The Scientific Method

The Scientific Method The Scientific Method is a series of steps used answer a question or solve a problem - There are 5 main steps

Step 2: Form a hypothesis Step 1: Ask a Question Step 2: Form a hypothesis Step 3: Perform experiment to test hypothesis Step 4: Analyze results Step 5: Draw conclusions ** Sometimes, 2 extra steps are included :  step 2: collect data and communicate results  last step: communicate results See Lab Safety Package pg. 7-8

The Hypothesis Hypothesis: an educated guess or prediction. It must be testable. We will write our hypothesis using an “if, then, because” statement: If ____independent variable______ then__dependent variable_______ because ___scientific explanation___.

Example: Independent Variable: The amount of food I feed my cat My cat’s weight If ___________________________ then _________________________ because _______________________.

Try to use INCREASE and DECREASE in your hypothesis! Remember Try to use INCREASE and DECREASE in your hypothesis! Ex. IF I increase the amount of food I give my cat, THEN she will increase her weight, BECAUSE there will be an increase in calories.

Writing a good hypothesis. Now Try it on Your Own! ‘Writing a Good Hypothesis” Just ‘plug and chug’ in your variables! Refer to Handout: Writing a good hypothesis.

The experiment: Writing Procedures Let’s brainstorm a few simple tasks that we do on a daily basis. On your own, write a detailed procedure for one of the tasks on our list

The experiment: Identifying Variables There are 2 main types of variables: Independent Variable: The variable that is changed/decided upon by the scientist; Dependent Variable: The variable that might change because of what the scientist is doing– what is being measured

Remember! Your hypothesis can TELL you what your variables are! Ex. If I drink Mountain Dew before bed, then I will not sleep very much because it is high in caffeine. IV: Drinking Mountain Dew DV: the amount of sleep

Identify the variables in the hypothesis statement: Practice Identify the variables in the hypothesis statement: If I brush my cat more, then there will be less fur on my couch because it will be gathered by the brush. IV: ______________________ DV: ______________________

Now read the following experiment and identify the independent and dependent variables Elizabeth wanted to test if temperature affected how fast milk goes bad and curdles. She left milk in a room temperature closet, a fridge, and on the counter in direct sunlight. She then measured how rotten the milk was after 10 days. IV: ____________________________________ DV: ____________________________________

YOUR TURN TO PRACTICE!!! Refer to handouts Examples: DEPENDENT INDEPENDENT Cell phone bill Minutes used How far you can drive The amount of gas you have How much money you earn The hours you work Cost of a speeding ticket How many kilometers you went over the speed limit Time it takes to drive somewhere How fast you drive Result of a football game Who scores more points How much air conditioning you use Temperature Total calories and fat Number of burgers you had YOUR TURN TO PRACTICE!!! Refer to handouts Independent and Dependant Variables A Variable Way to Practice Variables

Constant Constant: something that scientist make sure is the same throughout the experiment Ex. Watering the plants the same amount of water or making sure you are using the same measure tools every time.

Control Control: The part of the experiment that the scientist doesn’t change Ex. One plant will be planted in regular soil while the other plants will get planted in soil and fed with different types of fertilizer. YOUR TURN! Identify the controls and variables (Simpson worksheet)

The experiment: Making Observations While conducting your experiment(s), you will need to make observations. Whenever possible, you should make a table to organize your collected data. There are 2 types of observations: - Quantitative and Qualitative - What is the difference?

The Analysis This is the most important part of your experiment! This section will be taught to you separately  Graphing

The Conclusion The conclusion should state whether your tested hypothesis was correct or incorrect. Even if it was incorrect, what matters is that you try to explain why scientifically. You need to make statements based on your analysis (looking at the graphs). You also need to include sources of error. (Human: miscalculations, reading scales, Mechanical: instrumental- scale or thermometer isn’t accurate)