Introduction: (Initial Observation)
Cranes with electromagnetic lift are also known as electromagnetic cranes. Such cranes are used widely in lifting and moving scrap metals. Even in production line of many products, electromagnetic lifts are used to lift and move metal objects. Electromagnets have special simplicity and many advantages to other lifting tools. They are faster and easier to work with.
In this project we will make a working model of an electromagnetic lift and electromagnetic crane.
Some of the benefits of this project are:
- Gives us an understanding of electromagnetism and its application.
- Help us learn mechanics and the application of levers, pivots, structures, etc.
- We experiment designing and constructing
- We learn manipulating materials and equipment effectively.
Find out about magnets, electromagnets and their applications (uses) in different machines and equipments. Read books, magazines or ask professionals who might know in order to learn about the factors affecting the strength of electromagnets.
Keep track of where you got your information from. The information you gather will form your background information.
Following are samples of information you may find:
History of Electromagnet:
Then in 1820, the Danish physicist Hans Christian Oersted reported that an electrical current passing through a wire deflected a nearby compass needle. His publication immediately set physicists to work on the relationship between electricity and magnetism. Directly after this announcement, the German scientist Johann Schweigger constructed his “multiplier,” or multi-turn coil, which greatly increased the magnetic power of an electrical circuit. Schweigger’s multiplier became the first accurate electrical measuring device–the galvanometer–and remains the basis for modern voltmeters and ammeters. About four years later, William Sturgeon in England invented the electromagnet, a horseshoe-shaped piece of iron wrapped with a loosely wound coil of several turns; the electromagnet became magnetized when a current passed through the coil, and de-magnetized when the current ceased. Sturgeon’s electromagnet, which could be regulated by closing and opening the circuit, converted electrical energy into useful and controllable mechanical work. The galvanometer and electromagnet soon became staples of the electrical laboratory and lecture hall.
An electromagnetic crane is based on the fundamentals of electromagnetism and shows a real life application of electromagnets.
Electromagnet: A magnet that is produced when a current carrying wire is wrapped several times around a metal object.
Work: The force required to move an object over a vertical distance.
Force: Something that can change the motion of an object. Think of it as a push or pull.
Magnetic Field: The area around a magnet where a magnetic force can be detected or felt. The Field is strongest around the North and South poles of the magnet.
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 electromagnets and factors that affect their magnetic force.
The final goal of this project is to build the crane that will be able to lift the heaviest possible object.
Two possible questions that can be studied for the strength of electromagnet are:
- How does the number of wire loops in the coil affect the strength of the electromagnet? (This will be the main question for this project. Identifying variables and hypothesis below are both based on this question)
- How does the thickness of the wire used in the coil affect the strength of electromagnet? (This requires having insulated wires with same length and different thickness)
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.
The independent variable (also known as manipulated variable) is the number of loops of wire in the coil of an electromagnet.
The dependent variable (also known as responding variable) is the strength of the electromagnet. This can be measured and expressed by the mass or number of certain size metal pieces the electromagnet can lift.
Constants are the electricity source and voltage, the wire diameter, the core size and type.
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. Following is a sample hypothesis:
As the number of wire loops wound on a coil increases, the strength of magnet will increase too. My hypothesis is based on my common sense and the electromagnets I have seen so far.
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.”
Introduction: In this experiment you will make three identical electromagnets with 3 different loop counts on their coils and then compare their strengths.
- 3 – 3″ long bolts with nuts
- about 100 feet magnet wire or any insulated solid copper wire size gauge 22
- 1 – 6-volt battery known as lantern battery.
1. Wrap some masking tape or paper on the bolts where you want to wind the wire.
2. Number the bolts from 1 to 3
3. Leave about 2 feet from the beginning of the wire and start winding 100 turns of wire on the bolt number 1, then leave another 2 feet and cut the wire.
4. Wrap some tape on the coil so it does not unwind. Optionally twist the two hanging pieces together to make them more manageable.
If you don’t have access to 3″ bolts, you may use a large nail instead.
5. Remove insulation from both ends of the wire so they will be ready for connection to the battery.
6. Repeat the steps 3 to five with the two remaining bolts; however, wind 200 turns of wire on bolt number 2 and 300 turns of wire on bolt number 3.
7. Get an assistant to help you in the testing step. For each of the three electromagnets you have made, your assistant must connect the two ends of the wire to the poles of a 6 volt battery while you use the electromagnet to lift some small nails. Count or weigh the number of small nails and record that in your data table.
8. After testing the electromagnets 1, 2 and 3, go back and repeat your tests (at the same order) two more times.
9. Calculate the average weight of nails or the average number of nails each electromagnet could lift.
Warning: Do not keep the electromagnets connected to the battery for a long time. This can cause heating up the wires and discharging the battery. Limit each test to about 10 seconds.
Your data table may look like this:
|Electromagnet||Loop count||Strength test 1||Strength test 2||Strength test 3||Average|
The strength is the mass of small nails (in grams) each electromagnet can lift. If you don’t have access to a small scale, the strength will be expressed as the number of small nails each electromagnet can lift.
The strongest electromagnet you have made may be hanged on a wooden crane to form the electromagnetic crane described below.
Activity: Make an electromagnetic crane
Click Here to see a simple, step by step procedure for constructing an electromagnetic crane.
The exact dimensions of each of the parts will depend upon the material available to you
and the specific design that you prepare. The components which make up the crane are shown in the following sketches. Yours can be different based on the material you have access to. Try to use your own ideas and make changes as needed.
Points to consider
- The angle of the jib can be varied by turning the pulley and varying the length of cord wound on the pulley. Similarly, the height of the magnet can be varied by turning the second pulley. (Jib=The arm of a mechanical crane)
- The crane can be rotated by turning the tower on the base.
- Experiment lifting different objects, varying the load for fixed positions of the jib. This would lead to an observation that light loads can be lifted with the jib almost horizontal while to lift heavy loads the jib must be getting closer to the vertical position.
- You may observe that to lift heavier loads a stronger magnet is required which can lead on to an electric circuits project to investigate the relationship between voltage, current, and resistance, and also energy and power for your future projects.
Materials and Equipment:
Materials needed are as follows:
1. Wood indifferent shapes and sizes depending on your design and availability.
4. Bolts and nuts
5. Large nail
6. Hinge and other metal parts (From hardware store)
7. Thermostat wire (Insulated Solid wire #24, about 50 feet)
8. Other insulated solid wires with different thickness for test only (15 feet of each)
9. Knife switch, any other simple switch (optional)
10. 6 Volt battery (Known as lantern battery)
11. Empty spool
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 for this project, however if you do any calculations, you must write them in your reports.
Among the calculations that you might do is to see the lift power of your electromagnet for two different battery voltages (1.5 volts and 3 volts) and then use these numbers to calculate how much will the lift power be with a 6 volts battery. Similar calculations can be done for the number of wire loops in your electromagnet.
Summery 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.
What is an ELECTROMAGNET? A magnet that is produced when a wire carrying electricity is wrapped several times around a metal object such as nail.
What is a FORCE? It is something that can change the motion of an object.
What is WORK? It is the force required to move an object over a vertical, or up and down distance.
What is a MAGNETIC FIELD? The area around a magnet where a magnetic force can be detected or felt. The Field is strongest around the North and South poles of the magnet.
Where are electromagnets used?
Electromagnets are used in many things like telephones, televisions, radios, and microphones.
How an Electromagnet Works?
An ELECTROMAGNET is a magnet that is produced when a wire carrying electricity is wrapped around a METAL surface. All wires carrying electricity have a MAGNETIC FIELD around them, but it is very weak. By wrapping the wire around the METAL surface, the MAGNETIC FIELD is concentrated in one area and is stronger.
How can an Electromagnet do work?
In order for work to be done, an object must be moved over a vertical, or up and down distance. An electromagnet can pick up metal objects using a magnetic FORCE. This force can be used to do WORK.
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.
Visit your local library and find books or articles about electromagnets and their applications. You may also find books about cranes. Review such books for additional information that you may need. Include the books and articles that you review in your bibliography or references.