Connection to Lab Report Scientific Method Connection to Lab Report

The Scientific Method

The Truth About The Scientific Method They are not all exactly the same. Main purpose: to serve as a guide to design and perform experiments. Minimize experimental errors and eliminate bias. Increase confidence in accuracy of results.

Making Observations/ Make an Inference Receiving knowledge of the outside world via our senses: Sight Sound Taste Smell Touch Observe something of a natural phenomenon, something that you can’t explain. Inference – propose an explanation, make a conclusion as to why you think something is happening.

Research Creation of a Hypothesis What is the importance of research? Don’t want to conduct an experiment that someone else has already done. Can use another experiment as guidance, perhaps that experimenter didn’t consider a variable that you have. You have identified your problem; make a prediction. Create your hypothesis for your experiment. If __I.V.___, then __D.V.___, because _________________.

Indicate in your hypothesis what you will test. Independent variable – manipulated variable, variable that is deliberately changed. MUST change 1 variable at a time. Dependent variable – measured value that is changed because of the Independent variable. May measure more than 1 variable Controlled variables – variables that we want to remain unchanged, such that the dependent variable is the only variable measured. Prevents misleading data and a relationship between I.V. and D.V. to be acknowledged.

Identify the I.V. and the D.V. Scientific Questions: How does the amount of nitrogen in fertilizers effect plant growth? I.V. = different brands of fertilizers with varying % compositions of nitrogen D.V. = plant growth; plant height, number of leaves per plant, number of plants growing. Controls = amount of sunlight and water the plants receive

Identify the I.V. and the D.V. Scientific Question: Which paper towel absorbs the most? How are we going to conduct this experiment? What variable are we going to change/control? What variable(s) are we going to measure? What variables do we hold constant?

Identify the I.V. and the D.V. Scientific Question: Does television violence increase aggression in children? How are we going to conduct this experiment? What variable are we going to change/control? What variable(s) are we going to measure? What variables do we hold constant?

Identify the I.V. and the D.V. Scientific Question: Does heating a cup of water allow it to dissolve more sugar? How are we going to conduct this experiment? What variable are we going to change/control? What variable(s) are we going to measure? What variables do we hold constant? EVEN MORE: Think about units of measurement. Must be consistent throughout experiment.

How do you plan to test your hypothesis? Devise a procedure; a system of clear, concise, AND specific steps that guide you through testing your hypothesis. Your procedure should give you results that you can observe and measure. Third person. Example: Heat the crucible strongly for one minute. Allow it to cool to room temperature. Weight the crucible (don’t forget to press “tare” first). Record the mass in the appropriate space below. Place a 2 - 3 g sample (one spoonful) of the powdered hydrate into the crucible. Immediately measure the mass of the crucible containing the hydrate. Record your value in the space below. You have created a hypothesis; what are you are going to study. If (state the IV), then (state the DV), because. You need to now figure out how you are going to test your hypothesis

Data Collection & Data Analysis Gathering and measuring variables (I.V. & D.V.) of interest in an organized manner. Tables, graphs, visuals Consider accuracy. How close to the true value? May involve utilizing research. Calculating % Error. Increasing trials improves reliability of results. Ensures results are not altered by random events.

9. Interpreting Data Qualitative Deals with descriptions. Data can be observed but not measured. Colors, textures, smells, tastes, appearance, beauty, etc. Qualitative → Quality Quantitative Deals with numbers. Data which can be measured. Length, height, area, volume, weight, speed, time, temperature, humidity, sound levels, cost, members, ages, etc. Quantitative → Quantity 

Data Example: Oil Painting Qualitative or Quantitative? picture is 10" by 14" with frame 14" by 18" weighs 8.5 pounds surface area of painting is 140 sq. in. cost $300 Qualitative or Quantitative? blue/green color, gold frame smells old and musty texture shows brush strokes of oil paint peaceful scene of the country masterful brush strokes

Qualitative or Quantitative? Qualitative or Quantitative? Data Example: Latte Qualitative or Quantitative? robust aroma frothy appearance strong taste burgundy cup Qualitative or Quantitative? 12 ounces of latte serving temperature 150º F. serving cup 7 inches in height cost $4.95

Data Example: Freshman Class Qualitative or Quantitative? 672 students 394 girls, 278 boys 68% on honor roll 150 students accelerated in mathematics Qualitative or Quantitative? friendly demeanors civic minded environmentalists positive school spirit

Drawing Conclusions Did the conduction of the experiment prove anything? Do the results support the hypothesis? If not, indicate potential errors. Suggest alterations to the experiment? Where there any other factors which might have influenced the outcome of the experiment? Would you get the same results if you did the experiment again? Are there other ways that you could test your hypothesis? Does the data show any patterns? What relationships can you infer from the data?

Complete Fundamentals of Experimental Design POGIL