Introduction: (Initial Observation)
The discovery of magnetism has had a very important role in human life and modern technology. Magnets are an essential part of electric motors and generators. Without magnets, electric generators could not produce electricity. Things that would disappear if we had no electricity are telephones, lights, electric heat, computers, televisions. The fact that an invisible magnetic force is able to attract or repel certain metals is enough interesting for a science project.
Magnets can be made by placing a magnetic material such as iron or steel, in a strong magnetic field. Permanent and temporary magnets can be made in this manner.
Find out about magnets and magnetism. Click here for some online information. Also read books, magazines or ask professionals who might know in order to learn about making magnets, uses of magnets and factors that may affect the strength of a magnet. Keep track of where you got your information from.
Following are samples of information that you may find.
As magnetic substances are able to retain magnetism for different periods of time that range from a very short period of time to a very long period of time, magnetic substances are used for making magnets. There are some magnetic substances that are good for making temporary magnets, and some for making permanent magnets. Iron and Steel are two of the magnetic substances which can be used to make magnets. Before we proceed to learn how to make magnets, let us first learn about the properties of Iron and Steel .
Properties of Iron and Steel
|Magnetism in iron is strong||Magnetism in steel is weak|
|Magnetism in iron is temporary. Magnetism is retained so as long as iron is in the close vicinity of a magnet.||Magnetism in steel is permanent. Magnetism in steel is retained even after the external magnetic force is removed.|
|Good for making temporary magnets||Good for making permanent magnets|
|Can be magnetized easily||Difficult to magnetize|
Magnets can be made by using several methods. The most commonly used methods are as given below:
Single Touch Method
The single touch method involves the usage of only one magnet and a steel bar. In order for the magnet to be a permanent magnet, a steel bar is used. As shown in Figure (a), bar AB represents the steel bar.
- The bar magnet (with north pole in this figure) is placed at end A if the steel bar, and moved towards end B without lifting the magnet.
- Once it reaches end B of the steel bar, the magnet is lifted and placed at end A and moved towards end B in the same direction as before.
- Steps 1 and 2 are repeated at least 30 times. This method of moving the magnet over the steel bar is referred to as rubbing the steel bar or stroking the steel bar with the magnet. The steel bar should be rubbed with the magnet in the same direction, otherwise the steel bar will not get magnetized.
Fig. (a)Single Touch Method
In this case (Fig. a) while rubbing the steel bar with the North pole from end A to end B, end A of the steel bar becomes the North pole while end B of the steel bar becomes the South pole.
Double Touch Method
Fig (b). Double Touch Method
The double touch method involves the usage of two magnets and a steel bar. In order for the magnet to be a permanent magnet, a steel bar is used. As shown in Figure (b), bar AB represents the steel bar.
- The two bar magnets with opposite poles facing each other are first placed at the center of the steel bar.
2. The bar magnets are then moved towards the ends of the steel bar without lifting the magnets.
3. Once the magnets reach the ends of the steel bar, the magnets are lifted and placed again at the center of the steel bar, and moved towards the ends in the same direction as before.
4. Steps 1 to 3 are repeated at least 30 times.
In this case (Fig. b), rubbing the steel bar using two magnets with opposite poles facing each other as shown in Fig. (b), end A of the steel bar becomes the North pole while end B of the steel bar becomes the South pole.
Note: It must be borne in mind that since steel is very hard to magnetize, it may be required to stroke the steel bar for a long period of time. Iron on the other hand is very easy to magnetize. However, iron loses its magnetism very quickly.
The following equipments are required in order to make an electromagnet:
- Iron object such as iron nail or iron bar
- Insulated copper wire
- 1.5 volts or 3.0 volts battery/cell
- iron paper clips or iron filings
Fig. (c). An Electromagnet
- Take any iron object such as an iron nail.
- Wind an insulated copper wire around the iron nail about 100 times.
- Remove the insulation from about 1 cm (1/2 inch) of each end of the wire.
- Now connect one free end of the wire to the positive terminal of a battery/cell, and the other free end of the insulated wire to the negative end of the battery/cell, as shown in Fig (c).
- Try bringing some iron filings or pins at any end of the iron object that is getting magnetized. What do you think might happen?
Once the circuit is completed by connecting the free ends of the wire to the terminals of the battery/cell, electric current starts flowing through the wire from the positive terminal to the negative terminal. This generates a magnetic field around it and the iron nail gets magnetized. It starts behaving like a magnet so as long as the electric current flows through the wire. At this point of time, if any magnetic substance is brought close to the iron nail, the magnetic substance will get attracted to the iron nail and cling to it so as long as the nail remains magnetized or retains its magnetism. Once the the flow of electric current through the insulated wire is stopped, the pins or iron filings will fall off the nail provided the nail is made of iron. If the nail is made of steel then the nail will retain some magnetism and the pins will not fall off.
Note: Replacing the iron nail with a steel nail will give you a permanent magnet.
Strength of the electromagnet
The strength of an electromagnet can be increased by:
- Increasing the number of turns
- Increasing the voltage of the battery.
- Using iron instead of steel
Circuit: Route laid out with wires which connect circuit components along which the electrical current flows.
Compass: An instrument that is used to find/determine the North-South directions. It is often used for navigational purposes.
Current: Flow of electrons through a wire
Displacement: Change in position in a given direction
Energy: Capacity to do work
Force: Defined as push or pull
Magnetic substances: Substances that get attracted to magnet and can be magnetized
Magnetic field: Area around a magnet.
Magnetite: A natural form of magnet
Poles: The two ends of a magnet that have maximum forces of attraction.
Solar wind: Stream of ionized gases that blows outward from the Sun with varying intensity that depends on the amount of surface activity on the Sun.
Turns: the number of times a wire is wound around an object such as a nail or bar.
Work: Product of force and displacement in the direction of the force
What do you want to find out? Write a statement that describes what you want to do. Use your observations and questions to write the statement.
The purpose of this project is to learn about magnets and how they are made. Specific question that can be studied in this project is:
- How can you make an Iron nail to become a magnet? and which method of making magnet creates a stronger magnet?
When you think you know what variables may be involved, think about ways to change one at a time. If you change more than one at a time, you will not know what variable is causing your observation. Sometimes variables are linked and work together to cause something. At first, try to choose variables that you think act independently of each other.
Depending on the question that you choose to study, you may define different variables or factors that are being studied.
For the main question of this project, this is how you may define variables:
- Independent variable (also known as manipulated variable) is the method of making magnet.
- Dependent variable (also known as responding variable) is the strength of magnet that can be made. The strength can be measured by the amount of iron filings of small nails that the magnet can lift.
If you are doing this as a display project, you may not be required to define variables and to perform multiple experiments.
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. For example if you want to make magnet using electricity, following are some possible hypothesis.
- Making magnet using electricity produces a stronger magnet in compare with magnets that are made by rubbing against another magnet.
- While using electricity to make magnet, more electricity (stronger battery, higher Voltage and Current) can make stronger magnet.
- While using electricity to make magnet, more loops on the coil of wire can create stronger magnets.
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, it must have a “control.” A control is an additional experimental trial or run. It is a separate experiment, done exactly like the others. The only difference is that no experimental variables are changed. A control is a neutral “reference point” for comparison that allows you to see what changing a variable does by comparing it to not changing anything. Dependable controls are sometimes very hard to develop. They can be the hardest part of a project. Without a control you cannot be sure that changing the variable causes your observations. A series of experiments that includes a control is called a “controlled experiment.”
Experiment 1: Making magnets using electricity
In this experiment you will magnetize a few identical nails with different methods as described in the gathering information section. If you are doing a display project, that is all you need to do as your experiment; otherwise you need to compare the strength of magnets made in different methods.
Get some magnet wire (or any other single strand insulated wire) and wrap it around a nail. Connect the two ends of the wire to the battery set. Use some paper clips to see if your nail is magnetized. What you have made is an electromagnet.
Magnet wire is a regular copper wire with a thin coating of an insulating material. You need to remove the coating from both ends of your wire in order to create a good contact with your battery poles (Or battery holder wires). The coating of magnetic wire is a special type of resin that can be removed by scratching with a sharp object or sand paper. You should get a good result if you have wrapped your magnet wire at least 20 times or more around the nail.
Now use a compass or another magnet with marked poles. Test to see which side of the nail is the North Pole and which side is the South Pole of your magnet. Switch the battery poles and see if it affects the North/South Poles of your magnet. You can also change the direction of the wrapping of the wire to see the effect of that on North and South Poles of your electromagnet.
Most nails will become a permanent magnet after such experiment. In other words a strong magnetic field created by the coil and the battery can change a regular steel nail to a permanent magnet .
So remove the coil of wire from around the nail and see if the nail has enough magnetic force to lift a small paper clip or a small needle.
You can try different types of nail and compare the results.
Experiment 2: Make magnet using touching or rubbing method
One of the methods to make a magnet is the touch method or rubbing method. This method is described in the gathering information section (above) in detail. For example you can magnetize a nail or needle by rubbing it with a strong magnet. As a mater of fact, even placing a strong magnet close to a nail for a few seconds can induce some magnetic properties on the nail. For this reason, many nails and other steel objects around you may already have some magnetic properties.
Mark one end of the needle with a marker (optional).
Magnetize the needle by rubbing it with a strong magnet (single touch method) for 1 minute.
To see if your needle is really magnetized, use it to make a compass as described below:
Make a Compass
Insert the needle in a small cork or small piece of Styrofoam.
Fill up a cup with water. It helps if you overfill the water so the water level will be above the edges of the cup.
Float the needle carefully in the center of the water.
Does the needle move and then stay in a specific north/south direction?
Overfilling the cup with water makes the needle stay in the center, otherwise it will move to the side.
Change the direction of needle and then release it again. Does it move back to the north/south direction?
Experiment 3: Comparing methods of making magnet
- Get 5 identical large nails and number them from 1 to 5.
- Use touch method to magnetize the nail number 1 for 1 minute.
- Use a coil of 50 turns wire and a 1.5 volt battery to magnetize the nail number 2 for 1 minute.
- Use a coil of 100 turns wire and a 1.5 volt battery to magnetize the nail number 3 for 1 minute.
- Use a coil of 50 turns wire and a 3 volt battery to magnetize the nail number 4 for 1 minute.
- Do not do anything with the nail number 5 and keep it as control.
- Test all the nails to find out the maximum iron filing that they can lift.Record your results in a table like this:
(weight of iron filings)
|2||1.5V – 50 turns|
|3||1.5V – 100 turns|
|4||3V – 50 turns|
As a 3 volt battery, you may connect two 1.5 volt batteries in series (One behind the other).
4″ common nails or larger may be used for this experiment.
Materials and Equipment:
To make electromagnet you need a 6 volts battery. Hardware stores sell special 6 volts batteries known as lantern battery. You can also connect 4 flashlight batteries using a battery holder to get 6 volts. List of material including optional items is here:
- Battery Holder (for 2 or 4 flashlight batteries of any size)
- Insulated wire (Gage 24, also known as thermostat wire)
- One Iron nail (2″ or 3″) or similar metal rod.
- A strong magnet.
- Some Iron filings, pins or paper clips to test the magnet.
- A small compass to test the magnet poles.
Results of Experiment (Observation):
Experiments are often done in series. A series of experiments can be done by changing one variable a different amount each time. A series of experiments is made up of separate experimental “runs.” During each run you make a measurement of how much the variable affected the system under study. For each run, a different amount of change in the variable is used. This produces a different amount of response in the system. You measure this response, or record data, in a table for this purpose. This is considered “raw data” since it has not been processed or interpreted yet. When raw data gets processed mathematically, for example, it becomes results.
No calculation is required.
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.
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.
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.
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.