a. Determine the factors that affect the strength of the electric and magnetic forces.
Electricity, electric charge and electric field
Electricity is the flow of electrons. It is created by electric charge or the property of an object that allows it to exert an electrical force on another object without contact. In order to exerts this force, an electric field is created. An electric field is the space around a particle through which an electric charge can exert the force.
Example - Electricity operates things such as computer. The electrons flow through the computer, and the energy allows the computer to function. |
Factors that affect the strength of the electric forces.
Electrical forces are affected mainly by 3 factors.
The first factor is the amount of charge imbalance between the objects. That means that the greater the imbalance, the greater the strength of the electric force. Example - In thunderstorms, the charge imbalance between the ground and the clouds are great, and that causes lightning to have a significant amount of energy and strength. The second factor is the voltage of the source. With larger voltage, the strength of the electric charge increases, therefore increases the force. Example - Using a battery with less voltage to light a lightbulb will produce weaker energy, and this make the light dimmer than using a battery with higher voltage. The third factor is the quality if the conductor. That is, how well the conductor can conduct electricity. If the conductor has a low resistance, it is a better conductor, since it allows electricity to flow through more easily, increasing the strength. Meanwhile, if the conductor has a high resistance, it is a poor conductor of electricity, since it doesn't allow electricity to move through easily, decreasing the strength of the force. Example - Copper, which are used for electrical wires, has low resistance, allowing most electricity to flow through it. Plastic, on the other hand, has a high resistance, therefore does not allow much electricity to flow through, decreasing the strength. |
Magnet, magnetism and magnetic field
A magnet is an object that attracts certain materials. The force that is exerted by a magnet is called magnetism. The push or pull of magnetism can act at a certain distance, which means the force can be exerted without physical contact. Magnetism has an area around it that allows the force to be exerted, called the magnetic field.
Example - On the refrigerator, there is a magnet, use to attract the seal on the door. When the door is within the magnetic field, the magnet use magnetism to shut the door, attracting the seal without any physical contact needed. |
Factors that affect the strength of the magnetic force
Magnetic force is affected mainly by 3 factors.
The first factor is the distance between the magnets and/or the materials. Every magnet has a magnetic field around them that allows them to exert magnetic force. But the field only covers a certain distance. The farther away the magnets and/or the materials are, the weaker the force. If the distance between the magnets and/or the materials are greater than what the field can covers, the force cannot be exerted. Example - The magnet in the refrigerator can only exerts the force once the seal come close enough, or within the magnetic field of the magnet. The second factor is how aligned the magnetic domains are. Magnetic domain is a group of atoms whose magnetic fields are pointing towards the same direction, or aligned. This affect how magnetic a material is. In nonmagnetic materials, the magnetic domains point to many directions and are not aligned. In magnetic materials, the magnetic domains are partially aligned, but not all of them. In magnets, the magnetic domains are all aligned, which means they all point to the same direction. Example - Wood is a nonmagnetic material, since its magnetic domains all point towards different directions, therefore magnetic force does not affect it in any way. Iron is a magnetic material, since its magnetic domain are partially aligned, and therefore can be affected by the magnetic forces cause by magnets. The third factor is the distribution of magnetism on a magnet. Magnetism is not distributed evenly throughout the whole magnet. The parts if the magnet where magnetic force is the strongest are called magnetic poles, or the two ends of a magnet. So when materials are put close to a magnet, they always have the tendency to move towards the poles, which ever closest. Example - When putting iron close to a magnet, the iron always try to move towards the end of the magnet, which ever pole is the closest to it. |
b. Create a working circuit for a device that can be use in everyday life.
Circuits
A circuit is a closed path through which a continuous charge can flow. The path is provided by a conductor, or a low-resistance material. A circuit typically contains 4 main parts, including a voltage source, a conductor, a switch, and a resistor (energy user), or an electrical device that slows the flow of charge in a circuit, and turn it into other form of energy, to be able to work.
Example - On the picture on the right, there is a diagram of a parallel simple circuit that can be use in everyday life. On the circuit, there is a voltage source (battery), conductor, a switch, and a resistor (light bulbs). If the switch is turned on or off, this affect both light bulb. The electrons flow inside the first loop, and at the same time, some electrons also flow in the second loop, flowing from the positive electrode and return to the negative electrode. |