Solutions to Circuit Construction Kit 2.1 a) One light bulb, One battery, Two wires Describe what you observe: One wire connects the bottom of the bulb to a battery terminal while the other wire connects the side of the bulb covered in metal to the other terminal of the battery. The bulb lights. Explain what you observe using the energy approach: The energy of the battery is converted into the thermal and light energy of the bulb. b) One light bulb, one battery, one wire Picture: Describe what you observe: One wire connects the side of the bulb covered in metal to a battery terminal. The other battery terminal touches the bottom of the bulb directly. The bulb lights. Explain what you observe using the energy approach: The energy of the battery is converted into the thermal and light energy of the bulb. c) Summarize i. A light bulb must be connected to a circuit in a certain way: the bulb must touch the other circuit elements at the bottom of bulb and on the side of the bulb at the metal base. ii. The energy to light the bulb comes from the battery.
2.2 a) b)
c) The bulb lights when: 1. The circuit path is closed and connected to a battery 2. The bulb is connected into the circuit at the bottom of the bulb and on the side of the metal base. d) The bulb will NOT light when: 1. The circuit path is open 2. The bulb is not connected into the circuit at the bottom of the bulb AND on the side of the metal base. e) The energy to light the bulb comes from the battery. Our theories about the structure of matter include the idea that matter is made up of tiny, moving parts. Matter is made up of charged particles. separate these charges in a way that produces an electric field and a potential difference between the two battery terminals. This electric potential energy is converted to kinetic energy (the charges accelerating) and to thermal and light energy when the bulb gets hot and is lit. f) The internal structure of the light bulb is also made up of charges that move. Inside of the light bulb, we can see the filament, but we do not see where the filament ends. The pieces of the filament end at the bottom of the bulb and on the side of the bulb where the metal coating is. We need to connect the bulb to wires or batteries at these points so that the moving charges can follow a conducting path that leads to the filament. g) The filament is made up of metal and the filament leads to the bottom of the bulb and the side of the bulb where it contacts the metal material at the base of the bulb. The filament will only glow when the circuit elements, which must include a battery or some mechanism to maintain a potential difference, are connected to these points so that the charges can move within the metal. When there is current through the filament, the interactions of free electrons with the lattice of atoms within the filament make the filament very hot. When the filament gets hot enough to glow we see light.
2.3 a) Dollar bill Paper clip Penny Eraser Pencil Lead Hand MATERIAL DESCRIBE WHAT YOU OBSERVE No charges moved Charges moved quickly and then the paperclip and the battery were on fire. Charges moved quickly and then the penny and the battery were on fire. No charges moved Charges moved slowly. No charges moved. No charges moved. EXPLAIN WHAT YOU OBSERVE USING THE ENERGY APPROACH difference but the dollar bill in the conducting path does not allow the charges The work done by the battery results in a change in kinetic energy of the charges (they move) and the production light and change in internal energy of the paper clip. The work done by the battery results in a change in kinetic energy of the charges (they move) and the production light and change in internal energy of the penny. difference but the eraser in the conducting path does not allow the charges The work done by the battery results in a change in kinetic energy of the charges (they move). difference but the hand in the conducting path does not allow the charges
Dog difference but the dog in the conducting path does not allow the charges b) The purpose of a switch is to allow us to open a conductive path if we choose to. When the switch is closed the path is a conductive path. When the switch is open, it allows a dielectric, such as air, into the once conductive path in order to stop the current. c) You can set the battery on fire using just the battery and one wire connected to both terminals (The simulation did not allow me to do this though, I actually had to use one battery and two wires, but in real life you could accomplish this with just one wire.) 2.4 a) In order to have a continuous flow of electric charge through a metal wire you need: 1. A potential difference 2. A charge conduction pathway b) There needs to be a device present in the circuit that is capable of converting electric potential energy into some other forms of energy. Batteries do work to separate electric charges in order to create a potential difference that will lead to a flow of charge from one terminal through the conductive pathway (wires, etc.) back to the second terminal of the battery. 2.5 Pose Your Own Questions (Varied) Example Questions: Why are there no external leads to an incandescent bulb but there are for a neon bulb? Would it be possible to replace the metal base of the lightbulb with a rubber one?
2.6
2.7 In both pictures, a battery is present in order to maintain a potential difference. The parallel circuit requires more wires than the series circuit. In both circuits, the bulbs are of equal brightness to the others in the same circuit; however, the bulbs in the series circuit are dimmer than the bulbs in the parallel circuit.