The Effect of Temperature on the Strength of an Electromagnet

Student Picture

Researched by Monica S.


The purpose of this experiment was to determine the effect of different temperatures on the strength of electromagnets.

I became interested in this idea when I was wondering how a doorbell worked.  Someone told me that there were little electromagnets in each doorbell.  I wanted to figure out if doorbells worked better in colder temperatures or warmer temperatures

The information gained from this experiment could benefit people who have businesses containing electromagnets so they know what weather or temperature electromagnets work better in.


My hypothesis was the warmer the electromagnet was, the stronger it would be.

I based my hypothesis on the fact that the colder things are the less energy the molecules have and the warmer the molecules are the more energy they have.


The constants in this study were:
∑ The materials used to build the electromagnets
∑ Brand of the batteries
∑ Same volt batteries
∑ Age of Batteries
∑ Items picked up (staples)

The manipulated variable was the temperature of the electromagnet.

The responding variable was how much mass the electromagnet could pick up.

To measure the responding variable I determined the mass it could lift by counting how many large staples the electromagnet could pick up.

9 volt D cell battery
12 cm iron nail
Pair of latex gloves
1 Petri dish
4 ft
22 gauge magnetic copper wire
16 oz  
Dry ice
500 ml 
Boiled water
1 Stove
1   Box of staples
Pair of wire strippers


1. Make sure you have all your materials
2. Build electromagnet
a.  Use a wire stripper to remove a few centimeters of insulation from each end of the wire
b.    Wrap the wire around the nail tightly 60 times
c.    Make sure there’s enough wire left at the ends to attach to the power supply
e.    Make sure you wrap the wire around the nail in one direction because the direction of the magnetic current depends on the electric current
f.    Attach one end of the wire to the positive terminal of the battery and the other end of the wire to the negative terminal of the battery and see if it picks up any metal object so you can determine if your electromagnet works
3. Place the electromagnet at room temperature without the battery connected to it.  That means only the wire and the nail sit at room temperature when the magnet is all put together. Do the same with all the other temperatures.
a. When at room temperature for five minutes record how many staples the electromagnet picks up.  That determines the strength of the electromagnet.
b. Do this three more times and find the average number of staples the electromagnet picked up. 
     4. Boil 10ml of water using the stove or any other way to boil water.
5.  Place the electromagnet in the boiling water.
c. Take out the electromagnet and immediately conduct test. Then record how many staples the electromagnet picks up.
d. Turn off stove.
     6.  Place the electromagnet at room temperature for ten minutes to make sure that the electromagnet is back to its original room temperature     
      7. Place electromagnet in 16 ounces dry ice.
b. Take out the electromagnet and record how many staples or the electromagnet picked up.
C.     Clean up mess


The original purpose of this experiment was to determine the effect of different temperatures on the strength of electromagnets. 

The results of the experiment were, that the warmer the electromagnet was the stronger it became.  When at room temperature it picked up an average of 98 staples.  Immediately after it was in boiled water it picked up an average of 128 staples.  When frozen in dry ice it only picked up an average of 32 staples. 

See my table and graph


My hypothesis was the warmer the electromagnet was the stronger it will be.

The results indicate that this hypothesis should be accepted because after it was put into boiled water it picked up 127 staples. When it was put in dry ice it only picked up 30 staples.  

Because of the results of this experiment, I wonder if I would have used longer wire wrapped around a longer nail if maybe it would have been stronger because there are more molecules going through the nail and the wire. 

If I were to conduct this project again I would have used more temperatures variations. Maybe if I conducted more trials the results would have been more reliable.


The definition of an electromagnet is a magnet that consists of a core, often made of soft iron that is temporarily magnetized by an electric current in a coil that surrounds it.  It is just simply a coil of wire wrapped around an iron core.  Electromagnets are used in many different things.  They drive electric door bells, buzzers, and relays.  Electromagnets produce magnetic fields needed to make electric motors and generators work.  Powerful industrial electromagnets lift heavy pieces of scrap iron.  Specially designed electromagnets create very strong magnetic fields that guide atomic particles along desired paths in particle accelerators.   In 1825, William Sturgeon showed an iron core strengthens a coil’s magnetic field.

Electricity is a fundamental form of kinetic or potential energy created by the free or controlled movement of charged particles such as electrons, positrons and ions. All matter is made up of atoms.  Atoms are made up of smaller particles.  The three main particles making up an atom are the proton, neutron, and electron.  Electrons spin around the center, or nucleus, of atoms.  The nucleus is made up of neutrons and protons.  Each atom has a specific number of protons, electrons, and neurons.  No matter how many particles an atom has, the number of electrons usually needs to be the same as the number of protons.  If the numbers are the same, the atom is called balanced.  For example, if an atom has six protons it should also have six electrons.  Some kinds of atoms have loosely attached electrons.  An atom that loses electrons has more protons that electrons and is positively charged.  An atom that gains electrons has more negative particles and is negatively charged.  A “charged” atom is called an “ion”. 

    A magnet is an object that can push or pick up materials made of iron, steel, or nickel.  A magnet is made up of the same materials.  Objects that are attracted by magnets have similar properties.  Every magnet has two places

where its strength is concentrated.  Magnets that are free to turn at will come to rest with their poles aligned in a north south direction.  A magnet can be made from a steel object by striking it with a magnet.  Once magnetized a piece of steel can remain magnetized indefinitely. All magnets have both North and South seeking poles.

Magnets are important in every day life.  Magnets actually provide jobs for people who make magnets or people who work with magnets.  If there weren’t electricity there wouldn’t be electromagnets.  Electromagnets are a big part of the world and they also provide many uses.  If there weren’t any electromagnets we wouldn’t have any doorbells.

A definition of temperature is “A measure of the average translational kinetic energy associated with the disordered microscope motion of atoms and molecules.” Temperature is sometimes called thermodynamic temperature.  Temperature is commonly measured in Celsius, Kelvin, or Fahrenheit, which is most commonly used in the United States.   

Room Temperature
Room temperature is considered to be about 22 degrees Celsius or 72 degrees Fahrenheit.  At that temperature while wearing the normal amount of clothing enough heat is able to radiate away from our bodies where skin is exposed.  If the room air were any warmer this radiation would not be enough to keep us at a comfortable temperature.  The opposite would be true if we were wearing little clothing or if we were naked.   With too much skin exposed our bodies would radiate too much heat and we would feel cold.  We would feel completely comfortable when naked only if the room temperature was close to body temperature, 37 degrees Celsius. 

Boiling is the rapid vaporization of liquid, which occurs when liquid is heated to a temperature that its vapor pressure is above that of the surroundings.  Boiling occurs in three forms, which are nucleate, transition, and film boiling.  Nucleate boiling is the most common type of boiling. It is characterized by bubbles, which rise from discrete points on a surface, whose temperature is only a little bit above the liquid’s saturation temperature.  When the surface temperature reaches a maximum value, vapor begins to form faster than liquid can reach the surface.  The heated surface suddenly becomes covered with a vapor layer.  

Dry Ice
Dry ice is solid carbon dioxide.  It refers to the fact that this substance turns to gas without becoming liquid first. Dry ice is used to refrigerate industrial food, medicine, and other materials that would be damaged by ordinary ice.  A block of dry ice has a surface temperature of –109.3 degrees Fahrenheit.  As dry ice “melts” it turns directly into carbon dioxide gas rather than a liquid.  This is called sublimation.  Dry ice is great for refrigeration.  If you want to send something across the country you can pack it in dry ice.  It will still be frozen when it reaches its destination and there will be no messy liquid left over like you would have with normal ice.

    There are lots of different kinds of temperatures.  Temperature is very important.  Dry ice keeps things cold.  Boiling cooks certain foods that we eat.  And room temperature ‘s what many different things are before cooking or freezing them.

Gardner, Robert        Science Projects About Temperature and Heat New Jersey: Enslow
Publishers inc., 1994. p. 15-17

 Ovelette, Robert J.   “Dry Ice” World Book Encyclopedia,  1998.

Parker, Steve        Electricity. United States: DK Publishing, 1992. p. 1-5

Plumb, Harmon H.        “Temperature” World Book Encyclopedia , 1998

Vahala, George        “Electromagnet” World Book Encyclopedia, 1988



I would like to thank the following people for helping make my project possible:
  • My parents for always being there for me and for buying me all the materials
  • My grandparents for also providing me with materials for my project
  • Mr. Newkirk for correcting my papers all the time.
  • Mrs. Helms for helping me in the computer lab when I needed it.

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