Scientific Method

Scientific method

The scientific method is a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge.

Example of Purpose/Question

• Does music affect on animal behavior?

• Does the color of food or drinks affect whether or not we like them?

• Where are the most germs in your school?

• Does music have an affect on plant growth?

• Which kind of food do dogs (or any animal) prefer best?

• Which paper towel brand is the strongest?

• What is the best way to keep an ice cube from melting?

• What level of salt works best to hatch brine shrimp?

• Can the food we eat affect our heart rate?

• How effective are child-proof containers and locks.

• Can background noise levels affect how well we concentrate?

• Does acid rain affect the growth of aquatic plants?

• What is the best way to keep cut flowers fresh the longest?

• Does the color of light used on plants affect how well they grow?

• What plant fertilizer works best?

• Does the color of a room affect human behavior?

• Do athletic students have better lung capacity?

• What brand of battery lasts the longest?

• Does the type of potting soil used in planting affect how fast the plant grows?

• What type of food allow mold to grow the fastest?

• Does having worms in soil help plants grow faster?

• Can plants grow in pots if they are sideways or upside down?

• Does the color of hair affect how much static electricity it can carry? (test with balloons)

• How much weight can the surface tension of water hold?

• Can some people really read someone else’s thoughts?

• Which soda decays fallen out teeth the most?

• What light brightness makes plants grow the best?

• Does the color of birdseed affect how much birds will eat it?

• Do natural or chemical fertilizers work best?

• Can mice learn? (you can pick any animal)

• Can people tell artificial smells from real ones?

• What brands of bubble gum produce the biggest bubbles?

• Does age affect human reaction times?

• What is the effect of salt on the boiling temperature of water?

• Does shoe design really affect an athlete’s jumping height?

• What type of grass seed grows the fastest?

• Can animals see in the dark better than humans

• Does caffeine speed up your heart rate?

• Which type of orange gives more juice when squeezed?

• What types of food do mealworms prefer?

• Which sweets do ants like best?

• Which brand of battery will last longer in a flashlight

• Which type of fabric lets the least amount of water flow through it?

• Which materials hold heat the longest?

• How do salt or sugar affect the boiling point of water?

• How does oxygen affect how fast a candle will burn?

• Do different surfaces affect how far a marble will roll when released from a ramp?

• Does the shape of a parachute affect its fall time?

• Which metal heats up the fastest?

• Which type of fabric dries the fastest?

• What happens to a balloon when it is pushed under warm or cold water?

• Do different liquids affect the surface tension of water?

• Does a left handed person throw more sixes with dice than a right handed person?

• Which plant food makes bean seeds grow the fastest?

• Does the size of a piece of fruit affect how many seeds it has inside?

• How much water do plants need to grow?

• Does bacon with more fat shrink more or less than bacon with little fat?

• Can you separate different fluids?

• In which liquid will ice cubes melt the fastest?

• Which liquid cleans a penny the best

• Which liquid dissolves an aspirin the fastest?

• Which type of cup keeps water coldest longest?

• Does temperature affect the way ants behave?

• Are insects affected by different amounts of light?

• How far does a snail travel in one minute?

• Do different types of soil hold different amounts of water?

• Will adding bleach to the water of a plant reduce fungus growth?

• Does the shape of a kite affect its flight?

• Does an ice cube melt faster in air or in water?

• Does the color of water affect its evaporation?

• Will water with salt evaporate faster than water without salt?

• Do all colors fade at the same rate?

• Will more air inside a basketball make it bounce higher?

• Does the color of light affect plant growth?

• Using a lever, can one student lift another student who is bigger?

• Does the physical size (at the same wattage) of a light bulb affect its energy use?

• Which metal conducts heat best?

• Which type of material heats/cools fastest?

• Does an earthworm react to light and darkness?

• Do sugar crystals grow faster in tap water or distilled water?

• Is using two eyes to judge distance more accurate than using one eye?

• Do different kinds of caterpillars eat different amounts of food?

• Does a plant need some darkness to grow?

• What are the effects of chlorine on plant growth?

• Do bigger seeds produce bigger plants?

• On which surface can a snail move faster—dirt or cement?

• Do ants like cheese or sugar better?

• Can the design of a paper airplane make it fly farther?

• Do roots of a plant always grow downward?

• Does temperature affect the growth of plants?

• Does warm water freeze faster than cool water?

• Which dissolves better in water—salt or baking soda?

Those look like pretty good questions to research because they would enable us to make some predictions about an experiment. But what's that column in the table called "Relevant?"

You can always find more information to research, but some questions just don't have anything to do with the experiment you will define and perform. Questions that will help you design and understand your experiment are called relevant. Questions that will not help you design and understand your experiment are called irrelevant. Our table of question words is a great way to generate ideas for your background research, but some of them will be irrelevant and we just throw those out. Some of those irrelevant questions might be very interesting to you; they just don't belong as part of your science fair project. We have to focus our efforts on what we feel is most important, or another way of looking at it, let's not spend time researching anything we don't need to. (I'm sure you have other things you'd like to do, too!)

For a good example of how the question word table can generate irrelevant questions, let's just look at some possible questions if we fill out the table for another one of our sample keywords: milk.

• Why does milk happen?

• How does milk happen?

• Who needs milk?

• What causes milk to increase (or decrease)?

• What is milk composed of?

• What are the properties and characteristics of milk?

• Where does milk occur?

If we research every one of those questions we'll be studying farms, cows, cow udders, baby cows, and what cows eat. Holy flying cows! That information is definitely irrelevant to our science fair project question: Does drinking milk help decrease spiciness better than water or Pepsi?

Even so, in that crazy list of cow science, there are two questions that look relevant for your background research:

• What is milk composed of?

• What are the properties and characteristics of milk?

Sometimes you won't be sure whether a question is relevant or not, and that's always a good time to get the opinion of more experienced people like your mentors, parents, and teachers. In fact, the background research plan is a very important step of your science fair project and two or three heads are always better than one! Even with all that help, you may not be sure whether something is relevant until after you have done your experiment, so don't let it bother you if that's the case.

What is a Hypothesis?

A hypothesis is a tentative, testable answer to a scientific question. Once a scientist has a scientific question she is interested in, the scientist reads up to find out what is already known on the topic. Then she uses that information to form a tentative answer to her scientific question. Sometimes people refer to the tentative answer as "an educated guess." Keep in mind, though, that the hypothesis also has to be testable since the next step is to do an experiment to determine whether or not the hypothesis is right!

A hypothesis leads to one or more predictions that can be tested by experimenting.

Predictions often take the shape of "If ____then ____" statements, but do not have to. Predictions should include both an independent variable (the factor you change in an experiment) and a dependent variable (the factor you observe or measure in an experiment). A single hypothesis can lead to multiple predictions, but generally, one or two predictions is enough to tackle for a science fair project.

Examples of Hypotheses and Predictions

What if My Hypothesis is Wrong?

What happens if, at the end of your science project, you look at the data you have collected and you realize it does not support your hypothesis? First, do not panic! The point of a science project is not to prove your hypothesis right. The point is to understand more about how the natural world works. Or, as it is sometimes put, to find out the scientific truth. When scientists do an experiment, they very often have data that shows their starting hypothesis was wrong. Why? Well, the natural world is complex—it takes a lot of experimenting to figure out how it works—and the more explanations you test, the closer you get to figuring out the truth. For scientists, disproving a hypothesis still means they gained important information, and they can use that information to make their next hypothesis even better. In a science fair setting, judges can be just as impressed by projects that start out with a faulty hypothesis; what matters more is whether you understood your science fair project, had a well-controlled experiment, and have ideas about what you would do next to improve your project if you had more time

Hypothesis Checklist

What are Independent and Dependent Variables?

Question: What's a variable?

Answer: A variable is an object, event, idea, feeling, time period, or any other type of category you are trying to measure. There are two types of variables-independent and dependent.

Question: What's an independent variable?

Answer: An independent variable is exactly what it sounds like. It is a variable that stands alone and isn't changed by the other variables you are trying to measure. For example, someone's age might be an independent variable. Other factors (such as what they eat, how much they go to school, how much television they watch) aren't going to change a person's age. In fact, when you are looking for some kind of relationship between variables you are trying to see if the independent variable causes some kind of change in the other variables, or dependent variables.

Question: What's a dependent variable?

Answer: Just like an independent variable, a dependent variable is exactly what it sounds like. It is something that depends on other factors. For example, a test score could be a dependent variable because it could change depending on several factors such as how much you studied, how much sleep you got the night before you took the test, or even how hungry you were when you took it. Usually when you are looking for a relationship between two things you are trying to find out what makes the dependent variable change the way it does.

Many people have trouble remembering which is the independent variable and which is the dependent variable. An easy way to remember is to insert the names of the two variables you are using in this sentence in they way that makes the most sense. Then you can figure out which is the independent variable and which is the dependent variable:

(Independent variable) causes a change in (Dependent Variable) and it isn't possible that (Dependent Variable) could cause a change in (Independent Variable).

For example:

(Time Spent Studying) causes a change in (Test Score) and it isn't possible that (Test Score) could cause a change in (Time Spent Studying).

We see that "Time Spent Studying" must be the independent variable and "Test Score" must be the dependent variable because the sentence doesn't make sense the other way around.

Independent and Dependent Variable Example

• In a study to determine whether how long a student sleeps affects test scores, the independent variable is length of time spent sleeping while the dependent variable is the test score.

• You want to compare brands of paper towels, to see which holds the most liquid. The independent variable in your experiment would be the brand of paper towel. The dependent variable would be the amount of liquid absorbed by a paper towel.

• In an experiment to determine how far people can see into the infrared part of the spectrum, the wavelength of light is the independent variable and whether the light is observed (the response) is the dependent variable.

• If you want to know whether caffeine affects your appetite, the presence/absence of amount of caffeine would be the independent variable. How hungry you are would be the dependent variable.

• You want to determine whether a chemical is essential for rat nutrition, so you design an experiment. The presence/absence of the chemical is the independent variable. The health of the rat (whether it lives and can reproduce) is the dependent variable. If you determine the substance is necessary for proper nutrition, a follow-up experiment would be to determine how much of the chemical is needed. Here, the amount of chemical would be the independent variable and the rat health would be the dependent variable.

Summary

The Scientific Method

The Scientific Method is an organized way that helps scientists (or anyone!) answer a question or begin to solve a problem. There are usually six parts to it.

1. Purpose/Question – What do you want to learn? An example would be, “What doorknob in school has the most germs ?” or “Do girls have faster reflexes than boys?” or “Does the color of a light bulb affect the growth of grass seeds?”

2. Research – Find out as much as you can. Look for information in books, on the internet, and by talking with teachers to get the most information you can before you start experimenting.

3. Hypothesis – After doing your research, try to predict the answer to the problem. Another term for hypothesis is ‘educated guess’. This is usually stated like ” If I…(do something) then…(this will occur)”

4. An example would be, “If I grow grass seeds under green light bulbs, then they will grow faster than plants growing under red light bulbs.”

5. Experiment – The fun part! Design a test or procedure to find out if your hypothesis is correct. In our example, you would set up grass seeds under a green light bulb and seeds under a red light and observe each for a couple of weeks. You would also set up grass seeds under regular white light so that you can compare it with the others. If you are doing this for a science fair, you will probably have to write down exactly what you did for your experiment step by step.

6. Analysis – Record what happened during the experiment. Also known as ‘data’.

7. Conclusion – Review the data and check to see if your hypothesis was correct. If the grass under the green light bulb grew faster, then you proved your hypothesis, if not, your hypothesis was wrong. It is not “bad” if your hypothesis was wrong, because you still discovered something!

A few other terms you may need to know:

• Independent Variable

• This is the part of your experiment that you will test (vary) to answer your hypothesis. In the example above, the independent variable would be the different colors of the light bulbs.

• Dependent Variable

• This is what occurs in response to the changing independent variable. In our example the Dependent Variable is how much the grass seeds grow.

• Control

• The control should be the part of the experiment where you do not include the Independent Variable. In our example, grass seed that is growing under the white (uncolored) bulb would be your control. The control lets you compare your results in the experiment.