Introduction: (Initial Observation)
Conductivity is the ability or power to conduct or transmit heat, electricity, or sound. Since this project is in the electricity section, we are just comparing material for their conductivity of electricity. To make it simple, any place in this project that we use the words conductive or conductivity, we are referring to the electrical properties of an object or material.
Electricity is traveling from power plants to our homes trough electrical cables. So it is obvious that electrical cables are conductive. Electrical wires at home are covered with plastic and we can touch them safely, so plastics are not conductive. A non conductive material is also called insulator.

Human body is conductive and electricity can pass trough our body. Electricity can stop human heart, damage the brain and contaminate the blood. Such damages can kill a person in just a few seconds. So it is important for us to know conductors and insulators. We use insulators to protect our body from contact to electricity. That is why most tools such as screw drivers and pliers have a rubber or plastic handle.
Information Gathering:
Find out about what you want to investigate. Read books, magazines or ask professionals who might know in order to learn about the effect or area of study. Keep track of where you got your information from.
Following web sites can also be used as references:
Question/ Purpose:
Do all objects conduct electricity?
The purpose of this project is to compare different material for conductivity. We want to know what materials are conductors and what are insulators.
Identify Variables:
Initially our only variable is the type of material that we test. If later we find out that other physical properties such as temperature will affect conductivity, we may expand our research with new variables such as temperature.
Hypothesis:
Based on your gathered information, make an educated guess about what types of things affect the system you are working with. Identifying variables is necessary before you can make a hypothesis.
Some sample hypothesis for this project are:
- All metals are conductors and non-metals are insulators.
- All materials in the world are conductive, some more and some less.
- Material with shiny surface are conductive.
Remember that hypothesis are not the fact. They are just what we guess based on our previous information and observations. That is why we do experiments to test our hypothesis.
Experiment Design:
Design an experiment to test each hypothesis. Make a step-by-step list of what you will do to answer each question. This list is called an experimental procedure. For an experiment to give answers you can trust.
Introduction: We need to test various objects and materials for electrical conductivity. Conductivity is usually being tested by a device called Multimeter. As the name shows, multimeter is not just for testing the conductivity and it can measure many other electrical properties such as voltage in an electrical circuit.
Picture shows an Analog Multimeter that can be purchased from electronic stores for about $30.
This multimeter can show voltage, current and resistance. Resistance here means resistance to electrical current. If a substance has no resistance (Or resistance is zero) it means that electricity can easily travel trough this substance, so it is a good conductor. Also if the resistance is very large number or unlimited, it means that electricity can not pass trough this substance, so it is an insulator. Unit of resistance is called Ohm.
Multimeter also has a Continuity Buzzer. It will make sound when you test it with conductive material.

Multimeter is very helpful tool for every student and is good to have it in any home or workshop. You can use a multimeter for your project, but making a device yourself, usually is a better choice for Science Project.
An easy way to test for electrical conductivity without using a multi-meter is to set up a simple circuit.
Procedure (using a conductivity tester):
- Set your multimeter to conductivity tester mode.
- Prepare the object that you need to test their conductivity. Some of the objects and material that may be tested are: Different coins, different rocks, nail, paper clips, pencil and pencil lead, ceramic magnet, water, salt water, wood, and plastic.
- Connect the two leads of the conductivity tester to two spots on the surface of the object about 1 cm apart (about 1/2 inches apart).
- Listen for the sound of beep as an indication of conductivity.
- Record your results in a table like this.
Object Conductive (Yes/No) Dime lime stone Salt water wood wet wood Rubber
Procedure (using an ohm meter):
- Set your multimeter to Ohms mode.
- Prepare the object that you need to test their conductivity. Some of the objects and material that may be tested are: Different coins, different rocks, nail, paper clips, pencil and pencil lead, ceramic magnet, water, salt water, wood, and plastic.
- Connect the two leads of the conductivity tester to two spots on the surface of the object about 1 cm apart (about 1/2 inches apart).
- See the movement of the needle. The more the needle moves the more conductive the object is. For objects that are really good conductors, the needle will move to 0. The resistance for such objects is 0. Objects that are less conductive have a resistance (any number larger than 0). The largest possible resistance is for insulator objects. In this case the needle will not move at all and you write Insulator in your results table.
- Record your results in a table like this.
Object Resistance Dime 0 lime stone Salt water wood wet wood Rubber Insulator
A simple electric circuit can also be used to test the conductivity. It will be used the same as a conductivity tester. The only difference is that instead of beeping, the light bulb will light up.
Simple Electric Circuit:
Make a basic electric circuit including a battery, a light bulb and a switch. Test your circuit by closing the switch and make sure that the light bulb lights up. Now remove the switch and replace it with a pair of insulated long wire (about two feet each).
Remember that you need to remove about one inch of insulators from each end of your wires.
As the following picture shows, you could also keep the switch but leave it in open position. Two long wires act like the electrodes of your test device.

Now let these wires touch each other. The light should turn on. What you have made is a continuity tester or conductivity tester. You can test different objects for conductivity by connecting these wires at the same time to two different spots of that object. Those who turn on the light are conductive and others are not.
In each test, see how bright is your light. More light indicates more electric current, so your object is more conductive.
Materials and Equipment:
Multimeter can be purchased from most electronic stores. For basic electric circuit you will need the following items:
- A mounting board (0.5″ tick wooden piece about 5″ x 7″)
- Socket for miniature light bulb.
- 2.5 volts screw based light bulb
- Battery holder (That holds two AA batteries)
- Three lengths of insulated wire with insulation removed from each end (About 3 feet Thermostat wire. Gage 24)
- Screws to secure the above pieces on a mounting board.
- 2 AA batteries
Above material can be purchased from local hardware stores and electronic stores. If you prefer a kit, Electricity and conductivity Science kit of MiniScience.com includes everything listed above with exception of a multi-meter and batteries.
Results of Experiment (Observation):
Following are some of the material that you can test for conductivity. Record the results in a table similar to this by putting an X in the appropriate cell.
Rocks | ||||
Spoon | ||||
Graphite of a pencil | ||||
Crayon | ||||
Magnet | ||||
Tap Water | ||||
Wood | ||||
Plastic | ||||
Glass | ||||
Aluminum foil |
Some other objects to be tested are Styrofoam pieces, nail, paper clip, cloth, etc.
Note that distilled (pure) water does not conduct electricity, while tap water that containing impurities does.
Calculations:
If you do any calculations, write your calculations in this section of your report.
Summary of Results:
Summarize what happened. This can be in the form of a table of processed numerical data, or graphs. It could also be a written statement of what occurred during experiments.
It is from calculations using recorded data that tables and graphs are made. Studying tables and graphs, we can see trends that tell us how different variables cause our observations. Based on these trends, we can draw conclusions about the system under study. These conclusions help us confirm or deny our original hypothesis. Often, mathematical equations can be made from graphs. These equations allow us to predict how a change will affect the system without the need to do additional experiments. Advanced levels of experimental science rely heavily on graphical and mathematical analysis of data. At this level, science becomes even more interesting and powerful.
Conclusion:
Using the trends in your experimental data and your experimental observations, try to answer your original questions. Is your hypothesis correct? Now is the time to pull together what happened, and assess the experiments you did.
This is a sample:
Copper is the best conductive of electricity followed by gold and aluminum as the second and third best conductive metals.
Related Questions & Answers:
What you have learned may allow you to answer other questions. Many questions are related. Several new questions may have occurred to you while doing experiments. You may now be able to understand or verify things that you discovered when gathering information for the project. Questions lead to more questions, which lead to additional hypothesis that need to be tested.
Some related questions:
1. Which objects conducted electricity? How do you know?
2. How were the conducting materials similar?
3. What appliances need materials that easily conduct electricity?
4. What appliances need materials that do not easily conduct electricity?
5. Sum up in paragraph form why these appliances do or do not conduct electricity easily.
6. Using these vocabulary words: electric current, resistance, conductors, and insulators, sum up in paragraph form how this makes a toaster work.
Additional Information:
Wires made of material other than copper and that are very thin cause higher resistance because it is harder for the current to pass through. The wires become so hot that they either give off light or heat or both. Examples of appliances that do not easily conduct electricity and have a higher resistance are light bulbs, hair dryers, toasters, electric blankets, etc. Appliances that easily conduct electricity are refrigerators, televisions, stereos, etc.
Possible Errors:
If you did not observe anything different than what happened with your control, the variable you changed may not affect the system you are investigating. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. The first thing to check is how you are making your measurements. Is the measurement method questionable or unreliable? Maybe you are reading a scale incorrectly, or maybe the measuring instrument is working erratically.
If you determine that experimental errors are influencing your results, carefully rethink the design of your experiments. Review each step of the procedure to find sources of potential errors. If possible, have a scientist review the procedure with you. Sometimes the designer of an experiment can miss the obvious.
References:
List of References