Raytheon Engineers

Comparison Scientific Method and Engineering Design Process

The Scientific Method The Engineering Design ProcessState your question Define the problemDo background research Do background researchFormulate your hypothesis, identify variables Specify requirementsDesign experiment, establish procedure Create alternative solutions, choose the best one and develop itTest your hypothesis by doing an experiment Build a prototypeAnalyze your results and draw conclusions Test and redesign as necessaryCommunicate results Communicate results

Steps of the Scientific Method

Scientific Method Steps

1. Ask a Question: The scientific method starts when you ask a question about something that you observe: How, What, When, Who, Which, Why, or Where? – And, in order for the scientific method to answer the question it must be about

something that you can measure, preferably with a number.2. Construct a Hypothesis: A hypothesis is an educated guess about how

things work:"If _____[I do this] _____, then _____[this]_____ will happen.“– You must state your hypothesis in a way that you can easily measure, and of

course, your hypothesis should be constructed in a way to help you answer your original question.

• Conducting a fair test is one of the most important ingredients of doing good, scientifically valuable experiments. To insure that your experiment is a fair test, you must change only one factor at a time while keeping all other conditions the same.

Scientific Method Steps3. Test Your Hypothesis by Doing an Experiment: Your experiment tests

whether your hypothesis is true or false. It is important for your experiment to be a fair test. You conduct a fair test by making sure that you change only one factor at a time while keeping all other conditions the same.– Write the experimental procedure like a step-by-step recipe for your science

experiment. A good procedure is so detailed and complete that it lets someone else duplicate your experiment exactly!

– Repeating a science experiment is an important step to verify that your results are consistent and not just an accident.

• For a typical experiment, you should plan to repeat it at least three times (more is better).

• If you are doing something like growing plants, then you should do the experiment on at least three plants in separate pots (that's the same as doing the experiment three times).

• If you are doing an experiment that involves testing or surveying different groups, you won't need to repeat the experiment three times, but you will need to test or survey a sufficient number of participants to insure that your results are reliable. You will almost always need many more than three participants!

Scientific Method Steps

4. Analyze Your Data and Draw a Conclusion: Once your experiment is complete, you collect your measurements and analyze them to see if your hypothesis is true or false.

– Scientists often find that their hypothesis was false, and in such cases they will construct a new hypothesis starting the entire process of the scientific method over again. Even if they find that their hypothesis was true, they may want to test it again in a new way.• Review your data. Try to look at the results of your experiment with a critical eye. Ask yourself

these questions: – Is it complete, or did you forget something? – Do you need to collect more data? – Did you make any mistakes?

• Calculate an average for the different trials of your experiment, if appropriate.• Make sure to clearly label all tables and graphs. And, include the units of measurement (volts,

inches, grams, etc.).• Place your independent variable on the x-axis of your graph and the dependent variable on

the y-axis.

Scientific Method Steps

5. Communicate Your Results: To complete your science fair project you will communicate your results to others in a final report and/or a display board. Professional scientists do almost exactly the same thing by publishing their final report in a scientific journal or by presenting their results on a poster at a scientific meeting.– Your final report will include these sections:

• Title page. • Abstract. An abstract is an abbreviated version of your final report. • Table of contents. • Question, variables, and hypothesis. • Background research. This is the Research paper you wrote before you started your

experiment. • Materials list. • Experimental procedure. • Data analysis and discussion. This section is a summary of what you found out in

your experiment, focusing on your observations, data table, and graph(s), which should be included at this location in the report.

• Conclusions.

Let’s Set Up the Teams

• Team Organization• Team Name

– Collaborate on the Name• Team Lead

– Appoint 1 person

Think Fast• Abstract

– Are you a piano player or a video gamer? Then you might have a quick reaction time that can come in handy while playing sports. Find out how to measure your reaction time and compare it to your friends and family with this fun experiment.

• Objective– In this experiment, you will measure the reaction time of a person by catching a

metric ruler.• Introduction

– Has anyone ever said, "Think fast!" and then thrown something at you? How quickly or slowly you react is called your reaction time. Your reaction time will be measured by how long it takes for your eyes to tell your brain that the ruler is falling and then for your brain to tell your fingers to catch it (Zoom, 2006). The ruler falling is called a stimulus and this type of reaction is called a simple reaction. The simple reaction time is the time it takes to react to a simple stimuli - or small change in the environment (Wikipedia contributors, 2006).

– In this experiment, you will measure your reaction time by catching a metric ruler with your fingers. After you catch the ruler, you will convert your measurement in centimeters into a reaction time measured in milliseconds. To do this, you will need to use the following reaction time table

Think Fast – Material / People• Material

– metric ruler with centimeter marks – table and chair – paper and pen for charting results – Notebook to document and out brief results

• People– One material distributor and completed sheet runner– One Ruler dropper– 2 Ruler measure– 2 graph readers– 1 distance and time recorder– 2 average calculators

Think Fast – Reaction Time TableDrop Distance Reaction TimeInches cm ms

1 2.5 722 5.1 101.83 7.6 124.74 10.2 1445 12.7 1616 15.2 176.47 17.8 190.58 20.3 203.69 22.9 21610 25.4 227.711 27.9 238.812 30.5 249.413 33 259.614 35.6 269.415 38.1 278.816 40.6 28817 43.2 296.918 45.7 305.5

Think Fast – Reaction Time Graph

What is Our Hypothesis?

Think Fast -Experimental Procedure1. Sit in a chair with your arm resting on a table so that your wrist hangs off the

edge. Your friend should hold the ruler so that it dangles above your hand. Make sure the "zero" end of the ruler is hanging between your thumb and finger.

2. When your friend lets go of the ruler, try to catch it between your thumb and finger as quickly as you can.

3. Mark the ruler where you caught it (top of the thumb). This will be your first measurement, or trial #1. Write down the measurement in a data table.

Trial #1 Trial #2 Trial #3 Average Reaction Time

Name Age Gender R or L ruler (cm) time (s) ruler (cm) time (s) ruler (cm) time (s) Seconds

0

0

0

0

0

0

0

0

Think Fast -Experimental Procedure4. Compare the marking on the ruler where your fingers caught it to the

reaction time chart above. Write down your reaction time in the data table.

5. Repeat steps 1–4 two more times, for trial #2 and trial #3. Did your reaction times vary a lot or were they pretty much the same from trial to trial?

6. Calculate the average reaction time. Add together your three times and divide the answer by 3. Write the average reaction time in your data table.

7. Repeat steps 1–6 for your friend, and any other volunteer you would like to test.

8. Draw a bar graph to present your data. Along the left side of the graph (Y-axis) write the times from the reaction time chart. Across the bottom of the graph (X-axis) write the names of yourself and your volunteers separate columns. Draw a bar for each person up to the number that matches their average reaction time in seconds.

9. Who has the best reaction time?

Results / Out brief / Conclusion