Scientific Method - Tredyffrin/Easttown School District



Scientific Method – P.R.H.E.A.C

Or

Pretty Red Heads Eat Animal Crackers

Problem: __________________________________________________________.

Ex – How does ___________ affect the ______________ of mice?

Research: ______________________________________________________________

_________________________________________________________________________.

Ex – For the problem above, research might include what you have read about _______in your text and what you research about __________________________..

Hypothesis:____________________________________________. Your hypothesis must be in an ___________ format. Do not use _________________

For example “____________________(____________________) then the (_______________) will (_______________, ____________, or ____________).” Verb tense:_________________.

Ex – If you _______________the amount of ___________you give a mouse, its heart rate will increase.

** In some cases this exact form won’t work, but it should be very close.

For example “If you use red light rather than green light the plant will grow higher.

Examples of common mistakes when writing hypotheses:

← You forget to clearly state how the dependent variable changes.

Wrong – If you change the amount of sugar then the mouse’s heart rate will change.

Right – If you ____________the amount of sugar the mouse’s heart rate will _____________.

← Used “it” instead of stating both the independent and dependent variables. “It” is not specific enough. You must state both variables in the hypothesis.

Wrong – If you increase it, then the mouse’s heart rate will increase.

Right – If you increase_____________________, then the _______________________ will increase.

← You forget to include the type of organism or thing you tested.

Wrong - If you increase the amount of sugar, then the heart rate will increase.

Right - If you increase the amount of sugar, then ___________________________will increase.

← You included an explanation (I think or because) in the hypothesis.

Wrong – If you increase the amount of sugar, then your heart rate will increase because my heart seems to go faster after I drink soda.

Right - If you______________________________________________________________.

Note: In order to correctly create a hypothesis, you need to have a clear idea of what your independent and dependent variables are for the experiment. Refer to the first example of correct and incorrect hypotheses for clarification. You should get into the habit of writing the I.V. and D.V. between the research and hypothesis sections.

Independent Variable (a.k.a.__________________): the variable you ________________ (in the 1st example: the amount of sugar). You must have the power to change or control the IV.

Dependent Variable (a.k.a.___________________): the variable that you _____________________________ because of the independent variable (in the 1st example: the mouse’s heart rate).

Experiment – First section is a bulleted list of _________________you need to do the experiment. The second section is a numbered list of the _____________________that you will be doing. You should try to edit this to be as short as possible. If possible, use the phrase “repeat steps …..” instead of rewriting the steps a second time. Good experiments have the following:

1. At least 2 groups: the ______________group and the __________________ group. You should get into the habit of identifying and writing the control and experimental groups after the materials list.

- Control group – This is the “_______________________” group. This is used to compare what you did with “_________________________-”. Ex – mice that aren’t given sugar.

- Experimental group(s) – This is where you change your __________________________to see what effect it has. You may have several ______________________groups. Ex – mice that are given sugar. You may have several groups with different amounts of sugar in each.

2. Have several _____________or several things per group.

- Be sure to average your trials in your data tables and when you graph!

- In general, more is more accurate, but can be more expensive and time consuming. Usually 3 –5 will be enough. Ex – You might have 5 mice you give sugar to and 5 that you don’t.

3. Only change___________________. Everything else should remain_______________. Ex – You change the sugar, but each group gets the same light, food, water etc. These are called________________.

4. Results should be __________________in lab. When possible they should be ___________________(numbers) not _____________________(descriptive words). Include ________________(g/mL, kg, cm, W, N). Ex – You would need to be able to count the heartbeat on the mice to get the number of heart beats per minute.

Analysis –______________________. It is one of the most important sections and is often the longest.

Must include 3 parts:

1. Data table (NO TAR)

2. Graph (Line graph if possible – HILTC, if not bar graph)

3. Written analysis:

Your analysis should explain what happened, what your results were, a discussion of your inconsistencies (if any) or your confidence in your results and problems you encountered while doing the lab. All four items are detailed on the next page.

1. Describe the relationship between the IV & DV. Say what happened.

A) Statement about how changing the ____affected the ____. Ex – Sugar increase the heart rate of mice.

B) Support your statement with specific __________________________in lab. Refer to your data tables and graphs!

2. Explain your results. Why do you think that this happened? Refer to the key science concepts and terms that might explain your results. Be sure to include your____________. Ex – The reason that the mouse’s heart rate went up after it ate sugar was that the sugar gave the mouse more energy so it was moving around more. The heart had to beat faster to get enough oxygen to the muscles so it could move. Animals get their energy by breaking down the food they eat into glucose during the process known as cellular respiration.

3. How confident are you with your results? Did you find any___________________? If so, what do you think happened to cause the inconsistency? Be sure to include your thought process. Ex – If all of your mice in the control group had a heart rate of around 50 and one had a heart ate of 98 this would be an inconsistency. You might think there was something wrong with that mouse, that the person who measured made a mistake, or that you recorded your information in the wrong spot.

4. How could you improve or extend this lab? This may include problems in the design of the lab or in carrying it out. Do NOT blame anyone else if your lab did not go well. Assume responsibility for how the lab went. . If you cannot discern a problem with the lab or the results, describe how you could modify the lab in some way to make it more meaningful or to learn more about the topic of study. Be sure to include your thought process. Ex – My partner dropped the mouse and screamed and this may have increased the heart rate. I would improve this lab by handling the mice more carefully. Ex. 2- I would expand out understanding of how sugar affects the heart rate of mice by testing how other chemicals (like starch, caffeine, or artificial sweeteners) affect the heart rate of mice.

What not to include: “This lab was really fun…”

Conclusion: _______ statements. The first tells whether your ______________________was correct or not in the PAST tense. The second is your ________________ rewritten in the PAST tense.

Wrong: My hypothesis was right.

Correct: My hypothesis was correct. Increasing the amount of sugar increased the mice’s heart rate.

Science Definition

The word science comes from the Latin "scientia," meaning knowledge.

How do we define science? According to Webster's New Collegiate Dictionary, the definition of science is "knowledge attained through study or practice," or "knowledge covering general truths of the operation of general laws, esp. as obtained and tested through scientific method [and] concerned with the physical world."

What does that really mean? Science refers to a system of acquiring knowledge. This system uses observation and experimentation to describe and explain natural phenomena. The term science also refers to the organized body of knowledge people have gained using that system. Less formally, the word science often describes any systematic field of study or the knowledge gained from it.

What is the purpose of science? Perhaps the most general description is that the purpose of science is to produce useful models of reality.

Most scientific investigations use some form of the scientific method.

Science as defined above is sometimes called pure science to differentiate it from applied science, which is the application of research to human needs. Fields of science are commonly classified along two major lines: Natural sciences (the study of the natural world) and Social sciences (the systematic study of human behavior and society).

The Different Fields of Science

This is just a partial listing of some of the many, many different possible fields of study within science. Many of the fields of natural science listed here overlap to some degree with one or more other areas.

Biology

• Anatomy

Astrobiology

Biochemistry

Bioinformatics

Biophysics

Botany

Cell biology

Developmental biology

Ecology

Entomology

Epidemiology

Evolutionary biology

Freshwater Biology

Genetics

Immunology

Marine biology

Microbiology

Molecular Biology

Morphology

Neuroscience

Physical anthropology

Physiology

Population dynamics

Structural biology

Taxonomy

Toxicology

Virology

Zoology

Chemistry

Analytical chemistry

Biochemistry

Computational chemistry

Electrochemistry

Inorganic chemistry

Materials science

Organic chemistry

Polymer chemistry

Physical chemistry

Quantum chemistry

Spectroscopy

Stereochemistry

Thermochemistry

Physics

Acoustics

Astrodynamics

Astronomy

Astrophysics

Biophysics

Classical mechanics

Computational physics

Condensed matter physics

Cryogenics

Dynamics

Fluid dynamics

High Energy Physics

Materials physics

Mechanics

Nuclear physics

Optics

Particle physics

Plasma physics

Polymer physics

Quantum mechanics

Solid State physics

Thermodynamics

Earth Science

Environmental Science

Geodesy

Geography

Geology

Hydrology

Meteorology

Oceanography

Paleontology

Seismology

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All data on this page taken directly from: 2-Sept-09

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In order to avoid copyright disputes, this page is only a partial summary.

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