Science Fair Experiments that get good grades – Experiment #56 - Cool circuits

Are you looking for a really cool science project to do that will get you an awesome grade? There are tons of science fair experiments to choose from if you want to do something interesting. Do you like electricity? How about doing a project on circuits? In this project, I’m going to explain how to do an experiment that tests if the length of a pencil resistor changes the output of a circuit.

 For this project, you can expect the difficulty level to be mild. Although some science fair experiments take weeks, this one should only take you a few days to complete. Most material required will be readily available. The only thing you need to keep in mind is that you should have adult supervision while doing your experimentation, because you are dealing with electricity!  

Introduction

Electricity is extremely important to everything we do. In fact, not one of the many modern amenities that we enjoy today could be in existence without it. The delicate balance among each of the pieces of a circuit from the wires to the batteries to the resistors, along with the entirety of a circuit, allows for the electricity that we know so well to exist.  

For this science project you will assemble all of those pieces in order to build your very own simple electrical circuit. You will use the circuit to learn a bit more about resistors. Some of the things you will consider are: How do we use resistors? Why are resistors so useful to us? How does the size of a resistor change the circuit?  

Science fair experiments always require you to become acquainted with certain terms and concepts. Before you begin the project, you should become familiar the following: insulators and conductors, flow of current, resistors, circuits and electricity. 

By the way, getting a free copy of Easy Steps to Award-Winning Science Fair Projects will help you through your own project.

What you will need for this experiment:

•    #2 pencils

•    an alligator clip set that is insulated

•    9 Volt battery

•    9 Volt connector for the battery

•    a 9 Volt small light bulb

•    a holder that is for small bulbs

•    ruler

•    an automatically run pencil sharpener

•    popsicle stick

•    with help from your parents, you will need a coping saw

Steps for the Experimental Procedure:

 1.    First, you will have to prepare the circuit board. This will be used in testing your resistors. To complete this step, you must have 3 pieces of wire that each have alligator clips on their ends. (You can buy these alligator clip sets from an electronics store.)

2.    Clip one of the alligator clips from one of your wires and attach it to one of the terminals on the battery.

3.    Affix the opposite end of the same wire to the second screw for contact on the bulb holder.

4.    Screw in your light bulb.

5.    Before you can begin your science fair experiments, you have to ensure that your circuit actually works. Carefully, you will need to bring the two empty ends of the alligator clips together. Keep from getting a shock by touching only the plastic insulated sleeves on the clips.  If the light comes on, you are all set to continue to the next part of the experiment.  If not, you will need to go back to the beginning and try again until it works.

6.    Next, you need to create the pencil resistors in order to test your circuit. In this experiment, you will craft several various resistors of varying sizes.  You will do this by cutting pencils into varying lengths and then by sharpening the pencils on both ends.

7.    With your parents help, use the saw to create different length pencils. Make them a nice variety like 4 inches, 5 inches, 8 inches, and so forth.

8.    With your pencils all cut, sharpen both ends of each one using your sharpener.

9.    Keeping track in a results table, you will now have to measure each of your pencils from one tip to the other. You will want to have 2 rows that say: Pencil Length, Light’s Brightness.

10.    Next, you will insert all of your different pencils into the circuit by clipping them onto the lead part of the tip using the alligator clips.  Wood is an insulating material so be sure that you do not clip onto the wood part or your circuit will not work.

11.    Every time you connect a new pencil, check out the light’s brightness. Record your observation. Make up a number scale to explain what brightness you see, like on a scale from one to five, decide how bright each pencil’s bulb is, one being dark and five being light.

12.    You will use the wooden popsicle stick and the extra piece of wire to make up your controls. Using the same technique you used for the pencils, insert the two controls into your circuit and use the same brightness scale to rate each of them.  The wire will make your positive control and the wooden popsicle stick will make your negative control.

 Great science fair experiments always have variations. Something you can do for a variation on the experiment is to try testing the same circuit using different types of materials to determine if they are good insulators or good conductors. Use common household items as your test group. You would be surprised at how tricky they can be to predict! 

To help you with your own project, take a look at some of the links next to this article.

Good luck!