Scientific Method

What is Scientific Method? Scientific method is the process used to answer questions and solve problems about the world around us.

There are 6 steps to scientific method these steps are followed to test ideas, but serve only as a guide. Sometimes, several of the steps are used while others are not needed when solving a particular problem. Or, the steps might be performed in a different order.

Step #1 You recognize a problem and ask a question. Decide what you want to know **Write this

Step #2 Gather information –Previous knowledge –Make observations –Do research **Write this

Observation vs. Inference Observation is what you notice * Ex. The dog is barking Inference draws a conclusion or makes an explanation * Ex. The dog is hungry An inference is usually based on previous knowledge. **Write this

Observation Observation: when studying something, describe only facts that you can see, touch, smell and hear. You are not making any guesses. THIS IS NOT AN OPINION!! Ohh… This liquid is green and it is leaking from a brown can. I also smell it.

Inference Inference: using your observations to make a guess about an object or an outcome THIS CAN BE A SCIENTIFIC OPINION Based on my observations, I think that this can is old and is leaking a toxic substance.

Group Practice Please make some observations and inferences about the following picture.

Individual Practice On your note packet, please write down 2 observations and 2 inferences about the following picture.

Step #3 Form a Hypothesis A hypothesis is a prediction that can be tested. It is often written as “If” “then” statements “If I do this (independent variable ) then (dependent variable) will happen” **Write this

Step #4 Testing your hypothesis Testing your hypothesis involves an observational study OR an experiment. **Write this

Observational Study Does not involve an experiment. You observe without changing the variables. The scientist observes and record his/her observations.

An Experiment An experiment has a control, variables, and a constant.

Controls and Variables A control is a standard with which to compare the results of your experiment.** Variables are factors in an experiment.** **Write this

Types of Variables Independent Variable is the variable you purposely change. This is what is being tested. ** Dependent Variable is the variable that changes in response to that change. It is the factor that is observed and measured.** **Write this

Controlled Variable or Constant A constant is all of the other variables in the experiment that should not change…they always stay the same.** **Write this

Which soda, when combined with mentos, explodes the highest? Independent variable: What are we testing? Type of soda Dependent variable: What will we measure? Height of explosion Controlled variables/Constants: What will stay the same in all tests? Number of mentos, type of mentos, amount of soda

Step #5 Analyze your data** * Data is the information collected in the experiment. * The information is usually written into an easily readable chart called a data table * Data can be analyzed in many ways **Write this

Graphs to analyze Data Graphs are commonly used to analyze data. Data is often organized into graphs which can help show relationships between variables. Graphs show relationships between variables ** **Write this

How to graph Be sure to title your graph…the title represents what the graph is all about. The title should be labeled at the top of the graph. The “Y” axis should be labeled with the Dependent Variable. The “X” axis should be labeled with the Independent Variable.

Title of the graph Ex. “ Effect of water on plant growth” Independent Variable (X-axis) Ex. Amount of Water (ml) Dependent Variable (Y-axis) Ex. Plant Growth (mm) **Write this

Graph relationships Direct Relationship Increasing X results in an increase in Y Ex. As time studying increases, test scores increase. **Write this

Graph Relationship Indirect Relationship **Write this Increasing X results in Y decreasing ** Ex. As time increases, eyesight ability decreases

Graph Relationship Constant Relationship If X is increased, Y stays the same (unaffected) ** Ex. As time spent reading Shakespeare is increased, the students test score on the Scientific Method remains the same **Write this

Graph Relationship Cyclic A repeating pattern Ex. As time of day is increased, amount of light increases, then decreases. **Write this.

Step #6 Draw Conclusions Explain your results from the experiment. Did it support your hypothesis??? If not, why not? Includes: ** -Restate problem and hypothesis -Inferences -Data to back up inferences -Possible problems with experiment design -What you would do next? (change hypothesis and retest?, study another aspect of the problem?) **Write this

What makes a good experiment? Only one independent variable! ** The rest must remain constant. Ex. You can’t test the effect of light and water on plant growth at the same time. **Write this

A good experiment Your experiment is well thought out and planned. You are able to tell how you will change the independent variable. And how you will measure the dependent variable

A good experiment The constants should remain unchanged

Has multiple trials –Repeating the experiment eliminates error. ** Has large sample sizes –If we test more “subjects,” we can be more sure the results are real. ** A good experiment **Write this

YIPPIEEEEEEEEEE Lets do an experiment!!!