Conductivity of solutions lab report

The lab assignment for this class is intended to instruct the students as to the pieces of the scientific method in a hands-on fashion. Through demonstrations by the instructor, and designing an experiment of their own, students will gain an appreciation for the scientific method in a hands-on fashion. The first part will consist of an in-class lab demonstration by the instructor. The second part will consist of a designed experiment where students will be guided through hypothesis formation and testing. The third part will consist of a student designed experiment which attempts to answer student-generated questions about their own physical environment. All three labs will be followed by a lab report that will be assessed using the DSL 100 Journal grading rubric.Lynn University Dr. Jonathan Smith Laboratory #2: The Basics of Electricity Introduction Let’s get started by reviewing the phenomenon of electricity and electric charges. These are based on the nature of atomic-level particles called protons and electrons. In the scientific world, we have arbitrarily named the protons as “positive” and electrons as “negative”, but what’s important is that they are opposite charges. What is known about how these charges interact with each other? Well, Coulomb’s Law tells us that we can measure how these opposite charges are drawn to one another in a precise equation by understanding the amount of each charge and the distance between them. One Coulomb of charge is measured as 6.24 x 1018 electrons, or the charge of those electrons. (Anixter, 2017) This force of attraction between separated charges relates directly to the electromotive force called Voltage. Voltage describes the force that drives charged particles from one end of an electric circuit to another. The technical measurement of 1 Volt is the force required to push one Ampere, or Amp, of current through a conductor with 1 Ohm of resistance. (Anixter, 2017) What are those last two components all about? André-Marie Ampère described the flow of free electrons through a conductor as what we experience as electric current. Technically measured, 1 Ampere is 1 Coulomb of charge flowing past a point in a conductor in 1 second. (Anixter, 2017) The Ohm is the measurement of resistance in a conductor. All conducting materials resist the flow of electricity to some degree as the electrons interact with the atoms of the material they are flowing through. Resistance changes based on 3 things: 1) the larger the diameter of a conducting wire, the lower the resistance; 2) the nature of the material at the atomic level; whether electrons can flow freely through the material or whether they interact strongly with the nuclei of the atoms; and 3) the higher the temperature of the conductor, the higher the resistance, mostly due to the increased kinetic energy of the individual atoms. (Anixter, 2017) As per Ohm’s law (V = I x R), when voltage is constant, resistance of a conductor is inversely related to how easily electricity flows through the conductor, meaning the higher the resistance, the lower the flow of current and vice versa. In this laboratory, we will be investigating how water functions as a conducting solution. Going back to Benjamin Franklin’s kite experiment, we have always observed how water conducts electricity. Because water is a polar molecule, meaning it has a slightly positive and slightly negative end, it’s easy to see how electricity can flow through water using those charged ends to transport the charge from one end to another. However, when other scientists have tested the flow of electricity through pure water (meaning all other molecules have been filtered out), the water does not conduct electricity efficiently. The efficiency of flow can be determined by measuring the resistance in Ohms using a multi-meter. The less resistance, the higher the flow of electricity. Lynn University Dr. Jonathan Smith We also know that water is a universal solvent, meaning that it dissolves most substances that have any sort of polarity or partial charges, and it easily dissolves ionic substances due to the polar nature of water attaching to each ion or partial charge. Since charged particles dissolve easily in water, is it possible that these dissolved substances that we cannot see with the naked eye are what create the highly conductive nature of water? Perhaps if we purposely dissolve substances that have charges and compare the resistance of the solution of charged particles in water with the resistance of pure water, we can determine whether or not it’s the water or the dissolved substances that carry the electric current. For example, table salt dissolves in water into its constituent components of Na+ ions and Cl- ions. These ions might help to facilitate the flow of electricity between two probes of a multi-meter. Our hypothesis is that a solution of salt in water conducts electricity better (or with less resistance) than pure water. A Multi-meter is a tool used by electricians to determine the current status of electrical circuits safely and accurately. The Ohm setting is used to measure the resistance of electric flow in a conductor using the battery as the voltage, and the comparison between amperage of the probes to measure resistance. It uses an analog-to-digital converter to convert analog electrical signals to a digital read out. 2 Lynn University Dr. Jonathan Smith To conduct the experiment,