transmitted? What might differ between these investigations? Hypothesis (D) The virus is isolated from a victim causes the hemorrhagic fever. Prediction (C) If the virus were the causing agent, then introduction of the virus into healthy tissue would cause cell death.

MINI LAB: CAN SCIENTIFIC METHODS BE USED TO SOLVE A PROBLEM?

EXPERIMENT Test the hypothesis and prediction

EXPERIMENT A. Controlled experiment: has a control group and an experimental group differing by only one factor (variable). Constants: Variables that remain the same between the experimental and control groups. –Ex. When testing the effects of fertilizer on fruit production, everything would stay the same between two groups of plants (water, sunlight exposure, amount of fertilizer etc). They only difference is the type of fertilizer.  This way any difference seen between the two plants would have to be due to the fertilizer.

EXPERIMENT B. Independent vs Dependent Variable Independent (cause): variable scientists change or manipulate Dependent (effect): changes as independent changes. The variable you are measuring. Ex: Scientists control fertilizer type given to plant (independent variable), but have no control over how many fruits the plant produces (dependent).

EXPERIMENT C. Collecting data (information scientist gather) Observations and measuring Sampling (using a small part to represent a bigger part) must be large and random Quantitative (numerical and objective) vs qualitative (observed or descriptive and subjective) data. Ex. Fruit color would be qualitative data whereas the number of fruits produced would be quantitative data.

DATA ANALYSIS – Organize data (tables, graphs, etc.) –Run statistics and model data –Accept or reject hypothesis

Draw or form CONCLUSION –Explain data, results, hypothesis –Make inferences –Summarize experiment and form new questions

COMMUNICATE Share your findings with other scientists. TalkInternet Write