The Scientific Method

Scientists use experiments to test a hypothesis or answer a question

Variables are factors or parts that can change during an experiment What is a Variable? Variables are factors or parts that can change during an experiment

Manipulated (independent) variable: what you change on purpose What is a Variable? Manipulated (independent) variable: what you change on purpose There is only ONE MV in an experiment

Responding (dependent) variable: What you are measuring. What is a Variable? Responding (dependent) variable: What you are measuring.

Controlled variables: What you keep the same (also called constants.) What is a Variable? Controlled variables: What you keep the same (also called constants.)

Parts of an Experiment QUESTION/PROBLEM What question is being answered, problem solved, or hypothesis tested. What is the purpose of doing the experiment? What is the effect of MV on RV? How does MV affect RV?

Parts of an Experiment Hypothesis An educated guess or a prediction about the results. If (the manipulated variable does this), then (the responding variable) will (describe what will happen) because (give a reason for your prediction)

Parts of an Experiment Materials: Items used during the experiment. Write in a bulleted list. Include details – how much you will need, units of measurement, sizes

Parts of an Experiment Procedures: Steps followed during experiment. Write in a numbered list Should be detailed enough that anyone can follow exactly what you did. Always say to “Record Data” Always say how many times the experiment will be repeated (4 total trials)

Parts of an Experiment Observations/Data: All the information gathered while performing the experiment. Should include written observations AND a data table

Parts of an Experiment Results/Conclusions: Analyze your data to determine the final outcome of the experiment. What do you NOW believe as a result of the experiment or observations?

Parts of an Experiment Results/Conclusions: 1. Make a Graph Decide on the kind of graph: Time progression = line, Objects = bar Set up your axis range Label your axes (x=MV, y=RV) Title your graph

Parts of an Experiment Results/Conclusions: 2. Write a conclusion paragraph Restate your hypothesis and relate your findings to it (correct or incorrect) Support your claim with at least 2 pieces of data – use numbers from your data table! Explain why/how your data supports your answer

Parts of an Experiment Share your results: Publish your findings so that others may benefit from your work.

Observations & Inferences Description of objects, events May include data from all five senses (touch/texture, smell, taste, sight, sound) Could be drawings, diagrams, written words Do not include opinions.

Observations & Inferences Drawing conclusions based on observations Often provide a reason for the event/object being observed.

Scientific Method Page (Joe & The Birthday Cake) Example Scientific Method Page (Joe & The Birthday Cake)

THeories & Laws Lay people often misinterpret the language used by scientists. And for that reason, they sometimes draw the wrong conclusions as to what the scientific terms mean. Three such terms that are often used interchangeably are "scientific law," "hypothesis," and "theory." In layman’s terms, if something is said to be “just a theory,” it usually means that it is a mere guess, or is unproved. It might even lack credibility. But in scientific terms, a theory implies that something has been proven and is generally accepted as being true.

More like a scientific law than a hypothesis. THeories More like a scientific law than a hypothesis. Explanation of a set of related observations or events based upon proven hypotheses. Verified multiple times by detached groups of researchers. One scientist cannot create a theory, he/she can only create a hypothesis. Examples: The theory of evolution, the theory of relativity, and the quantum theory.

Examples: The law of gravity, the law of thermodynamics. laws A statement of fact meant to explain, in concise terms, an action or set of actions. Generally accepted to be true and universal, and can sometimes be expressed in terms of a single mathematical equation. Scientific laws are similar to mathematical postulates. They don’t really need any complex external proofs; they are accepted at face value based upon the fact that they have always been observed to be true. Examples: The law of gravity, the law of thermodynamics.

Both are used to make predictions of events. similarities Both a scientific theory and a scientific law are accepted to be true by the scientific community as a whole. Both are used to make predictions of events. Both are used to advance technology.

A theory is much more complex and dynamic. Differences A theory is much more complex and dynamic. A law governs a single action, whereas a theory explains a whole series of related phenomena.

An analogy can be made using a slingshot and an automobile. Theories & Laws An analogy can be made using a slingshot and an automobile. A scientific law is like a slingshot. A slingshot has but one moving part--the rubber band. If you put a rock in it and draw it back, the rock will fly out at a predictable speed, depending upon the distance the band is drawn back.

Theories & Laws An automobile has many moving parts, all working in unison to perform the chore of transporting someone from one point to another point. An automobile is a complex piece of machinery. Sometimes, improvements are made to one or more component parts. A new set of spark plugs that are composed of a better alloy that can withstand heat better, for example, might replace the existing set. But the function of the automobile as a whole remains unchanged.

Theories & Laws A theory is like the automobile. Components of it can be changed or improved upon, without changing the overall truth of the theory as a whole.

Excerpted from http://wilstar.net/science/ Theories & Laws Excerpted from http://wilstar.net/science/