SCIENTIFIC METHOD NOTES # 1

Table of Contents Lecture/Lab/Activity Date Pg# 1.Scientific Organization 8/24/ Scientific Method 8/25/10 1 Objective: Using the Scientific Method, the student will work in lab groups to perform the “Come Fly With Us” lab and document their analysis in a lab write up. Agenda: Scientific Method – Lecture Come Fly With Us – Lab Activity

A series of logical steps to follow to solve problems Define the Scientific Method:

You cannot solve a problem until you know exactly what it is. Look at the world around you to make observations. What senses do we use to observe the world? –Sight –Sound –Smell –Touch –Taste Step 1: State the problem

Types of Observations When you make observations there are two types : –Quantitative – observations based on numeric value (the grass is 5 cm tall) –Qualitative – observations based on descriptive terms ( the grass is green)

What will it take to solve my problem? What do I know, and need to know, about my problem? - Examine the possibilities. - Eliminate poor choices. - Consider likely choices. Step 2: Research the problem

Step 3: Form a hypothesis A possible solution to my problem. The simplest solution is often the best solution! The _____________ causes the speed of the reaction to __________.

VARIABLES: Variable - The factor being tested in an experiment. Independent (manipulated) – factor adjusted by the experimenter Dependent (responding) – factor whose value depends upon the value of the independent variable

Perform an experiment to see if your hypothesis works. How would you test your hypothesis? Step 4: Test the hypothesis

Controlled Experiment:. Control - A part of the experiment without the variable. This part of the experiment is used as a comparison. Data - Observations from the experiment. Constant – factor that does not change or vary in an experiment

Data are the results of an experiment. In its simplest form, there are only two possibilities: –(1) If your hypothesis was correct, PROBLEM SOLVED! –(2) If your hypothesis was incorrect, the experiment failed. DON'T GIVE UP! DO MORE RESEARCH! - What was wrong with your original hypothesis? - Did you make a poor selection? - Was your experiment flawed? Step 5: Draw conclusions from the data

Continue this process until the problem is solved! If the hypothesis is proven to be incorrect, you must find out what was wrong with it. This might lead to the formation of a hypothesis about the hypothesis!

Scientific Theory A logical explanation of observed events, based on repeated experimentation.

Scientific LAW Sums up related observations and experimental results to describe a pattern in nature.

Accepted Value – based on reliable references Experimental Value – measured in the lab –Error = experimental – accepted Positive value – accepted value is greater than he experimental value Negative value – accepted value is less than the experimental value % error = | value accepted – value experimental | x 100% Value accepted

Example: –A student measures the mass and volume of a substance and calculates its density as 1.40g/mL. The accepted value of the density is 1.36g/mL. What is the percent error? %error = | 1.36g/mL –1.40g/mL| 1.36g/mL x 100 = 2.9 %