Magnetic field is a region of space surrounding a magnetized body in which the resulting magnetic force can be detected. The strength and direction of magnetic forces vary in different parts of such region. Since the strength of magnet is important in all magnet applications, it is important to know the direction and strength of magnetic forces around a magnet. A drawing of a magnetic field is a good representation of such forces.
If you ever wondered how strong are magnetic forces in different areas around a magnet, this is a project for you.
Learning about magnetic field and direction of magnetic forces in a magnetic field will help us to understand the properties of magnets and use it in a more effective and more creative way.
Information Gathering:
Find out about magnets and magnetic fields surrounding each magnet. Read books, magazines or ask professionals who might know in order to learn about possible methods of observing or recording a magnetic field. Keep track of where you got your information from.
Click Here for general information about magnet.
Question/ Purpose:
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.
Following are some of the questions that can be studied in this project.
- How are the magnetic forces distributed around a magnet?
- What are the directions of magnetic forces around a magnet?
Identify Variables:
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.
In a display project you will not need to define any variables; however, it is good to know that the shape, size and other properties of a magnetic field depend on the shape, strength and magnetic orientation of each individual magnet.
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.
In a display project you will not need to suggest a hypothesis; however, anything that you think about the strength and direction of magnetic forces around a magnet before doing your experiment, that is your hypothesis. For example this is a sample hypothesis:
I think the strength of magnetic forces are more in the area between two poles.
Your experiment later will show that the strength of magnetic field between the poles is the lowest possible. So you reject your hypothesis or correct it.
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, 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: Forming and fixing a magnetic field
Introduction: Iron filings in a magnetic field rearrange themselves and get to a new formation that displays the magnetic field. We can use spray glue or clear paint to save such formation.
Material:
- Cardboard 8.5″ x 11″ or larger
- One cow magnet or rod magnet
- Spray adhesive
- Iron filings
Magnets are sold in hardware stores. You will need a rod magnet about 2 to 3 inches long. (A shorter or longer magnet will work as well).
Spray adhesive is sold in office supplies and art supplies stores. If for any reason you cannot find the spray adhesive, you may try clear spray paint instead.
Iron filings may be found at a local craft store. Iron filings are the result of cutting or grinding iron. You may also get some free iron filings from a local iron working shop. Both magnet and iron filings are also available at MiniScience.com and are part of most magnetism related science kits.
Procedure:
- Place the rod magnet on a wooden or glass table, away from any iron piece.
- Place some books, papers or magazines on the sides of the magnet up to the level of magnet.
- Place the cardboard on the top of magnet in a way that magnet will be centered under the cardboard.
- Evenly sprinkle some iron filings all over the cardboard.
- Tap the cardboard a few times forcing the iron powders to relocate and position themselves on the lines of magnetic field.
- When the magnetic field is formed, spray the cardboard with spray adhesive. Be generous in using the adhesive spray. You may want to repeat spraying a few times (about 30 minutes apart) to ensure strong adherence of iron filings to the cardboard. Do not remove the cardboard until the adhesive is fully dried.
- Hold the cardboard from the opposite sides and lift it up away from magnet. On a tray, turn the cardboard on the side and tap it a few times to get ride of any remaining loose iron filings.
- Put your drawing in a frame or a box for your final presentation.
Additional Experiments:
Repeat the above experiment with ring magnet and horse shoe magnet. Report how different are the magnetic fields.
Materials and Equipment:
- Cardboard 8.5″ x 11″ or larger
- One cow magnet or rod magnet
- Spray adhesive
- Iron filings
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.
The result of your experiment is the magnetic field that you print.
Primary projects such as this one (for students in 1st grade up to 4th grade) are display projects. There will be no data table for display projects.
You may also try this as an experimental project:
In an experimental project you may want to study the relation between the size and the strength of magnets. For example you may get three different size magnets and compare them for the amount of nail that they can lift. That will be an experimental project and your data table will show the size of magnets and the amount of nail lifted by each magnet.
Calculations:
No calculation is required for this project.
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.
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.
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:
Visits your local library and find books about magnetism and magnetic field.
Look up a dictionary and an encyclopedia for the terms magnet and magnetic field.
Following are some web resources:
http://www.uccs.edu/~tchriste/courses/PES100/100lectures/magnet.html
http://www.geo.lsa.umich.edu/~crlb/COURSES/117/Lec17/lec17.html
http://www.arnoldmagnetics.com/mtc/pm_manual_chap_1.htm
