Ionization energies
INTRODUCTION: The ionization energy of an atom measures how strongly an atom holds its electrons.The ionization energy is the minimum energy required to remove an electron from the ground state of the remote gaseous atom The first ionization energy, I1, is the energy needed to remove the first electron from the atom: i.e. the most loosely held electron! Na(g) -> Na+(g) + 1e- The second ionization energy, I2, is the energy needed to remove the next (i.e. the second) electron from the atom Na+(g) -> Na2+(g) + 1e- The higher the value of the ionization energy, the more difficult it is to remove the electron As electrons are removed, the positive charge from the nucleus remains unchanged, however, there is less repulsion between the remaining electrons INVESTIGATION: Periodic trends in ionization energies First ionization energies as a function of atomic number * 1.Within each period (row) the ionization energy typically increases with atomic number * 2.Within each group (column) the ionization energy typically decreases with increasing atomic number HYPOTHESIS: * Investigation 1: As the effective charge increases, or as the distance of the electron from the nucleus decreases, the greater the attraction between the nucleus and the electron. The effective charge increases across a period, in addition, the atomic radius decreases * Investigation 2: As we move
An investigation into the effect of temperature on a squash ball
An investigation into the effect of temperature on a squash ball For my experiment I will be using a blue spotted squash ball. This is because the blue spotted ones are designed to have the most bounciness. This is will make it a lot easier to judge the height of the ball's bounce making my experiment more accurate. I'll set up my equipment to the diagram below. Then I'll put the squash ball in a beaker and then put the beaker in a water bath. The water will obviously be heated with a Bunsen burner which will then heat the ball up. I've chosen this method so the ball doesn't get wet, and the experiment is fair. I will then drop the ball from a height of 2 meters. It will be landing onto a piece of MDF (Medium Density Fibreboard) to make sure the surface won't affect my results, so it's more of a fair test. To judge how high the ball has bounced, I will be using my eyesight. Diagram Equipment list 4 different coloured squash balls Beaker Water bath 2, 1 meter rulers MDF Kettle Ice Thermometer Stopwatch Tongs I did a preliminary experiment to see if my method would work and if there were any problems with the way I will conduct my experiment. Preliminary Results Temperature (ºC) Distanced Bounced (Cm) 90 81 40 68 0 20 Factors affecting my experiment * If I use different squash balls of different elasticity it will affect the bounciness of the
Thermal insulators.
Zeadon Jamil Thermal insulators Aim To investigate different materials for the most effective thermal insulator for a house. Introduction Heat transfer is the gain and loss of energy. There are three ways in which thermal energy can be transferred: * Conduction * Convection * Radiation Conduction - this is when energy travels from molecule to another. When one molecule receives energy it begins to vibrate and hits other molecules and makes them vibrate. And will spread throughout the object. Convection - this will only occur in gases and liquids. When heat is applied to the bottom of the substance, it will heat it up. When it heats up, it will rise to the top, forcing colder areas towards the heat source and then they will receive energy and rise to the top, etc. Radiation - it travels in waves. When it hits a molecule it makes it vibrate. I will be concentrating on conduction, as this is the main way in which thermal energy is transferred lost from housing. Which means that I need something that is a bad thermal conductor (good thermal insulator) to keep the amount of conduction to a bare minimum? Plan I am planning to test five materials (paper, cling film, cloth, bubble wrap and plastic) and one control, three times and find the average (to ensure accuracy). Whichever material changes the temp of the water the least is the best insulator. I will wrap
The factors affecting the resistance of a metalic conductor.
INVESTIGATION: THE FACTORS AFFECTING THE RESISTANCE OF A METALLIC CONDUCTOR Metals conduct electricity because the electrons in the metal can move about inside the structure. These electrons are called free electrons. Electricity is conducted through a conductor by means of free electrons. Atoms consist of protons, electrons and neutrons. The protons and neutrons make the nucleus of an atom while the electrons circle the outer area of the atom. Electrons in metal are able to move freely and are used as current in an electric circuit. This is because they carry a charge and can move all around the circuit with this charge. While these electrons are travelling around the circuit, atoms are sometimes in the way, causing the two to collide. This takes out some of the energy from the electron and transfers it to the atom. This is how resistance occurs. The number of free electrons depends on the material and the more the free electrons in a substance the better the material as a conductor. All conductors offer resistance to the flow of current. The conductor's atoms determine this resistance. For example copper atoms offer negligible resistance to an electric current because a significant proportion of its electrons are free to move from electron to electron. Thus copper is commonly used as a conductor. Current, is the flow of electrons around a circuit. Those materials,
Resistivity Coursework
Resistivity Coursework Theory suggests that the resistance of a wire is found with this formula: R=?L/A R = Resistance ? = Resistivity of wire L = length of wire A = cross-sectional area I will now perform an investigation to confirm the legitimacy of this formula and confirm a value for ? in a Nichrome wire. Planning A4c: Fully labelled Diagram A4d, A6d: Comprehensive list of Apparatus including Instrument Ranges Variable power supply unit Analogue ammeter, accuracy 0.01A, range 0 to 1.0A Analogue Voltmeter, accuracy 0.1V, range 0 to 5V Copper leads x5 Crocodile clip x2 Nichrome Wire (diameter=4.57 x 10-4m) Ruler, accuracy 0.001m, range 0 to 1.000m A2c: Safety Confirm the Initial power supply is at 0 volts other wise huge voltages will most likely cause unnecessary heating in wires including the Nichrome not only a hazard but may compromise my readings. Make sure my practical investigation is free of all or any obstructions; any unnecessary wires may cause a short circuit leading to damaging the power supply unit, ammeters and voltmeters. A4b, A6a: Identifying Variables and Constants The variables in this investigation are voltage (V), resistance (R) and length of Nichrome wire (L). Resistance and length are directly proportional to each other. Constants are current (I), cross sectional area of wire (A) Resistivity (?) and temperature of the Nichrome
Ohm's Law coursework
GCSE Physics- Ohm's Law coursework Aim: I have chosen to investigate how the resistance of a wire is affected by the length of the wire. What is resistance? Electricity is conducted through a conductor, in this case wire, by means of free electrons. The number of free electrons depends on the material and more free electrons means a better conductor, i.e. it has less resistance. For example, gold has more free electrons than iron and, as a result, it is a better conductor. The free electrons are given energy and as a result move and collide with neighboring free electrons. This happens across the length of the wire and thus electricity is conducted. Resistance is the result of energy loss as heat. It involves collisions between the free electrons and the fixed particles of the metal, other free electrons and impurities. These collisions convert some of the energy that the free electrons are carrying into heat. How is it measured? The resistance of a length of wire is calculated by measuring the current present in the circuit (in series) and the voltage across the wire (in parallel). These measurements are then applied to this formula: V = I ´ R where V = Voltage, I = Current and R = Resistance This can be rearranged to: R = V I Ohm's Law It is also relevant to know of Ohm's Law, which states that the current through a metallic conductor (e.g.
Aim: The aim of this experiment is to see how the length of a nichrome wire affects its resistance.
Resistance in a wire Prasal. S. Rohra IX-B Introduction: Resistance is the force which opposes the flow of an electric current around a circuit. Resistance is measured in ohms (). Resistance involves collisions between the free electrons, the fixed particles of the metal and its impurities. This collision creates friction due to which some of the energy the free electrons are carrying is converted into heat. Resistance can be measured using the Ohm's Law (named after Georg ohm): - Resistance of a wire can be affected by various variables like thickness, purity, temperature, material and length out of which length is an important one. There is a direct relationship between the length of a wire and its resistance because as the length of a wire is doubled so is the resistance. As resistance is a result of collisions between the free electrons and the fixed molecules of the metal of a wire, there will be more collisions if there is a longer wire (as it is a longer path to travel for the electrons). If there are more collisions that means there is more resistance. Example: If there are 10 free electrons and have to go through 2 wires: a)10 cm and b)20 cm, there will be more resistance in wire b) as there will be more molecules in the electron's path in wire b) than in wire a). Aim: The aim of this experiment is to see how the length of a nichrome wire
Resistance of a wire coursework. In my experiment I shall be using different types of wires with various lengths and widths. Through these I shall be testing the resistance which is caused by electrons.
Coursework: Resistance of a wire Introduction: I plan to do an experiment on the resistance of a wire. In my experiment I shall be using different types of wires with various lengths and widths. Through these I shall be testing the resistance which is caused by electrons. The electrons lose energy as they try to move past atoms. The effects are as follows: . The current is reduced and energy slows them down. 2. The potential difference of the electricity in the wire increases as it loses energy. 3. The wire is heated up by the energy that is lost from the electrons. A correlation between the length and the width of the wire is that the longer and wider the wire is, the more atoms there are. The resistance is larger wires should be higher. You can calculate the resistance by using Ohms law. This is the equation for Ohms Law: Resistance (R) = Voltage (V) / Current (I) This equation can then be rearranged to give voltage or current. Variables: Temperature: Atoms in the wire will vibrate as the temperature increases. The vibrations increase along with the temperature. This makes it more difficult for the electrons to avoid the particles in the wire. This causes the resistance to increase as the electrons spend more energy in collisions or trying to avoid atoms. Length: The longer the wire is, the more atoms there will be for the electrons to pass. This makes
Q. How is resistance affected by changing the length of a piece of nichrome wire in a simple circuit?
Q. How is resistance affected by changing the length of a piece of nichrome wire in a simple circuit? Problem: I have been asked to investigate how resistance is affected by changing the length of nichrome in a simple circuit. What is resistance? Resistance is anything that slows down the flow of electrons/current. This is called a resistor. Resistors are either small pieces of material or long coiled pieces of wire that don't conduct electricity very well. For example, bulbs do not conduct electricity as well as a piece of copper mainly because copper contains loads of free electrons. Examples of resistors: * Hairdryer * Toaster * Filament in a bulb The filament in a bulb is a great example of a resistor. It is a very thin wire so it slows down the flow of electrons and takes energy away from the electrons as they struggle to get through it. The energy is then changed to heat and light. Current: The flow of electrons in a circuit is called the CURRENT. Current is measured using an ammeter. Current is measured in units called AMPS. Voltage: Voltage is the amount of energy that the electrons have. It is measured using a voltmeter. Voltage is measured in units called VOLTS. In order for me to try and prove my original question I am going to have to carry out a number of experiments. In these experiments I am going to have to record the volts, and amps in order
To investigate How the Length of Wire affects its Resistance.
Coursework: "How the Length of Wire affects its Resistance" Aim To investigate How the Length of Wire affects its Resistance. Hypothesis I predict that if "the length increases then the resistance will also increase in proportion to the length". I think this because the longer the wire the more atoms and so the more likely the electrons are going to collide with the atoms. So if the length is doubled the resistance should also double. This is because if the length is doubled the numbers of atoms will also double resulting in twice the number of collisions slowing the electrons down and increasing the resistance. The diagrams below backup what I have written above; Long Wire Short Wire Flow of Current Wire Particles (Resistance) The diagram shows that if the wire is longer the same amount of current has to pass through a longer distance of space, and in a longer piece of wire there will be more atoms in the way increasing the resistance. When compared to a shorter wire the same amount of current has to pass through a shorter distance, and there won't be as many atoms in the way so the resistance won't be as great. Method . I will set up the apparatus as shown in the circuit. 2. I will get a wire of length 20cm and connect it to a wooden ruler. 3. The first crocodile clip will be connected to the
