The Scientific Method

What Is The Scientific Method? Organized series of steps Used to solve problems 6 main steps! (sometimes 5 steps, depending on who you are) Scientists use many approaches to solve a problem, but all use these MAIN steps at some point!

Why Do We Need A Method? To stay organized and not repeat mistakes So that other scientists can replicate the experiment with similar results To add to your amount of evidence Help prevent speculation

The Big Problemo… STEP 1 !! Identify a question you want to answer! What do you want to figure out…

Research… Step 2 !! Gather any and all information on your problem’s topic! Use the internet, library, journals, specialists, etc… just make sure it is valid evidence!!

Hypothesis… (Not Hypotenuse!!) Step 3 !! Form an educated guess that provides a possible answer to the problem statement. “If…then…” format should always be used!

Examples… If cat food is fed to a dog twice a day, then it will turn into a cat in one week. If one teaspoon of salt is added to a goldfish bowl weekly, then in ten weeks the fish will be able to survive in the Atlantic Ocean.

Experiment… (The Fun Part!) Step 4 !! Perform the actual procedures used to support or reject a hypothesis. Can have several parts to it. Can use many different materials and pieces of equipment.

Data…Lots of Data… Step 5 !! Collect and record information and results from the experiment. Graphs & tables used commonly –Pie, bar, & line graphs

Conclusion… Step 6 !! Written response using the results of the experiment. Supports or rejects the hypothesis.

What If I Was Wrong?? It’s ok to be wrong! Try again! Tweak factors in your experiment! No experiment is a bad experiment!! YOU CAN LEARN FROM EVERYTHING!

Independent (Manipulated) Variable The item being tested or changed… There should be only 1 independent variable!

Dependent (Responding) Variable Change that occurs due to the procedures performed on the independent variable. Independent Controls Dependent!!

Control… Must be present to make an experiment valid!! Used for a comparison! Part not tested, it is original, not altered! CONTROL

Theory… A well-supported hypothesis that unifies a broad range of observations Enables scientists to accurately predict what will happen in new situations

Law… Concise statement that expresses a fundamental principle of science Differs from theory because it doesn’t speculate; it’s just the results of repeated observations

Most scientific data is presented as a graph!!!

Line Graph Bar Graph Pie Graph

These are graphs with rectangular bars, with different lengths, that are proportional to the value they represent. Bar charts are used for comparing two or more values.

These are circular charts, divided into sections, that illustrate the relative magnitudes, percents, or frequencies. Together, the sections create a full disk (360 degrees)

Line graphs are the most useful type of graph for representing and interpreting data –This type of graph shows how one variable is changed by another

DRY MIX!!Which variable goes where???? DRY MIX!! –Dr y –Dependent (responding) variable – The variable that depends on the independent variable. This goes on the y- axis!! –Im x –Independent (manipulated) variable – The variable we are manipulating. This goes on the x-axis!!!

Title – Should be in the form of, “The dependence of [dependent variable] on [independent variable]” Y axis label, be sure to indicate units of measurement X axis label, be sure to indicate units of measurement * Make sure that your scale on both the x and y axes are consistent and reasonable

The data in the graph should fill the page Use a ruler!!!! Graphs should always be shown as smooth lines or curves (aka TRENDLINE) Never connect the dots with straight lines to form a saw-tooth pattern

Smooth lines???? Why? –The data we take is not perfect. We are looking for overall trends, not individual data points!!!!! What do abrupt changes in a graph tell you? –Obvious discontinuities suggest a significant change has taken place. If possible this measurement needs to be repeated!

In a direct relationship, as one variable increase/decreases, the other variable also increases/decreases Direct relationships graph as a straight line

In an inverse relationship, as one variable increases, the other decreases Inverse relationships graph as hyperbolas