TESTING WHETHER THE TEMPERATURE OF A MAGNET WILL AFFECT HOW FAR ITS MAGNETIC FIELD IS Kenan Balkas Cary Academy ABSTRACT The purpose of this experiment is about testing to see what the strengths will be of different types of magnets affected by different temperatures. It was hypothesized that if the magnets were overheated, then the various magnets strength would go down. Also it was hypothesized that if the magnets were cooled down to a low temperature, nothing would happen. To do the experiment, the various types of magnets were be heated up with a hot plate, cooled down in a bucket of ice, and left in the open to get the magnets original temperature. After that was done, each magnet would be slowly pushed towards a small nail until the nail got pulled toward the magnet with the force of the magnet s magnetic field. When this was completed, the length between nail and the original place the magnet was in when it pulled the nail toward was recorded. For each measurement there were three trials. What was commonly found in all of experiment, was that the more heated the magnet was the less magnetic field strength it had. In some cases, like with the neodymium magnet, the temperature went up when it was heated to the highest in the experiment. In some cases, when the magnet was cooled down, the magnet field strength stayed the same. In other cases the magnet field strength went up or down. INTRODUCTION The purpose of this experiment was to see if a magnet is heated up to 75 or 125 degrees Celsius will affect how strong it is. Also the purpose of this experiment was to see if the magnet is cooled down to 0 degrees Celsius will it affect its strength.
There were many things observed about the magnets in this experiment. The neodymium magnet had a shiny silver color and was grey on its inside. The magnets were in a cube-shape. They were very brittle so the magnets would break or parts would bulk out depending on how far out they are smashed into each other from. The Neodymium magnets are extremely hard to pull away from each other because their magnetic fields are so strong. The Neodymium magnets are 1.2 Cm all around. Two of the Neodymium magnets could only attract if they were 12 Cm or less than that away from each other. The magnets weigh 15.3 grams. The large ring magnet s shape looks like a doughnut. The large ring magnet was black. When the surface of the magnet is touched black dust comes off. The whole in the middle of the large ring magnet is 2.2 Cm across and the magnet itself is 4.5 Cm across. For two large ring magnets to attract, it takes 7.5 or fewer Cm of space in-between them. The hematite magnet is shiny dark grey color. When the magnets are attracted together from far distances they won t break. The hematite magnet is in all sorts of shapes and has all round edges. The magnet also feels cold to the hand and is very smooth. The average weight between four hematite magnets is 17.4 grams. A hematite magnet is 2.05 Cm across. There needs to be 4 or less Cm of space between two hematite magnets for them to attract. A bar magnet is painted red everywhere but the bottom of it. The North and South Poles are marked on the magnet. The magnet is very smooth everywhere but the grey bottom of the magnet. The bar magnet weighs 8.6 pounds and is three meters across. If two bar magnets are to attract they will need to be at most 1.5 Cm away from each other. A magnetic field is the space around the magnet that has magnetic force flowing out. A magnet has a North and South Pole. The place that points in the South is called the south part of the magnet and the place that points towards North is called the North part of the magnet. The act of repulsion between magnets is created when same poles of the magnets are pointed towards each other. The act of attraction between two magnets is created when the opposite poles of the magnets are pointing towards each other. When certain pieces of metal such as iron are un-magnetized the pieces will not purposely point North-South. When pieces of iron are slightly magnetized by a magnet
they will try to point North-South but they will not point completely point North-South. When pieces of iron are strongly magnetized by a magnet they will point completely North-South. This is how magnets magnetize certain metals. A Neodymium magnet is a rare-earth magnet. It is a permanent magnet meaning that because of the material that it is made from, the material will create the magnetic properties instead of a metal getting magnetic properties transferred to it by another magnet. A neodymium magnet is made from an alloy of neodymium, boron, and iron to create the Nd₂Fe₁₄B tetragonal crystalline structure. The magnet was created in 1982 by General Motors and Sumitomo Special Metals. The grams of force for a 36N magnet are 6474.124 grams of force. A magnet is any material that attracts certain types of metal. If two magnets are close together, they will both exert magnetic force. Magnetic force is created from spinning electric charges in the magnet. The magnetic force can either push or pull the two magnets from each other. Magnetic force is always present when the two magnets are within range of each other. A magnetic field can exist in the places in which magnetic forces can act. Magnetic field lines are created by lines coming from the North Pole of the magnet down to the South Pole of the magnet and vice versa. The closer together the magnetic field lines are, the stronger the magnetic field is. Whether a material is magnetic depends on its atoms. The electrons that make up a magnetic field are created by negatively charged particles of atoms. As one of those electrons moves around, it creates a magnetic field. Then the particle of the atoms will have a North and South Pole. Most materials are not magnetic because the magnetic fields that their atoms make cancel each other out. But in materials like iron, nickel, and cobalt groups of atoms are in areas called domains. When the atom's north and South Pole line up with each other in the domains they will create a magnetic field. It could be thought that domains are tiny magnets of different sizes inside of an object. The setting of where the domains are can affect whether the object is magnetic or not. If the domains in an object are randomly placed then they will cancel each other out, making the object have no magnetic properties. If most of the domains inside an object are aligned, the magnetic fields of the individual domains will combine to the whole object magnetic.
There are a couple different ways a magnet could be demagnetized. If a magnet is hit with something too hard it may move the domains which would dis-align them. Putting a magnet in a strong magnetic field that is opposite to its own may also move the domains causing the same affect. Heating up magnets to high temperatures could shake the atoms inside of the magnet which could interfere with the domains. It is possible to create a magnet out of iron, nickel, or cobalt. For this to work, the domains of the magnet would have to line up. An iron nail could be magnetized if one pole of a magnet is rubbed onto the nail. When this happens the poles of the domains are getting attracted to the one end of the magnet, flipping all of the domains North and South Poles so that the domain s and the magnet s poles would be opposite of each other, making them attract to each other. This would align the domains of the magnet. The more domains that are aligned, the more the object is magnetized. The Physicist Michael W. Bednarz believes that when a magnet is supplied with thermal energy (heat) it will send the tiny electrons spinning inside of the magnet. The electrons inside of the magnet will dis-align meaning that they will point opposite of the electrons next to them. This will also cause the domain walls of the magnet to slide around. When the electrons of a magnet are dis-aligned it will cause the magnet to be less magnetized. Therefore he thinks when it comes to heating up magnets it will weaken its magnetic forces. Based on the information given, it was hypothesized that the magnetic properties of a magnet will be affected by changes in temperature of the magnet. A magnet will be affected if it is heated up or maybe cooled down. When the magnet is heated up, the thermal energy will send the electrons inside of the domains spinning causing the domains to point in different directions which would cause the magnet to less magnetic. If a magnet is cooled down there might not be any affect. Overall, the temperature of the magnet is likely to mess around with the magnet s properties.
MATERIALS AND METHOD Hot plate Ice Water Bucket Neodymium, large ring, hematite, and a bar magnet Small metal block Thin metal plate Meter stick Tape Temperature measurer The control of this experiment was 0 degrees Celsius. The independent variable was the heat of the magnets and the dependent variable was how strong (meaning how far the magnetic field stretched) the magnets were after their temperature was changed. The constants in the experiment were the hot plate, the bucket of ice, and the nail. First a small nail was put out of the magnet's range and then slowly pushed forward and it would be measured how far away the nail was from the magnet when it got pulled towards the magnet, and then that procedure would be repeated at three different temperatures; 0, 55, and 95 degrees Celsius with four different types of magnets (neodymium, bar, large ring, and hematite magnets). The experiment would be repeated three times and the results would be recorded. RESULTS AND DISCUSSION
Magnetic field Strength (cm) Magnetic Field Strength (cm) 3.5 3 2.5 2 1.5 1 0.5 0 0 20 40 60 80 100 Temperature of Neodymium Magnet (Celsius) Figure 1: Neodymium Magnet 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 0 20 40 60 80 100 Temperature of Bar Magnet (Celsius) Figure 2: Bar Magnet
Strength of Magnet (cm) Strength of Magnet (cm) 3 2.5 2 1.5 1 0.5 0 0 20 40 60 80 100 Temperature of Large Ring Magnet (Celsius) Figure 3: Large Ring Magnet 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 0 20 40 60 80 100 Temperature of Hematite Magnet (Celsius) Figure 4: Hematite Magnet Figure 1: When the Neodymium magnet was heated up the 55 degrees Celsius, it reached its worst strength of only being able to pull a small nail from 2 Cm away. When the Neodymium magnet was cooled down to 0 degrees, kept in room temperature, and heated up to 95 degrees, all those temperatures made the Neodymium magnet s
strongest strength being able to pull a nail from 3 Cm away. The relationship between the dependent and the independent variable was inverse. When the magnet was heated up to 95 degrees Celsius, the magnet looked like it was shimmering. Figure 2: The bar magnet reached its strongest strength (1.6 Cm) by it being cooled down to 0 degrees Celsius. It reached its lowest amount of strength (1.5 Cm) by it being heated up to 95 degrees Celsius. The relationship between the dependent and the independent variables was inverse. When the bar magnet was emerged into a bucket of ice, flakes of the red paint came off. Figure 3: The large ring magnet reached its strongest strength (2.5 Cm) at room temperature. It reached its lowest amount of strength (0.5 Cm) by it being cooled down to 0 degrees Celsius. The relationship between the dependent and the independent variables was direct and inverse. When the large ring magnet stuck to the nail when it was heated up to 95 degrees Celsius, the nail became slightly magnetized and shrunk. Figure 4: The hematite magnet reached its strongest strength (1.5 Cm) at room temperature. The hematite magnet reached its lowest amount of strength (1.166 Cm) when it was cooled down to 0 degrees Celsius. The relationship between the dependent and the independent variables was direct and inverse. CONCLUSIONS The hypothesis was that changing the temperature of a magnet will affect how far the magnetic field can reach. It was confirmed because, in many cases, when the temperature of the magnet was increased, the magnetic field s length and strength went down. Also depending on the magnet, the magnetic field s length and strength went up or down. It was inferred that in the experiment, mostly, the magnet s magnetic field length went down when heated up more because when a magnet is heated, the thermal energy from the heat could move the electrons inside of a magnet. That could also move the electrons inside the domains, making them unaligned, which would affect the magnet field negatively. A way the experiment could be improved would be to test the magnetic force for each magnet that would be tested. Also it could be improved by testing more different types of magnets. Some future experiments that could be
performed would be to test whether the size of the magnet affects how strong it is, if magnets will still work if they are melted down, or if magnets will magnetize together in a thick liquid like molasses. REFERENCES Hewitt, Paul.Conceptual Physics.Hewitt, Paul G.2006.print. How Magnets Work. N.p., n.d. Web. 26 Jan. 2014. Magnet Force Calculator. N.p., n.d. Web. 28 Jan. 2014. Physics Van. N.p., n.d. Web. 25 Jan. 2014. Wikipedia. Wikimedia Foundation, 31 Dec. 2013. Web. 28 Jan. 2014.