Experimental Design Worksheet s3

Name ______

Introduction to Scientific Method & Experimental Design

Objectives: This is your intro to our Experimental Design Unit. By the end of this unit you should be able to:

· Apply the Scientific Method to a given situation in real life.

· Design a Hypothesis that is in the form of a “If…Then…” statement that is TESTABLE!

· Design an experiment with all necessary components, including an independent variable, dependent variable(s), controlled variables, control group, experimental group, and procedures.

· Collect data from and experiment and analyze it to determine correctness of a hypothesis.

· Evaluate the strength of an experiment based on it deisgn.

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PART I: What is the Scientific Method?

Scientific Method- It is a 6 part, step by step approach to solving a problem/answering questions.

1) State the Problem or Question- A question is asked after observations about something.

2) Gather Information (research)- Information about the problem is collected to become informed.

3) Form a hypothesis- Propose a possible explanation or solution to the problem. Must be a “If…Then…” statement. Your hypothesis should be very clear and exact. Can only be right/wrong.

4) Design Experiment- Design experiment with a control group and a variable group.

5) Do Experiment and Collect Data Conduct an experiment with a control group and a variable group.

6) State a conclusion- Determine whether or not a hypothesis is correct based on data

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Practice I: Below, fill in the rest of the steps of the following example of the scientific method using the info about each step from above…you can make up the answers because this is only hypothetical!

1) State the Problem or Question- Does listening to ______’s music help improve test scores

2) Gather Information- (What info would you gather and how?)

3) Form a hypothesis- (What is your hypothesis?)

4) Design Experiment- (Actually write out how you perform an experiment)

5) Do Experiment and Collect Data- (What data would you collect)

6) State a conclusion- (How would you make a conclusion and what would you address first in the conclusion)

Practice II: Let’s assume you own a gas company that transports 4 types of gas (CO2, Air, Helium, and Hydrogen) and you need to determine which of these gases are flammable. Please try to design an experiment where you could test these 4 gases for their flammability, and design the experiment in such a way that you would be able to test it in class today (which we will). Write out your experiment below.

Think about our experiment, and let’s make a list of the different components that we must consider when we design an experiment so that we are accurately testing the variable. List them in the box below.

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PART II: What is Experimental Design?

Directions: Fill out the boxes below with several things in each box

PART II: What is the Experimental Design?

Experimental Design- describes the manner in which you test your hypothesis through experimention. Having correct experimental design is CRUCIAL to accurately testing your hypotheis. The stronger your experimental design is, the more reliable your results will be, and the more confident you can be when you draw conclusions from your data.

Variables: Scientists use an experiment to search forcause and effectrelationships in nature. In other words, they design an experiment so that changes to one item cause something else to vary in a predictable way. A variable is any factor, trait, or condition that can exist in differing amounts or types. An experiment usually has three kinds of variables: independent, dependent, and controlled.

Independent Variable: this variable is changed by the researcher and observations are made to see if the change of the independent variable has an impact on the dependent variables. Only ONE independent variable should change in an experiment (unless a more complex design is used….we can talk about this later)

Example(s): ______

Dependent Variables: these variables change as a result of the independent variable. The scientist focuses the observations on thedependent variableto see how it responds to the change made to the independent variable. The new value of the dependent variable is caused by and depends on the value of the independent variable. This is where your DATA comes from.

Example(s): ______

Controlled Variables: these are Independent Variables in the experiment that you keep the same (YOU MAKE SURE THEY DON’T CHANGE)

Example(s): ______

Hypothesis: This is developed from your question and should be very clear and direct. Every hypothesis needs an Independent Variable and a Dependent Variable, and should be written as an “If…Then…” statement. The hypothesis is NOT A QUESTION but a statement that can either be correct or incorrect. YOUR HYPOTHESIS MUST BE TESTABLE (meaning you can collect data on it!)

Control Group: this group does not receive the treatment (no change to independent variable). This group is used to compare to as the “normal” or “baseline”.

Example(s): ______

Experimental Groups: this group recieves the treatment (change in independent variable)

Example(s): ______

Trials: the # of times you replicate the experiment.

Data: anything that can be observed/measured in an experiment. Two types of data: quantatative and qualatative.

Example(s): ______

Quantatative Data: anything that can be measured with numbers (24 horses finished the race, Mr. Miller ate 5 pies, the Flyers scored 3.4 goals per game last month, etc.)

Qualatative Data: Obserations not related to quanitites or numbers (examples: the horese is brown, Mr. Miller is drawin’, the Flyers are awesome, etc.)

Example A: The further you sit from Mr. Miller, the less chance you will get caught on your phone.

Hypothesis: If you sit closer to Mr. Miller, then you are more likely to get caught with your phone.

Independent Variable: Distance of your seat to Mr. Miller Dependent Variable: # of times caught w/ phone

Control Group: Back Row Experimental Group: All Rows Closer

Example B: 11th Grade boys do better on Integrated Science tests then girls do.

Hypothesis: If you take an Int. Science test and you are a guy, then your score will be higher.

Independent Variable: Whether Guy or Girl taking test Dependent Variable: Test Score

Control Group: Girls Experimental Group: Guys

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Practice Writing Hypotheses: Write a hypothesis for each of the statements and identify the variables, control group, and experimental group.

#1. Tosh.0 draws a larger audience then the nightly news.

Hypothesis: If ______, then ______