Alysa Brice, Mike Messina, Michael Patrick, Jacob Radatz 8 February, 2014 Background Paper 2014 This research was conducted at the Macomb Academy of Arts and Sciences from September, 2013 to January, 2014. This research tested the influence that electromagnetic fields have on organisms, specifically mealworms. The hypothesis states that as the exposure duration of electromagnetic fields on a population of mealworms increases, the growth rate of the mealworms will decrease, the occurrence of pupation will decrease, and total death will increase. There are five sections of the scientific aspects of this study in this paper: Basic electrical concepts; Electromagnetism; Biological Information on mealworms; Effects of electromagnetic forces on chemicals, inert or organic; and Studies and scientific theory on how organisms are affected by strong electromagnetic fields at the molecular level. Electricity Electricity, in the basic definition, is the existence of an electron pressure gradient across a wire. A system that has a constant pressure difference is called a ‘circuit’. In metals, valence electrons are allowed to pass from atom to atom by molecular orbitals, allowing for a ‘flow’ of electrons to exist [1]. This is visually represented in Figure 1, where the small negative symbols are electrons, outside circles surrounded by boxes represent atoms of a metallic element, and the boxes represent the valence shells of that element.[2] Figure 1: Electrons moving through a wire [2] This motion creates properties used in modern electronics. For instance, when electrons are moving through a wire, the current is a value representing the number of electrons that pass through a point in the wire in an instant, in Coulombs per second, or Amperes [3]. Voltage defines the electric pressure being exerted on the electrons, measured in Joules per Coulomb, or Volts [4]. Both of these relate to the resistance in a wire, being the physical resistance a metal has to electron flow This is measured in Ohms [3]. This relationship is shown below in Equation 1 [5]. In a series circuit (where all electrical objects in a system go across the same wire linearly), the amperage distribution is spread evenly throughout the system. [4] It can then be confidently stated that the fields generated by this research study were evenly distributed throughout the area of the coil. Volts = Current * Resistance (1) The wattage of a circuit is the total energy formed per second, measured in Joules per second, or Watts. The wattage of a circuit can be determined by Equation 2. Watts = Current * Voltage
(2) In reality, electrons move through a wire at relatively slow speeds. The “instant” current production from when the circuit containing a power source is closed (connected) creates an electron pressure difference, making all of the electrons begin to move in that instant. The actual velocity of a single electron is called drift velocity. The equation to determine drift velocity of an electron is shown in Equation 3, where N is the free electron density, A is the area of a cross­section of the conductor in focus, and I is the current passing through the conductor. This is significant information for calculations of the electromagnetic fields generated in this study. Drift Velocity = (I)/(NA)
(3) The coils used to generate the EMF were powered using a modified computer power supply. The process to modify a power supply is relatively simple. First the label on the side of the Power Supply Unit (PSU) was used to determine the different output voltages as well as max output in watts of certain lines. The PSUs that were chosen were manufactured by Dell and have six different output sets: Orange at 3.3 volts with a 17 amp max, Red at 5 volts with a 22 amp max, Purple at 5 volts with a 4 amp max, Blue at ­12 volts with a 1 amp max, White at 12 volts with an 18 amp max, and Yellow at 12 volts with an 18 amp max. These PSUs were chosen due the the fact that there is an internal circuit breaker for each of those lines that will shut down the PSU if a line is overdrawn. In addition to the line breakers, there is also two more breakers that are important: a breaker that will shut down the PSU if the total power output is greater than 305 watts continuously and one that will shut down the PSU if the total draw on both of the 12 volt lines is greater than 264 watts. This is important because the two 12 volt lines were wired together to give a single 12 volt output. Using Equation 2, the max amp output of this line is 22 amps (264W / 12V). Using Equation 1, the minimum total resistance of the wire coil needed to be 0.546 ohms (12V / 22A). The coils that were created are made of 12 American Wire Gauge (AWG) wire or have a diameter of 2.05mm[6]. These coils were also tested for their total resistance using a multimeter. This value was measured to be 0.6 ohms. Using Equation 1, the total amperage that was being passed through the coils was 20 amps (12V / 0.6Ω). Figure 2: Complete Modified PSU and EMF Coil Electromagnetism Electromagnetic fields are fields created by electrically charged objects. They act as both a magnetic field and as an electric field simultaneously. [7] Electromagnetic fields are generated by anything with an electrical current passing through them. Therefore, an electromagnetic field exists whenever a current is present in a conductive material. An illustration of the forces that are exerted from an electromagnetic field are shown in Figure 3, where each illustration shows the forces from various models of field generators. The coil used in this study was similar to subimage (e), where the loop shown was repeated multiple times to make a bundle, as shown in Figure 2. As shown in this diagram, the field generated created forces being exerted perpendicular to the coil in the center, with the force angle changing closer to the wire. [8] Figure 3: Electromagnetic Field directions according to coil design [8] The strength of an electromagnetic field (measured in Gauss) is proportional to the Amperes (or current) passing through a wire. However, voltage has no effect on the strength of an electromagnetic field [9]. Equation 1 shows that amperage would increase proportionately with voltage, according to the resistive value of the conductive material. This is the case in theory, if amperage were able to stay constant while voltage fluctuated. However, this claim is untrue if the resistance is changed to increase voltage, as doing so will actually decrease the current going through a wire. There is a significant difference in electromagnetic radiation in comparison to other types of radiation. For instance, radiation commonly associated with x­rays is called ionizing radiation, which is radiation that can break apart bonds. This is created by nuclear reactions, where the atom breaks down into smaller particles. The kind of fields generated in this experiment are of electromagnetic frequencies, and do not have the potential of breaking chemical bonds [10]. The current going through the coil was direct current, meaning no fluctuation or sinusoid gradient was occurring in the voltage across the coil. As it is not an ionizing radiation, it is considered to be a “safe” form of radiation [11]. The electromagnetic spectrum is shown in Figure 4, where the fields we created are on the far left, beyond radio­frequency. [12] Figure 4: The Electromagnetic Spectrum [12] The fields generated in this research study are, in fact, electromagnetic fields. The information gathered suggest that we created the intended type of field. Ionization radiation is the form of energy that is most commonly associated with interfering with life forms, even though biological organisms are exposed most to electromagnetic fields. Studying the effects of electromagnetic fields were chosen because of the ease of production, the (known) safety of the field, and the pertinence it has in modern societies which are increasing their field generation daily. The law of Biot­Savart states that the magnetic field at a point can be calculated with current and the radius of the point to the center of the wire. Equation 4 is the equation to find this, with I as the symbol for current and mu0 as a constant for 4(pi) x 10­17 Tesla * meters / Amperes. [13] B = mu0*I/2r (4) Biological Information on Mealworms Mealworms, also known as Tenebrio molitor, or Darkling Beetles, are a type of insect that are native to all areas of the world, possibly originating in Europe. The life cycle starts when the larvae hatch after two weeks. The larvae stage lasts about three months, where the mealworms mold their skin a large number of times (an image of this is shown in Figure 5. After the mealworm has grown for a certain number of weeks, pupae begin to form. The pupae last for two weeks before hatching into beetles [14]. Figure 6 shows the standard life cycle of a mealworm [15]. Note the duration listed may not necessarily represent the true duration, and this figure represents the qualitative development cycle of mealworms. Figure 5: Newly­Molted Larvae [15] Figure 6: Life Cycle of a Mealworm [14] A mealworm’s diet mostly consists of grains. If they are kept for domestic purposes, they eat wheat germ or bran, with some apples or potatoes to provide moisture. They can be a pest if they are not caught and removed, as they like dark, damp places that contain grain, such as grain storage bins. Removing them from the area and cleaning up all sources of food will stop the infestation [16]. Temperature and food quality have an effect on the time taken to reach adulthood from hatching, which is usually around 40 to 100 days. Adequate temperature are 30 to 33 degrees Celsius, with 27 degrees Celsius being the average minimum temperature for pupal development [17]. These sources provided the information needed to make sure that the mealworms were kept in an appropriate environment and as a basis for comparison for the growth cycles. EMF Effects on Chemicals This section details chemical interactions with electromagnetic fields. With the information given in this section, the evidence that fields affect matter at a microscopic level can be used to extrapolate possible macroscale results. MRIs, also known as Magnetic Resonance Imaging or Nuclear Magnetic Resonance Imaging, use magnetic fields to align water molecules so that the hydrogen’s axis follow the same pattern. The image generated is formed from a second radio wave that is formed from when the magnetic field is turned off. The average signal strength for an MRI is 0.5 to 1.5 Teslas, or 5000 to 15000 gauss (This research study used coils that generated a roughly 88 gauss field at the focal point). It is commonly regarded that that radiofrequency waves do not contain enough energy to damage tissue [18]. According to the 2012 guidelines from the U.S. Food and Drug Administration, a field rating of up to 8.0 Tesla (80,000 gauss) is considered a “non­significant risk” to human health. However, in a study where patients were exposed to a 9.4 Tesla (94,000 gauss) field, patients noted a “sensory symptoms” related to the exposure. However, long­term exposure data had not been collected. [19] Prior research looked for mutations in DNA. After a certain point when the frequency was increasing, the effects seen were from the heat generated from the EMFs. No significant effects were observed; however, transcription errors in reproducing DNA were noted. Analyzing strands of DNA for mutations relating to EMF is nearly impossible because of the large amount of DNA and the fact that DNA can mutate through other factors. [20,21] Because the most consistent data was on the cellular level, knowing exactly what the effects of the EMF on the mealworms will be difficult. Changes in the room temperature, food, and other environmental factors can change how the mealworms react [18]. EMF effect on Organisms This section consists of studies and science on how electromagnetic fields affect organisms. There are a significant number of studies on different fields from the electromagnetic spectrum and their effects on organism growth, reproduction, and cellular reproduction. However, the studies are largely inconclusive with electromagnetic fields. The studies that do result in significant data will be used to support our hypothesis. A study conducted in 2010 shows the effects electromagnetic fields have on tadpole growth. Two tanks with 70 tadpole eggs each were placed 140 meters from phone antennae, with one box being covered within a faraday cage. The field was roughly 63,000 gauss. In a referenced study, frog embryos produced several types of abnormalities, including microcephaly, abnormal growth, edema, and scoliosis. In this study, tadpole mortality rates increased, growth rates fluctuated, acquired allergies, changes in blood counts, bone abnormalities, and eccentric skeletal patterns [22]. Mealworms could have sensitivity to electromagnetic fields. One group subjected mealworms to electromagnetic frequencies for 15 minutes and the times on time taken to reach food and time taken to move out of lighted areas into a shaded area. Over the testing period, the reaction times decreased, with the irradiated beetles moving slower than the control groups. Animals are suspected of being able to navigate using Earth’s magnetic field, so it is possible that the frequencies generated caused mealworms to become disoriented [23]. In a similar study, bacteria were subjected to EMFs generated by power supplies connected to coils. The shorter amounts of exposure time caused one type of bacteria to decrease growth rate while the other bacterium’s growth rate stayed constant. The several kinds of bacteria did increase growth rate at different frequencies, but only at one specific frequency, which was dependent on the species of bacteria. The research does suggest that EMFs may influence other properties of the bacteria to activate after exposure. [24] Works Cited [1]: Zumdahl, Steven S; Zumdahl, Susan A. AP* Edition Chemistry. 9th ed. Cengage Learning, 2014. Print. [2]: "Electricity ­ Basic Navy Training CoursesNAVPERS 10622 ­ Chapter 3." Electricity. N.p., n.d. 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