Dr. Shawn's Super Science Project Support Blog

What is the "Scientific Method"

The scientific method is how scientists do what scientists do to find reliable answers to their questions about how nature works. Basically, the scientific method is the process that scientists most often use to make sure they aren't fooling themselves.

The scientific method involves the following steps: investigating something that interests you, identifying the problem, making your best guess about what the solution might be, devising a test to see if you can prove the guess WRONG (scientists don't try to prove themselves right! They know that making sure they aren't fooling themselves means trying to prove their guesses wrong). Then you must carry out your test, and finally you must analyze your results and reach a conclusion.

Investigation: Investigation is the process of gathering information about something that interests you from every reliable source that you can find. These sources can include your own experiences, respected experts, printed and web-based resources, or the results of experiments done by others. Ultimately, this research should lead you to learn about something you don't understand, or to a question you have that doesn't seem to be answered by anything you've learned about. It is from these questions that you will select your science fair project idea.

Question/Hypothesis: The question you select to answer must be one that both interests you and is very narrowly focused. It should be an open-ended question, that is, one that is answered with a statement, or better, a graph, rather than a simple yes or a no. For example, "How does temperature affect the reproduction of beer yeast?"

Note how narrowly focused this question is. It's about the life process of yeast—reproduction; one type of yeast—beer yeast; and one factor that affects its growth—temperature. To find the answer to a broader question such as "How does temperature affect yeast?" you would have to test different life processes and lots of different types of yeasts.

Hypothesis: A hypothesis is your best educated guess about what the answer to your question is likely to be. And of course, you can't make an educated guess without an education. Your hypothesis has to be based on your knowledge, experience and/or the research you did about the subject that lead to your question.

Personally, I do not think that students should be required to state a hypothesis for their experiment. Many times, when entering some new area of research, scientists have very little idea about what result a new experiment may produce. Their attitude is "Let's do this and see what happens." A hypothesis is NOT essential to an experiment. Worse, it changes the focus of the experiment from answering an open question, to defending a their opinion. And that often leads students to fit the facts to their opinions, instead of fitting their data to their question. In short, it leads to dogma over data, instead of data over dogma.

However, if your science fair competition insists that you formulate a hypothesis, then make your best guess, then try your darnedest to prove that guess wrong! If you have absolutely no idea what will happen, then let your guess be the "null hypothesis"--the most boring possible hypothesis--the guess that the variables you are testing in your experiment are not related. That is the best way to make sure you are not fooling yourself.

Whatever you do, don't change your hypothesis even if data do not support it. If you've disproved your hypothesis--good for you! You've got the makings of a real scientist! If time permits, repeat or redesign to verify your refutation and the judges will really take note of your work.

Do the experiment!

Of course, the experiment is the process you go through to answer your question or challenge your hypothesis. You take data to see how different things are related. Anything you decide to measure in your experiment is called a variable, (meaning "something that can change"). There are three kinds of variables that you must to identify in your experiment: independent, dependent, and controlled.

The independent variable whatever you decide to change in your experiment. The dependent variable is the variable you monitor to see how it responds to that change. A controlled variable is one that you make absolutely certain not to change during the experiment. It's important to only allow one variable to change at a time so we can isolate how one thing affects one other thing. It is only be studying these simple on-against-another kinds of interactions that we can wrap our minds around exactly what's going on.

Looking at our example of temperature on beer yeast, the independent variable is temperature and the dependent variable is yeast reproduction.

Control Experiments: Often, scientists need to do mini experiments before they do their main experiment to make sure they don't get blindsided by other conditions in the experiment. One important mini test is called a "control experiment" in which the independent variable is kept constant in order to identify other things that can cause the dependent variable to change. In a control, you set up the experimental you intend to do, but you don't allow your independent variable to change. Instead, you allow other parts of the experiment to change (for example, the amount of light that falls on the yeast). Doing control tests allow you to know how hard you have to struggle in your experiment to keep these variables constant. For example, if you discovered that the yeast growth rate wasn't much affected by atmospheric pressure, then you know you wouldn't have to worry if a storm front moved it. However, if you discovered that the grow rate was affected by light, then you'd want to make sure that you didn't expose the yeast to enough light during your main experiment to affect the results.

In principle, there are many variables that want to do control experiments to study; humidity, air pressure, light, temperature, and so on. There is no way you are going to be able to test them all. Those that you can't test you'll want to keep as constant as you reasonably can, and then note what you did in your logbook. No science fair judge could possibly expect you to conduct every possible control experiment. Professional scientists don't. Rather, they rely on their experience to tell them what variables they need to control and which are less important.

Another thing, don't just assume you everything right the first time. If you want to make sure you're not fooling yourself you need to repeat the experiment a couple of times to verify that you get essentially the same result every time. If not, then your results are being affected by some subtle variable that you haven't controlled for properly. Chasing these down can be a frustrating exercise, but it is here that you'll really learn the artistry of the scientist.

Conclusion: The conclusion is a summary of the results of your experiment and your final statement of how the data bare on your question or hypothesis. If the data prove your hypothesis wrong (scientists say "falsify the hypothesis") then great! If you see how others could take this work further, make sure end by pointing out how. Namely, say what independent variable you'd use next time, what you would be careful to control, and what change you'd be looking for in the dependent variable.

Dr. Shawn

For more FREE help, visit my Super Science Project Support Site. Check out my collection of killer science fair project downloads. Are you running out of time? Check out my Desperation Science Projects for complete science project instructions that can be carried out in just one day! Or, better, have a complete science experiment sent directly to your home for professional results fast! And, of course, you'll find plenty of science project ideas at my science project idea bank, or my student-driven science project idea exchange.

How to "Connect the Dots" on a Graph

Nearly all science projects require at least one graph to display their results in a clear and convincing way. Once you have plotted your data you will need to connect the dots in a way that displays the underlying connection, if any, between your independent variable (whatever you change in your experiment) and your dependent variable (whatever changes in response). Here are a few tips about how to do that.

Suppose you plot your data with the errors bars and it looks something like this.

(Click on the picture to enlarge it.) You can see that the yield of whatever this graph refers to increases with temperature. How do you connect the dots?

First, NEVER simply connect the dots with a ruler like this.

(Click on the picture to enlarge it.) Every measurement you make is subject to experimental errors and so each datum you take will have error associated with it, meaning that it is unlikely to lie exactly where it should. A few of your data points might be pretty close to where then should be, but you'll measure some to be a little above or below their their true position simply because the no measurement process is perfect. The curve you want to draw needs to be the best estimate you can make of the underling trend that produced the data. It needs to a smooth continuous line or curve that the data is centered around.

OK, so what line or curve should you try first? Answer: The first function you should try to fit the data on any graph is ALWAYS A STAIGHT LINE.

Here's the same data with the best straight line I could plot by eye, without the use of complex mathematics or a computer.

(Click on the picture to enlarge it.) This is actually a pretty good fit. Note that although this line actually touches all the vertical error bars, this need not have been the case. Your error bars are not absolute bounds on your data.

Let me repeat that since no many students do are completely confused about this.

YOUR ERROR BARS ARE NOT ABSOLUTE BOUNDS ON YOUR DATA. In fact, about 1/3 of your data an be expected to be located more than one error bar away from the best fitting curve.

If you can find a line that fits your data then you are done. Never try complex curves or functions when a straight line will do. Why not? Ockham's Razor again... a simple straight line is about the most boring relationship you can imagine. So if a straight line fits the data, then you must take that as the best explanation of your data.

Dr. Shawn

For more FREE help, visit my Super Science Project Support Site. Check out my collection of killer science fair project downloads. Are you running out of time? Check out my Desperation Science Projects for complete science project instructions that can be carried out in just one day! Or, better, have a complete science experiment sent directly to your home for professional results fast! And, of course, you'll find plenty of science project ideas at my science project idea bank, or my student-driven science project idea exchange.

Ockham's Razor and the "Most Boring Hypothesis"

Remember that doing science is all about not fooling yourself. With that in mind, consider this. Suppose you see a situation where there are two different plausible explanations for a given set of facts that have been very well established. This may be in your own science experiments, or anywhere else in any sphere of your life. How do you decide which of the competing theories to accept as your working hypothesis, that is, the hypothesis that you hold as the one that is more likely to be closest to the Truth?

Experience teaches the following remarkable fact: If you always prefer the more boring hypothesis you'll turn out to be right far more often than not. This rule of preferring the most boring hypothesis is so famous that it even has a name. We call it Ockham's Razor.

Here's an example. Suppose when you step out of the shower you are startled see what looks like a ghostly pattern of baby footprints standing out in the condensation on your bathroom mirror. One hypothesis you might consider is that your house is haunted and that some departed spirit is trying to send you a message. Another hypothesis is that a family member is playing a trick on you. Since no one has ever been able to scientifically establish that ghosts exist, (and there is plenty of reasons to suspect that they don't) the ghost hypothesis is a pretty remarkable one. But clearly your family members do exist. And even if no one ever played a trick on you before, and even if everyone in your family denies doing it, the notion that someone is trying to trick you now is clearly a far more boring explanation than that you've been visited by a spirit from the Great Beyond. Therefore, the you should accept the practical joke explanation as the one that is most likely to be the correct one.

That's not to say that strange or remarkable ideas are always wrong. There certainly have been circumstances when truly bizarre theories like Quantum Mechanics and Continental Drift were eventually favored by the data. (And the moment they were, Ockham's Razor required the scientists of those times to change their minds and accept the newer idea as the one closer to the Truth.) But these cases are very rare and as we learn more and more about the Universe, they tend to happen less and less often. So Ockham's Razor really does gives you very useful tool to use in your science, and everywhere else in life, that will enable you to be on the right side of a debate far more often than not.

Dr. Shawn

For more FREE help, visit my Super Science Project Support Site. Check out my collection of killer science fair project downloads. Are you running out of time? Check out my Desperation Science Projects for complete science project instructions that can be carried out in just one day! Or, better, have a complete science experiment sent directly to your home for professional results fast! And, of course, you'll find plenty of science project ideas at my science project idea bank, or my student-driven science project idea exchange.

How Many Trails Per Experiment?

Remember, doing science is all about not fooling yourself and each data point you plot on your graph represents one trail. (A trail is a mini-experiment within your whole experiment to pin down one value of whatever you are testing [the dependent variable] against one value of whatever quantity you are changing in your experiment [the independent variable].) That's why scientists pull together all the trials they have done in their science experiment and plot them on a graph. Graphs allow you to see at a glance exactly how the dependent variable is affected the independent variable. (For example, growth rate vs. concentration of fertilizer.) Graphs paint a clear picture that is easy for anyone to understand. And that is exactly why they are used so frequently in science.

So one of the basic questions you must answer in order to design your science experiment is this: Just how many trails will you need to answer your experimental question? This advice should guide you.

Rule of Thumb #1: In general, for most experiments in which you are studying how one variable depends on another, you should conduct as many trails as you reasonably can. Of course, you want to change the independent variable enough to cause a measurable change in the dependent variable, but beyond that it's good to get as much data as you can to the limits of your time, money, materials and patients. Your patients is a very think for you to keep in mind. Whatever you do, don't set out to conduct so many trails that you overwhelm yourself with work. That's a good way to destroy your interest in your science project, and nobody wants that!

Rule of Thumb #2: Spread your measurements out evenly between the smallest value of the independent variable, and the largest value you are testing. For example, if your independent variable starts at zero and goes to say 100 units, you might select the values 0, 20, 40, 60, 80, and 100 to test. This strategy provides the best way to establish the relationship between the independent and dependent variables over the range of values you are studying in your experiment.

Rule of Thumb #3: Whatever you do, make sure you conduct at least 5 trails. This should not only be able to establish whether or not the dependent variable changes in some regular fashion with the independent variable, it should also let you see if the data fall along a straight line or a curve.

Dr. Shawn

For more FREE help, visit my Super Science Project Support Site. Check out my collection of killer science fair project downloads. Are you running out of time? Check out my Desperation Science Projects for complete science project instructions that can be carried out in just one day! Or, better, have a complete science experiment sent directly to your home for professional results fast! And, of course, you'll find plenty of science project ideas at my science project idea bank, or my student-driven science project idea exchange.

How Many Measurements Per Trial?

Remember, doing science is all about not fooling yourself. And so rather than trust our crude and imprecise senses, scientists make measurements. In fact, nearly all science projects absolutely require them. If you're trying to find out how fast plants grow vs. the amount of fertilizer you are giving them, or discover how the temperature of a water bath changes as salt crystals dissolve inside it, or unravel the metabolism of an insect as its diet is varied, you are going to need to make measurements. And probably lots of them!

Each data point that you might plot on your graph represents one "trail." A trail is a mini-experiment within your whole experiment. Sometimes the method you have to measure something just isn't very precise and so you have to repeat the same measurement a number of times to get a number you can have confidence in to plot on your graph. The question here is, how do you know how many measurements you need to make for each trial and how to you find the number to plot?

Here are a couple of rules to guide you.

Simple Trial: You need to determine the value of some physical property of just one single thing: Its weight, or pH, or height--at some time during your experiment. The number of measurements you need to make depends on how accurately you can determine the value.

Rules of Thumb: For example, if you have high confidence that every single measurement you make is accurate to within about one percent or so, measure the quantity twice--just to be certain you get the value both times. That's a good check to make sure you didn't make a mistake If when you make the same measurement a few times in a row you find that find that you find that the answers are always close--say within about 5 percent of each other-- then measure the quantity three times and use the average of those three measurements as your data point. (To calculate an average you simply add the numbers to together and then divide by the number of measurements you added.) If successive values vary by more than five percent, then measure the quantity least five times and take the average.

(Exception: If you are looking for very small changes in something, changes on the order of one percent or less, you will need a different rule to follow. If so, then you're probably doing something pretty advanced. Since most science fair projects don't need highly precise data, I'll skip the subtle complications that can arise for now.)

Large Trials: You need to measure the same quantity for every member of your test and control group. For example, you are testing a new fertilizer and you have decided to grow 30 test plants and 30 control plants. If you measured the height of each plant three times you'd need to make 180 separate measurements for every trail in your experiment!

Now, I would advise a research scientist who intended to publish their data in a peer-reviewed journal to do just that. But I wouldn't advise a student to work that hard because that kind of drudgery can really kill a young person's budding interest in doing a science project. In fact, I strongly advise students to find the simplest possible way to get a reasonably good answer. If you must make a numerical measurement for each member of your test and control group, then make the measurement once for each member and average over the each group. If this is too much work, then cut your test and control groups down to a more manageable number. It is better that your science experiment to loose sensitivity than for you not finish it. Finally, see if you can find a fast visual way to estimate the average. For example, if you are measuring the heights of plants, try creating a set of horizontal lines along a wall, like what you see behind people in mug shots, and lining the plants along a wall so you can easily compare the height of each plant. With a little practice, you will be able to get a pretty good visual estimate of the average heights at a glance. Make sure you photograph these trials and include each in your science project report in case a judge wants to check your results. (Do you think your desire for a positive result might influence your judgment? [Say, YES!] Then you need to think about how you can control for this possible bias. Why not let a friend with no stake in the outcome make the judgment for you from the pictures?) If you can find a simple way to visually get the information you need, you can save a whole lot of time and get great results!

Dr. Shawn

For more FREE help, visit my Super Science Project Support Site. Check out my collection of killer science fair project downloads. Are you running out of time? Check out my Desperation Science Projects for complete science project instructions that can be carried out in just one day! Or, better, have a complete science experiment sent directly to your home for professional results fast! And, of course, you'll find plenty of science project ideas at my science project idea bank, or my student-driven science project idea exchange.

KYSS Rule--"Keep Your Science Simple" X3

If you want your science project to kick tail at your science fair , then you need a science project idea that you can carry out easily before your science project is due. Remember, your science project idea may not work out the first time (most don't!), so make sure you pick a science project that you could complete at least three times before the due date. The experience you gain when doing your science project the first time will make your science project work better the second time, and if things still don't work out then, you'll still have time to complete your science project again!

Example: Suppose your science project requires two weeks to grow something, but your science fair is just three weeks away, then think carefully before settling on that science project idea. Don't start a two-week science project unless you have at least six weeks before the science fair.

Dr. Shawn

For more FREE help, visit my Super Science Project Support Site. Check out my collection of killer science fair project downloads. Are you running out of time? Check out my Desperation Science Projects for complete science project instructions that can be carried out in just one day! Or, better, have a complete science experiment sent directly to your home for professional results fast! And, of course, you'll find plenty of science project ideas at my science project idea bank, or my student-driven science project idea exchange.

How to Pick the Right Science Project

Since science includes absolutely everything that exists anywhere in the entire Universe, you aught to be able to find something out there that will lead you to a successful science project. It's actually pretty easy if you remember these simple rules.

Rule #1: Your topic doesn't matter much. Unless you're going after the top spot at one of the super elite national science competitions, your choice of project matters a lot less than you might think. Science fair judges are looking for evidence that you understand the methods of science and that you can actually carry out the entire scientific process--hypothesis to conclusion:That is, that you can formulate a testable question, design and implement a solid science experiment and write up an understandable science fair project report. They especially want to see that you understand whatever topic you have chosen, and that you understand the scientific method. Do all that, and you'll probably have a winning project.

Rule #2: Just make sure you've selected a science project. Forgive me, but from my long experience as a science fair judge I know that many students try to do an art project for their science fair! For instance, what does mixing baking soda and vinegar with a little red food coloring have to do with how volcanoes erupt? Answer... absolutely nothing. Yet many science fair students spend a whole lot of time creating a paper masche "volcano" around a soda bottle to deliver that classic but silly payoff. The truth is, the volcano "experiment" is an art project, not a science project, that has no place in a science classroom, let alone a science fair. And there are plenty of other disguised art projects at science fairs as well. How do you tell? ...It's pretty simple. If you haven't made measurements (or reviewed published data) to answer a specific and narrowly defined question, you haven't done a science project. Usually, if there is no graph in the paper, there is no science the project.

Rule #3: (the most important rule of all!) Pick a science project that interests you! I can't emphasize this enough. If your science project doesn't get you excited, then it's the wrong project for you. You've got be interested in something, right? Then you can formulate a narrowly focused question about whatever that thing is, can't you? Well, if that question is one that you could answer in a reasonably short amount of time using stuff that you have ready access to, then you've got yourself a science project. For more hints about selecting your science project idea, check out my 4 Fundamental Rules of science project success.

Dr. Shawn

For more FREE help, visit my Super Science Project Support Site. Check out my collection of killer science fair project downloads. Are you running out of time? Check out my Desperation Science Projects for complete science project instructions that can be carried out in just one day! Or, better, have a complete science experiment sent directly to your home for professional results fast! And, of course, you'll find plenty of science project ideas at my science project idea bank, or my student-driven science project idea exchange.

More About How To Keep a Science Project Notebook

As noted in an earlier post, one of the great rules of doing real science is this: "If it isn't in the lab book, it never happened."

In other words, it isn't enough just to do the experiment. You have to make sure that you have enough information so that all the open questions have been answered and all the problems you encountered while doing your experiment have been solved. In short, you need to leave a record that is so clearly written down and in so well organized that another scientist could follow your notes and duplicate exactly what you did.

So, one of the most important keys to a good any good science project is writing things down clearly and systematically.

And keep in mind that the laboratory notebook is one of the most important tools a scientist has. You see, clear writing requires clear thinking. When you write something down, it forces you to think about your ideas. Very often, just writing something down will help you develop and refine an idea. Not only does will it help make your experiment repeatable, your lab book is a place where you can brainstorm, thrash out ideas, and identify mistakes and false starts. It's important to record the things that don't work, so you--and others who use your notes--can learn from them.

TIP: Keep in mind that lab books are not written for today but for the future.

Don't worry that recording your mistakes will make you look bad to your teacher or the science fair judges. Usually, the opposite is true. Being able to spot a mistake and change your experiment accordingly is a vital scientific skill. Good science means being honest about every aspect of your experiment. Mistakes, missteps and blind alleys are all part of the process, even for the Nobel Prize winners. For this reason, most science notebooks are written in ink.

Don't be too concerned if there are things you don't know. Don't be afraid to write down those issues that you haven't figured out yet. All of science is built on those three magic words: I don't know. Judges in a science fair will not dock you if you don't know everything about your subject. However, they will take off points if you claim to understand things that you really don't understand.

The Notebook

As noted in an earlier post, you need to go to an office supply store or stationary store and pick out a bound quad-ruled (graph paper) notebook with numbered pages. For most projects, a composition book or any other notebook with bound pages (as opposed to a loose-leaf or coil-bound notebook) will do. Write your name and contact information inside the front cover in case it goes missing.

TIP: Write the title of your project on the first page, then leave a blank page before starting your notes. This blank page will become your table of content as you develop your notebook. Also, as you write, put page numbers in the upper or lower corner of each page.

What to Write

Everything you do in the laboratory, library, or out in the field should be recorded in your notebook.

Start with a description of your project, followed by your background research. Before you do a real science project, you need to know something about what you are doing. Are you studying meteors? Bird songs? Fractals? Go to the library and look up these subjects, and write down the books, magazine articles, web sites, etc. you consulted, and what you learned from them.

Next, carefully describe what you are going to do and why your are doing it. If you are doing an experiment, make a clearly and carefully labeled sketch of your project. If you bought items to use in your experiment, make a record of what they were, where you got them, and what they cost. In fact, it's a good idea to paste receipts directly in your lab book. If your work involves nature study out in the field, draw or paste in a map of the area where you are working, photographs of the area, and so on.

Remember, you want someone to be able to take your notes and repeat your work exactly.

Every trial you do should have its own clearly labeled record in your notebook. Start each new trail on a new page. The top of the page should contain the title of the experiment and the date.

TIP: It's a good idea to create your index as you go along. At the end of the day's work, zip back to the index page and write down each new section with the page number. Your index page should look something like this:

Index

Project Description - - - - - - - - page 2
Background research - - - - - - page 3
Project design - - - - - - - - - - - -page 7
Experiment #1 - - - - - - - - - - - -page 12
Experiment #2 - - - - - - - - - - - -page 18

And so on.

Each complete experiment should include the following:

Title/Purpose: Every experiment should have a descriptive title.

Background Information: This section should include any information about the execution of the experiment or to the interpretation of the results. For example, if it is a repeat experiment, state what will be done differently to get the experiment to work. Include anything that will be helpful in carrying out the experiment and deciphering the experiment at a later date.

Materials: This section should list any materials, i.e., solutions or equipment, that will be needed. Include all calculations made in preparing solutions.

Procedure: Write down exactly what you are going to do before you do it and make sure you understand each step before you do it. You should include everything you do including all volumes and amounts.

Writing down a procedure helps you to remember and to understand what you're doing. It will also help you to identify steps that may be unclear or that need special attention.

Some procedures can be several pages long and include more information than is necessary in a notebook. However, it is good laboratory practice to have a separate notebook containing methods that you use on a regular basis. If an experiment is a repeat of an earlier experiment, you do not have to write down each step but refer to the earlier experiment by page or experiment number. If you make any changes, note the changes and why. Flow charts are sometimes helpful for experiments that have many parts. It is good practice to check off steps as they are completed or reagents as they are added to prevent you from losing you place or for forgetting to add something.

Results: This section should include all raw data generated by your experiment. This section should also include your analysis of the data.

Conclusions: This is one of the most important sections. You should summarize all of your results, even if they were stated elsewhere and state any conclusions you can make. If the experiment didn't work, what went wrong and what will you do the next time to try to troubleshoot?

Remember, your notebook is what makes your work into real science. Take you time and do it right. The better your notes, the stronger your science project will be.

by Dr. Shawn and Sheldon Greaves, Ph.D.

For more FREE help, visit my Super Science Project Support Site. Check out my collection of killer science fair project downloads. Are you running out of time? Check out my Desperation Science Projects for complete science project instructions that can be carried out in just one day! Or, better, have a complete science experiment sent directly to your home for professional results fast! And, of course, you'll find plenty of science project ideas at my science project idea bank, or my student-driven science project idea exchange.

Test and Control Groups and the "Null Hypothesis"

Remember, doing a science experiment is all about not fooling yourself.

With that in mind see if this makes sense... To prove that you've made a discovery, you must show that your results are inconsistent with the assumption that nothing special happened in your science experiment. Here's an example. Suppose you feed one group of plants a special fertilizer of your own concoction, and you feed a second group ordinary store-bought fertilizer. If you can prove that the plants that got your special recipe grew faster than the others, then you can rightly claim to have found a better fertilizer. But if they don't, you can't claim to have something better than what's already on the shelves.

Makes sense, right?

Many science experiments are structured in just this way. They have one group that they treat in the "normal" way. Basically, you have one group that you don't do anything special to. We call this the "control group." Then you have a second group that you test out your idea on. We call this the "test group." The most conservative guess you can make about what you'll find is always that nothing special will happen. Scientists call this standard and rather boring guess the "Null Hypothesis." You should only get excited if your experimental results can not be reconciled with the Null Hypothesis. Or using the full jargon of science experiments, in order to claim a discovery you must "falsify the Null Hypothesis."

Doing that usually requires a little bit of statistics. You must know a little about averages and standard deviations, and all that. And I'll explain that stuff to you in a later post. But I can give you one very important rule of thumb that can help you design your science experiment.

Scientists know that the larger their control and test groups are, the more sensitive their science experiment will be. But what if you don't have any idea how large some new effect is likely to be? How many members should your test and control groups have in them? Rule of thumb: About 30.

Keep that in mind. When they don't know how large some effect is likely to be, many scientists conduct their first experiment with 30 members in the test group and 30 members in the control. We've learned from centuries of experience that 30 is a good number to start with. So unless you have a good reason to use a different number, use 30.

Dr. Shawn

For more FREE help, visit my Super Science Project Support Site. Check out my collection of killer science fair project downloads. Are you running out of time? Check out my Desperation Science Projects for complete science project instructions that can be carried out in just one day! Or, better, have a complete science experiment sent directly to your home for professional results fast! And, of course, you'll find plenty of science project ideas at my science project idea bank, or my student-driven science project idea exchange.

How to Record an Observation in Your Lab Book

Remember that your lab book has to be the final word on your science experiment and the judges who will grade your science fair project are going to want to see it. Your goal must be to keep a lab book that is so complete that an expert in your field of science would be able to understand exactly what you did and what results you got simply be reading through it.

In fact, a scientist's motto has to be "If it isn't in the log book, it didn't happen." I strongly suggest you WRITE THAT DOWN at the bottom of page one in quotation marks for two reasons; first as a constant reminder to you of one of the most important cannons of the laboratory; and second because it will really impress the judges. (Trust me!)

Here are a few tips that will help you end up with a real scientist's log book.

First, when writing down an observation, pretend that you are describing what you are observing to a knowledgeable friend over the telephone. If your description is clear enough for your friend to know exactly what you have done, it will be clear enough for the science fair judges as well.

Second, use the squares on the graph paper (is your lab book constructed of bound graph paper, or did you miss that tip?) to form your data tables, and carefully label the columns with very clearly lettered labels. Also, use a ruler to trace the lines that define the table. Don't draw these lines by hand. Nothing irritates a science fair judge more sloppy data tables or not being able to understand why you took the data you did.

Third, clearly label each page with the appropriate page number. And don't forget to date each page! (Note, if you are developing invention that you think you might want to patent, then you need to date and sign each page and write all your notes in pen. This is a legal method of establish priority for you should someone else ever claim that they invented your product first.)

Fourth, set aside the first page of your lab book as the table of contents and make sure every new topic is clearly listed there on page one.

Fifth,if you use a spreadsheet program to generate your graphs (and I strongly suggest you do so), make sure you paste copies into your lab book with a caption the clearly explains what information the graph displays.

Finally, as in all things, neatness counts. A well organized lab book suggests a well organized mind and a well organized experiment. An illegible unkempt notebook is sure to get you docked come judging time.

Dr. Shawn

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