Laboratory Report

Magnetism

Report from laboratory experiments conducted on

11/02/11 as part of PHSC0152 Sec. 02

Sharon Cameron

11/17/11
1. Aim

You will familiarize Yourself with several different kinds of magnets. They will observe the forces of attraction and repulsion between the different poles. I will introduce and we will experiment with the forces of magnetism, electromagnetism

2. Apparatus Magnets, batteries, compasses, suspended magnet, permanent magnet, iron filings, electromagnet, nails, straight wire.

3. Theory

Everything in the universe is made of atoms—they are the building blocks of the universe. Atoms are so small that millions of them would fit on the head of a pin. Atoms are made of even smaller particles.
The center of an atom is called the nucleus. It is made of particles called protons and neutrons. The protons and neutrons are very small, but electrons are much, much smaller. Electrons spin around the nucleus in shells a great distance from the nucleus. If the nucleus were the size of a tennis ball, the atom would be the size of the Empire State Building. Atoms are mostly empty space. If you could see an atom, it would look a little like a tiny center of balls surrounded by giant invisible bubbles (or shells). The electrons would be on the surface of the bubbles, constantly spinning and moving to stay as far away from each other as possible. Electrons are held in their shells by an electrical force. The protons and electrons of an atom are attracted to each other. They both carry an electrical charge. An electrical charge is a force within the particle. Protons have a positive charge (+) and electrons have a negative charge (-).The positive charge of the protons is equal to the negative charge of the electrons. Opposite charges attract each other. When an atom is in balance, it has an equal number of protons and electrons.
The neutrons carry no charge and their number can vary. In most materials, the forces are in balance.
Half of the electrons are spinning in one direction; half are spinning in the other, and they are randomly scattered throughout the materials. Magnets are different. In magnets, most of the electrons at one end are spinning in one direction. Most of the electrons at the other end are spinning in the opposite direction.
This creates an imbalance in the forces between the ends (poles) of a magnet. This creates a magnetic field around a magnet. A magnet is labeled with North (N) and South (S) poles. The magnetic force in a magnet flows from the North pole to the South pole. Like poles of magnets repel each other and opposite poles attract each other. If you try to push the South poles together, they repel each other. Two North poles also repel each other. Turn one magnet around and the North (N) and the South (S) poles are attracted to each other. The magnets come together with a strong force. Just like with protons and electrons, opposite magnetic forces attract. Metals that can be magnetized include iron, nickel, and cobalt.
Steel is made of iron and other metals. The Earth is a magnet with North and South poles, because its core is iron. Scientists believe that the Earth’s poles have reversed several times in the past, but they don’t know why.

(1)
Provide a neat, correct and clear schematic drawing, photo or sketch of the experimental set-up, showing all the interconnections and interrelationships. Include a short textual description that refers to all parts of the schematic drawing. This section should have all the information needed for a reader to duplicate the setup independently.

4. Procedure

MAGNETIC FIELDS .

Materials Needed

1 bar magnet
1 compass

Procedure

1. Place the magnet in the center of the next page.
2. Put the compass near one end of the magnet. Let the needle stop moving. Note the direction of the needle. Lift the compass and draw an arrow where the compass was. The arrow should point in the same direction as the painted end of the compass needle.
[pic]
3. Move the compass toward the middle of the magnet. When the needle settles, note its direction and draw an arrow as before.
4. Repeat this as you move the compass to the other end of the magnet.
5. Now start again from a different place near the end of the magnet. Go from end to end at least 3 times. Explore both above and below the magnet.
6. When you're done, your arrows show you where the magnetic field is.

5. Safety and Precautions
Exercise general lab cautions. Be careful not to accidentally drop the bars.

6. Data

Prepare a table(s) of experimental data. All the pertinent raw data obtained during the experiment are presented in this section. The type of data will vary according to the individual experiment, and can include numbers, sketches, images, photographs, etc. All numerical data should be tabulated carefully. Each table, figure and graph in the report must have a caption or label and a number that is referenced in the written text. Variables tabulated or plotted should be clearly identified by a symbol or name, and units, if any, should be clearly noted. This section should contain only raw information, not results from manipulation of data. If the latter need to be included in the same table as the raw data in the interests of space or presentation style, the raw data should be identified clearly as such.

7. Calculations

Show calculations and graphs. This section describes in textual form how the formulaic manipulation of the data was carried out and gives the equations and procedures used. If more than one equation is used, all equations must carry sequential identifying numbers that can be referenced elsewhere in the text. The final results of the data analysis are reported in this section, using figures, graphs, tables or other convenient forms. Sample calculations and details of calculations and analyses should be placed in an Appendix, and the reader directed to the appropriate section of that Appendix for that information. The end result of the data analysis should be information, usually in the form of tables, charts, graphs or other figures that can be used to d

8. Error
List the possible sources of error. Write down the precision and accuracy of your measuring equipment and the kinds of observational errors you might make.

9. Error Calculations
Calculate the experimental accuracy and percentage error. Recall that the basic equation for error calculations is:

% error = |actual – experimental | x 100% actual

10. Results

Describe the experimental results observed. This section is devoted to your interpretation of the outcome of the experiment or project. The information from the data analysis (Calculations) is examined and explained. You should describe, analyze and explain (not just restate) all your results. This section should answer the question 'what do the data tell me?' Describe any logical projections from the outcome, for instance the need to repeat the experiments or to measure certain variables differently. Assess the quality and accuracy of your procedure. Compare your results with expected behavior, if such a comparison is useful or necessary, and explain any unexpected behavior.

11. Conclusions

Discuss the results, sources of error and whether the error in the experiment is reasonable based on the sources of error. Base all conclusions on your actual results. Explain the meaning of the experiment and the implications of your results. Examine the outcome in the light of the stated objectives. Seek to make conclusions in a broader context in the light of the results.

Appendix A. References (Bibliography)

Using standard bibliographic format (visit or contact the HSSU AT&T Library & Technology Resource Ctr. for availability of accepted style guides and citation formats), cite all the published sources you consulted during the conduct of the experiment and the preparation of your laboratory report. List the author(s), title of paper or book, name of journal, or publisher as appropriate, page number(s) if appropriate and the date. If a source is included in the list of references, it must also be referred to at the appropriate place(s) in the report. You mist also include websites and pages visited and used.

Reference: Basic information included in these guidelines was adapted from the Louisiana Tech University College of Engineering and Science, laboratory report template. www.coes.latech.edu/tutorials/htwalr/coes_laboratory_report_template.doc