Traffic lights experiments focus: understanding the red traffic light is applied parallel circuit stop, green line on the crossing was safe. Every time I hear this song is not the songs, they think of the traffic lights on the road it? But do you know why a traffic light will be red for a green it? After completing this section will test you may understand the mysteries of. Purpose: recognize and understand their application of electronic components in contact with a simple circuit experiment Cognition: the role of the various components: battery - to provide energy; bulb - converts electrical energy into light energy; Wire - connecting components and conduct current, which is electricity electricity transmission objects along a given direction toward a regular flow is the invisible; switch - control circuit; battery box - Place the battery. Current flows through the circuit is called a circuit, also known as conductive loop. The most simple circuit is determined by the power supply, load, wires, switches, switches and other components of the composition. Circuit called conduction pathway. Only path, only the current through the circuit. Called circuit breaker or disconnect one place open. If the circuit between the positive and negative power supply directly connected but no load is called short-circuit, this situation is never allowed. Another kind of short circuit refers to the two ends of a component directly connected, this time from the direct current flowing through without turning point after the element, the element of this case is called a short circuit. Open (or open) is allowed, and the first short-circuit must not be allowed, because a short circuit will cause the power supply to be burned with appliances, ammeter. 1. Experimental preparation: understanding experimental equipment: wire millet bubble, flat battery box column, cover, switches, base, shade holder. 2. red yellow bulbs were followed by three millet penetrated the back cover, and then fastened to the seat with the lampshade. 3. The circuit connection; first with a small pair of scissors to millet bubble three white lines (or red) cut, peeled, the three copper wires twisted together, then connect one end of the connection after the extended battery box with a wire; 4. Place millet bubble three red (or white) and respectively connected to one end of the three-stage switch sheet; 5. Finally, the connection switch and the battery compartment, the circuit connection is completed, replace the battery can. Tip: Do not use excessive force when installing parts causing damage. Widgets more, do not put small parts into the mouth, patience to teach children to be installed. Knowledge Development: The world's first gas lamps consisting of red yellow and green traffic lights appeared in 1868 in London, England. Through continuous improvement it appears the three-color lights from red to yellow-green component and has been in use ever since, using three colors, red yellow and green is based on optical principles, long-wavelength red light, strong ability to penetrate the air at the same time than the other signal more noticeable, so as to prohibit passage of the signal, the longer the wavelength of yellow light, strong penetrating capacity of air, so as a warning signal, the use of green as notification signal, because the difference between red and green maximum, easy to resolution, the display is also far away. You know driveway lights that it? 1) When the green arrow lights to allow the direction indicated by the vehicle lane traffic; 2) when the red light or arrow lights fork prohibit vehicular traffic lane; 3) the direction of the arrow indicates the direction of the lights to the left, up, right, respectively, Turn left, go straight, turn right; 4) flash warning lights flashing yellow light for sustained, suggesting the vehicle, pay attention when watching pedestrians, confirm safe passage; 5) road and rail level crossing with two alternately flashing red lights or When a red light, said the ban vehicles, pedestrians, red light is off, it indicates that allow vehicles and pedestrians. Experiment: the experimental work to draw traffic light circuit. http://www.bjxwt.com Beijing precedent http://www.bjxwt.com.cn Beijing Education Development Co., Ltd. stationery small child playing precedent http://www.xianhe-edu.com Beijing Education Development Co. Company Stationery Factory