Your Experiment
Science explains how nature works. Your task for the Science Fair is to question, research, experiment, and report your discoveries. Read and follow these directions. After each section, I included an example that I copied from the internet. You may use the internet, too; however do not copy from any published material. Everything you print on your Science Fair display MUST be written in your own words.
The topic for your experiment is up to you (with a few exceptions). Look at books, on the internet, or make up something on your own. Do not do an experiment that involves dangerous materials that may harm you. If you use an animal, do not harm the animal. Also, make sure that you have the equipment needed to measure your results. The school has a lot of equipment and supplies that you may use, but check first.
Question (or Problem)
Start your experiment with a question about something you have observed and you wonder what would happen if you change something. Make sure that you can easily measure the results of your experiment.
Example:
Problem
How does the acid content of different fruits and vegetables (apples, potatoes, limes and lemons) affect the electricity (volts) produced as read with a voltmeter?
Research
The next step is to write about the science behind your question. Do not write about your experiment. Write about the science that is working in your experiment. Start with what you will be measuring to know what to write about. If you are going to measure speed, then first define speed and then write about the biggest factor that will affect speed – friction. If you are going to measure plant growth, then research how plants grow. In the example, they made a potato battery with different fruits and vegetables and measured electricity (volts) so they researched how a battery works.
Read the following example. Notice that they wrote in third person (they did not use the word I). They also wrote facts, not opinion. This example is long, but your research should be 3 to 5 paragraphs.
Example:
Background Research
The first battery was created in 1799 by Alessandro Volta. Today batteries provide the power for an amazing variety of devices including everything from flashlights to robots, computers, satellites and cars. Inventors and researchers continue to improve the battery, designing batteries that last longer and that are friendlier to our environment.
Batteries generate electricity through a chemical reaction between two different electrodes and one electrolyte. An electrode is a conductor through which electricity enters or leaves an object, substance, or region and an electrolyte is a liquid or gel that contains ions and can be decomposed by electrolysis.
A battery produces an electric current when its terminals are connected to each other to form a circuit. All batteries contain two electrodes and an electrolyte, which produces the chemical reaction through the electrodes resulting in a current. In "dry" batteries, like those used to power small toys (AA, AAA batteries for example) the electrolyte is a paste of powdered chemicals. "Wet" batteries, like those in cars, contain a liquid electrolyte. A battery’s voltage depends on the metals that are used in its electrodes.
In a standard battery, there is a strong metal case which usually consists of powdered zinc and a form of magnesium oxide, both mixed with an alkaline electrolyte. The electrolyte causes a chemical reaction in which the zinc becomes zinc oxide and the magnesium oxide gains electrons.
All batteries have a positive and negative terminal. Electric current is a flow of atomic particles called electrons. Certain materials, called conductors, allow electrons to flow through them. Most metals (copper and iron as examples) are good conductors of electricity. Electrons will flow from the negative electrode of a battery, through a conductor, towards the positive electrode of a battery. Volts(voltage) is a measure of the force moving the electrons. Use of Copper and Zinc as the electrodes, and Sulfuric acid (the liquid in a fruit or vegetable) as the electrolyte is a proven method for this process.
The components of a fruit or vegetable that affect the amount of electricity produced is the liquid in the fruit or vegetable itself. The liquid is composed of sulfuric acid, water and a various other liquids. Sulfuric acid is the only thing that the fruit produces or is used to make a battery work.
Hypothesis
A hypothesis is an educated guess about the outcome of your experiment. Your hypothesis should be written as an if, then, because statement. It is a very long sentence. If you do something, then this will happen, because your experiment should follow the science you researched. What you write after the word because is very important because this shows that you understand how things work based on the research you just did.
The results of your experiment should prove that your hypothesis is correct, but this is not always necessary. If your results do not support your hypothesis, you need to examine your work. Did you measure correctly? Was temperature and/or time a factor that you did not consider, but changed the results you wanted? For instance, if you are looking at plant growth and you saw no change after one week, would you see results after four or five weeks? If you bounced a ball outside in the winter, would the results be different than if you bounced the same ball in the summer?
Write your hypothesis based on the scientific research you did. Use an if, then, because statement in a long sentence. Explain how your experiment supported (or why your experiment did not support) your hypothesis in your conclusion.
Example:
Hypothesis
If the electrolyte source is changed (potato, apple, lime, lemon), then the production of energy (measured in volts) using a lemon will produce the highest voltage because the acid content in the fruit or vegetable will produce electricity when in contact with the electrodes (both zinc and copper).
Variables
List the variables in your experiment. A variable is something that can change the outcome of your experiment. Common variables include temperature, time, and material used. In an experiment, it is very important to change only one variable. The independent variable is the variable that is changed. The dependent variable is the result of the experiment that you will measure. All the other variables that you do not change are called constants. For your display, list 3-5 constants.
Example:
Variables
• Independent Variable: The electrolyte source (potato, apple, lime, or lemon)
• Dependent Variable: The voltage
• Constant:
o Same person doing the testing
o Use of same voltmeter
o Same leads, wires
o Conduct experiments in same location
o Same fruit or vegetable
o Same copper penny and same zinc nail.
Materials
List the materials used like a recipe.
Example:
Materials
• Digital Voltmeter that reads tenths of a digit
• 2 potatoes
• 2 lemons
• 2 apples
• 2 limes
• 6 pennies
• 6 zinc nails
• 2 metal leads
Procedure
Write your procedure with clear steps so anyone can repeat the experiment. Remember, a good scientist wants people to try their experiment and get the same result as they did, so write all the steps necessary in your experiment.
Example:
Experimental Procedures
1. Hook up one single fruit or vegetable with one copper penny, inserting it one half inch into the fruit or vegetable.
2. Stick the zinc nail one inch into the other side of the fruit or vegetable.
3. Test the voltage by pressing the metal leads on the copper penny and zinc nail.
4. Read the voltage and write results in science notebook.
5. Wipe off the metal leads for next fruit or vegetable.
6. Connect the other fruits and vegetables the using the stated method above (steps 1-5), testing and writing down results.
7. Repeat steps one through six (three times).
8. Record and compile all results in a graph.
Record Your Results
Make a table to carefully record the results of your experiment. You need to prove that you repeated your experiment three times, so make three tables. Your tables must have a title and be clearly labeled to show what is being measured (don’t forget to include the unit of measurement being used – inches, seconds, etc.)
Example:
Plant Growth With Different Amounts of Light
Time / A Plants (12 hours light) / B Plants (8 hours light) / C Plants: (4 hours light)Day / Height (cm) / Leaves / Height (cm) / Leaves / Height (cm) / Leaves
11 / 1.0 / 1 / 1.0 / 1 / 1.0 / 1
12 / 1.5 / 2 / 1.3 / 1 / 1.1 / 1
13 / 1.9 / 2 / 1.4 / 1 / 1.2 / 2
14 / 2.1 / 2 / 1.6 / 2 / 1.3 / 2
15 / 2.3 / 2 / 1.7 / 2 / 1.4 / 2
16 / 2.5 / 3 / 1.9 / 2 / 1.6 / 2
17 / 2.7 / 3 / 2.1 / 2 / 1.7 / 3
18 / 3.0 / 3 / 2.3 / 2 / 1.8 / 3
19 / 3.3 / 4 / 2.5 / 2 / 2.0 / 3
20 / 3.7 / 4 / 2.8 / 3 / 2.2 / 3
21 / 4.0 / 4 / 3.1 / 3 / 2.4 / 3
22 / 4.4 / 5 / 3.4 / 3 / 2.6 / 3
23 / 4.9 / 5 / 3.7 / 3 / 2.8 / 4
24 / 5.3 / 6 / 4.1 / 4 / 3.1 / 4
25 / 5.9 / 7 / 4.5 / 4 / 3.4 / 4
26 / 6.5 / 7 / 4.9 / 4 / 3.7 / 4
27 / 7.1 / 8 / 5.4 / 5 / 4.0 / 5
28 / 7.8 / 9 / 6.0 / 5 / 4.4 / 5
29 / 8.6 / 10 / 6.6 / 6 / 4.8 / 5
30 / 9.5 / 11 / 7.2 / 6 / 5.2 / 5
31 / 10.4 / 12 / 8.0 / 7 / 5.7 / 6
32 / 11.5 / 14 / 8.7 / 7 / 6.2 / 6
33 / 12.6 / 15 / 9.6 / 8 / 6.7 / 6
Using the results on your table, make a graph. You may average the results from your three tables to make one graph, but add that to your title – Average Tomato Plant Height. While a graph is reporting the same data, it is easier to read and gives a better picture of your results. Bar graphs are good when reporting the final result of an experiment. Line graphs are best when reporting results over time. The following example shows a line graph of results over time. Notice that the graph has a title and the sides are well labeled including the unit of measurement used (centimeters).
Example:
Conclusion
A conclusion is a total explanation of your experiment. Read over your research and show how you used it when making your hypothesis. Write how you proved your hypothesis in your experiment by stating facts from your results (the ball bounced 3 inches higher on the wood floor than on the carpet floor).
Your conclusion must be written in paragraph form. You may write in first person (using the word I or we), but keep to facts. Do not write about how much fun you had or that you learned a lot.
Example:
This experiment confirmed our hypothesis that yeast is alive. When something is alive, it can grow, use energy, reproduce, maintain homeostasis, and respond to its environment. Yeast does not appear to be alive because it does not visibly respond to its environment. In this experiment, we observed whether or not yeast undergoes metabolism by introducing yeast into two different environments: one without a readily available source of energy, and one with readily available energy (in the form of table sugar, or sucrose).
When the yeast was in a low-energy (no sugar) environment, no metabolism took place. When the yeast was placed in a sugar-water solution, it underwent anaerobic fermentation, turning the sucrose into ethanol and CO2gas, which we were able to observe by collecting it in a balloon above the test tube.
Thus, we have seen two pieces of evidence that yeast is alive: first, it uses energy by metabolizing sugar; second, it responds differently in different environments, doing nothing when it is in plain water and fermenting when it is in a sugar and water solution.
Your Display Board
Use the following picture of a display board to know how and where to put the steps in your experiment. You may write by hand, but using the computer makes a neater display and reports can be easily changed. When drawing by hand, always use a ruler to make a straight line.