Something is a mystery...Is that Chem?
- Sundry Fires In Rain
- Feb 11, 2019
- 8 min read
Updated: Feb 22, 2023
Misty Mystery above
Design an experiment to study one of the factors affecting the strength of an electromagnet.
v Electromagnets are simple devices that mimic the behavior of natural magnets, with one important difference: the ability to change their magnetic field strength because of their electrically generated magnetic fields.
You can choose one among these factors to design the investigation:
Ø Number of turns on the coil of wire around the core.
Ø Strength of the current applied.
Ø The material of the coil.
Ø Temperature
Ø Diameter of the wire (used as a coil)
Your design must contain the following:
Checklist of the contents of your design lab
· Research Question: One question that clearly states your experiment and purpose
· Hypothesis: one statement which shows your prediction of how independent and dependent variables are connected
· One independent variable that you would like to study
· Outline how you would manipulate the independent variable during this investigation.
· Outline how you would measure the dependent variable during this investigation.
· Identify three (3) controlled variables for this investigation. For each controlled variable outline how you would control it.
· Material required: this can be a list of materials that will be used in your experiment.
· Procedure: Clear and step-wise procedure to explain how the experiment will be conducted. This must have at least 8 steps.
· Outline 2 potential safety issues and describe how you would miniseries the risk involved.
· Data collection Table: A table showing how the data will be collected during the experiment.
Links:
Criterion B: Assessment rubric: Following assessment rubric must be kept in mind while designing your experiment.
7-8
i. explain a problem or question to be tested by a scientific investigation considering a factor affecting strength of an electromagnet
ii. formulate and explain a testable hypothesis using correct scientific reasoning
iii. explain how to manipulate the variables, and explain how sufficient,
relevant data will be collected
iv. design a logical, complete and safe method in which he or she selects appropriate materials and equipment.
Command Terms:
1. Outline: Give a brief account
2. Describe: Give a detailed account or picture of a situation, event, pattern or process
3. Design: Produce a plan, simulation or model
4. Discuss: Offer a considered and balanced review that includes a range of arguments, factors or hypotheses. Opinions or conclusions should be presented clearly and supported by appropriate evidence
5. Explain: Give a detailed account
THE DESIGN LAB
RESEARCH QUESTION (RQ):
Do the number of safety pins increasingly attract to the electromagnet be affected by the increasing number of turns on coil of wire around core?
Sub-question to investigate: Is there direct proportionality between number of safety pins attracted and the number of turns on coil of wire around core?
HYPOTHESIS:
Electromagnet isn’t permanent so electromagnetic strength relies on how many coils are wrapped around (number of turns) the solenoid/core because magnetic field exists due to flow of electric current in the wire and when wire is wrapped around an iron core/solenoid.
Magnetic field strength increases because magnetic field around a wire is circular and vertical/perpendicular to the wire but mainly because magnetic fields from each of the turns in coil add together (i.e. total magnetic fields is more strengthened).
Based on ampere’s law, the increment of Amperian loop occurs due to number of times the current penetrates. Each loop of wire forming the solenoid behaves like a coil that carries current so each coil’s contribution to the net magnetic field causes ‘the greater the number of coils, the greater the magnetic field’ and with each loop of wire around solenoid, density of electric field increases and hence, the vector velocity does, which’s due to the same potential in electric current related with it no matter what number of turns are there around solenoid. The amperes will decrease due to resistance. But as density of electric field generates equivalent amount of magnetic field, then the magnetic field and based on law of Faraday (as there’s absence of displacement of solenoid), there’s direct proportionality between magnetic field and electric field density.
Infinitely long solenoid’s internal magnetic field is given by:
B=μ(subscript 0)nI
(n is number of loops per unit length )
Therefore, more the number of loops, more the safety pins will attract and more the strength of electromagnet because of one of the formulae (B=μoni),where B (magnetic induction: production of current in conductor as it moves through a magnetic field.) is directly proportional to number of loops per unit length.
Greater the number of turns, greater the length and hence, amount of current carrying coil material in use is greater and hence, greater the magnetic field due to higher amount of current flowing through solenoid as a result of increased number of turns.
Based on the formula for coil of wire, which’s H = I * N/L
H= strength of magnetic field in ‘ampere turns per meter’ (At/m)
I= current(in amps) flowing in coil (A)
N= number of turns of coil
L= length of coil in meters (m)
Hence, strength of magnetic field is directly proportional to number of turns in coil(this is needed for executing my experiment as a scientific justification) and electric current flowing in coil and inversely proportional to length of coil in meters.
Therefore, as there’s scientific hypotheses to prove why the number of turns on the coil of wire around the iron core affects the strength of an electromagnet, then the number of safety pins will be increasingly attracted If number of turns will be (relationship between is that independent variable is directly proportional and dependent variable).
VARIABLES:
· Independent: number of turns on coil of wire around iron core which adds more magnetic field lines and makes electromagnet stronger. In an experiment, if we manipulate more than an independent variable, then the cause of the outcome of the scientific experiment will blur from our eyes and hence, there’s only one independent variable because it’s effect(s) on strength of electromagnet is the sole purpose of my experiment and hence, has to manipulated to test its effect(s).
· Dependent: Strength of an electromagnet and hence, the number of safety spins attracted for different number of turns on coil of wire around iron core (independent variable), because the effect of independent variable on this dependent variable will lead to outcome. Linking back to my RQ, the reason why effect of number of turns on number of safety pins is the purpose of my experiment, is that the strength of an electromagnet can be visually, visibly and practically determined in many ways and one of the ways is number of safety pins attracted for different number of turns. Hence, by calculating the number of safety pins attracted for different number of turns, the strength of electromagnet can be determined.
· Controlled:
1. Material of the coil and core(I’d use only 1 ferromagnetic core/iron nail of 15cm and electromagnetic-copper coil each because what I manipulate and check the effects of manipulation is only independent variables and since the purpose of my experiment is to find the direct proportionality between number of safety spins and turns, then material shouldn’t give wrong recordings.)
2. Number and material of the safety pins(I’d use only 6 safety pins{justification for further controlled variables})
3. Electric current in electromagnet(only 1 9V battery will participate/be a part of the electromagnet)
4. Time for electromagnet to pick up the safety pins(8 seconds using timer/stopwatch)
5. Temperature of the electromagnet(I’d execute my experiment in STP).
6. I’d use 3ft of 22-gauge insulated copper wire
LIST OF EQUIPMENT
· 1 DC Battery of 9V
· stopwatch/timer
· 1 ferromagnetic core/iron nail of 15cm/6 inches long
· 6 safety pins
· 3ft of 22-gauge insulated copper wire; This electromagnetic coil should be able to implement these turns—20, 30, 40, 50 and 60 cause this is most appropriate and broad range of turns.
· Pair of small wire strippers
· Gloves
· Cutting plier
· Tape (needed if carefully making the, each non-insulated ends, like a circle doesn’t work out).
PROCEDURE
1. Especially, while repeating the experiment/after establishing the entire electromagnet, wear gloves on your hands so that you don’t have to experience the ‘heating effect’ that happens if the battery is connected with the solenoid for a long time and this happens when you want to repeat experiment for more number of times/more voltage of battery(since this is constant, then you don’t need to justify why electromagnet isn’t disconnected when an experiment is done for a long time).
2. Eliminating the insulation from copper wire doesn't alter the current flow as copper wires are commonly coated in plastic layer for insulation intents and hence, for securing users from electric shock and because electrons can’t be pushed by the battery to flow in the copper wire, then coating must be removed to avoid errors (in noting number of safety pins attracted to the solenoid). Use small(to remove even a tiny part of the ends of the copper wire) copper wire strippers to eliminate 0.6ft of insulation from each of the both ends of the copper wire. Feeding the copper wire by the help of/through this hole and pulling the clippers across the copper wire to strip/eliminate the insulation at both the ends of the copper wire is what you’ve to do.
3. Wrap the copper coil around the iron core for 20 number of loops/turns in one direction so that the assurance for electron flow in a wire happens in such a way that creates a magnetic field because if a direction isn’t followed to wrap up the core with the coil, in an opposite direction, then magnetic fields will repel from one another and thereby, end-up in cancelling each other. Also, Smaller the loops, stronger the battery would be and hence, formulate smaller loops.
4. Don’t overlap each of the turns/loops with one another to avoid errors in readings(since each turn fuels specific amount of magnetic field).
5. Remember to leave that non-insulated ends of 0.6ft to further make it like a circle
(OR) use tape to attach both of them with each other because this is how the electric current can flow in through the copper wire, the solenoid, and this is how the number of safety pins attracted to the solenoid can be noted down further in the experiment.
6. Electric current from the battery can hence flow through the wire and to the entire electromagnet after each of the battery’s terminals are attached to each of the 0.6 ft non-insulated ends of the copper wire.
7. Hold the battery terminals above 6 safety pins by positioning the solenoid above the safety pins, each of the sides of the solenoid on the safety pins and simultaneously start stopwatch/timer by setting it up to 8 seconds. Record the number of safety pins attracted for 20 number of turns.
8. Repeat 1. To 7. For 5 times by increasing the number of turns in this manner— 30, 40, 50 and 60 turns.
9. After 8. Is done, then immediately disconnect the ends of copper coil/wires attached to the battery’s terminals as to save current from blasting/causing a fire hazard and ourselves from great heating effect, i.e. incomplete the complete circuit(solenoid and battery)
SAFETY ISSUES & IMPROVEMENTS
1. One has to bother about heating effect and this is the fundamental/absolute issue because the electromagnet (especially the battery terminals) become quite warm so disconnecting batteries at OFTEN intervals (gap receivable between each trial of experiment) is highly preferable rather than waiting until the entire experiment is done. During the experiment, if there’s heating effect, then use rubber kitchen gloves than the lab gloves to handle the electromagnet.
Wrapping the copper wire tighter to the iron nail is necessary for experiment to work although this supports the heating effect to increase. If the electromagnet device gets too hot then disconnect the wires, wait for a bit but don’t wait until the experiment is completed, because safety of the electromagnet is safety of yours, i.e. extreme could cause burns and rarely, fire hazards. Just like saving earth is saving ‘us’. Also, magnet can be swiftly drained by battery.
2. Another cause of heating effect is that frequently touching the battery terminals throughout the experiment is unrecommended so this is another potential safety issue and hence, don’t touch the terminals for too long as this also makes them heat.
Especially use gloves and if needed(repeated experiments/trials), cloth on it when our intent Is to strengthen the electromagnet and since our intent is to strengthen electromagnet, then we’ve to know that electromagnets become hot as their strength increases (strengthening electromagnet is directly proportional to heat—this is talking about temperature. Hence, see the ‘relativity’ between one of the factors of strengthening electromagnets with the factor we chose).
DATA COLLECTION
The fact that number of safety pins attracted to the solenoid can determine the strength of electromagnet isn’t impractical and is doable so collection of sufficient and relevant data happens between the independent and dependent variable as follows:
Number of turns 'N' (independent variable) & Number of safety pins attracted(dependent variable)
(9,20)
(14,30)
(18,40)
(22,50)
(27,60)
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