We still have a night light in our house. It's used for the kids to see where the toilet is. Without it I fear they will awaken in the middle of the night and start to pee in the broom cupboard. The big girl used to have a squishy nightlight in the form of a GlowWorm. It was mighty comforting to know that she was protected from the unknown beasts under the bed by an insect. We had to get rid of it when the summer of '94 came around and the GlowWorm attracted night-flying bugs that would occasionally carry off small dogs.
Now where would we be without a torch (or a flashlight to those from other hemispheres)? I shudder when I consider all the school camp ghost stories that would have been so totally less scary without the illuminated faces. Consider the cutouts that you attached to the face plate of the torch that turned it instantly into the Bat Signal or the Barbie Signal, or that Signal you used to use with the kid from across the street when you would flash your torch at them after lights out. The best torches are those from the X-Files. Big bright beasts that would put the sun to shame. Imagine no torches in the X-Files. Everything would be completely and totally black. Or they would be forced to shoot the entire show in Liberace's Closet.
Sol (aka The Sun)
I'm in two minds about Sol. 1st, in summer it gets too good at its job. 2nd, in winter it doesn't do its job well enough. 3rd, when you get too much of it, it will cause your neck to peel and your nose to fall off. So, that actually gives me 3 minds. The Sun is the star at the center of our Solar System (just in case you didn't know what that big yellow thing hanging in the sky was). It is the largest object in the Solar System, containing 99.86% of its total mass. Due to its great mass, the Sun's gravity dominates the Solar System and holds all of the planets in orbit. I'm against domination, so I'm against Ol' Sol, except that I can now use the air conditioner I had installed last summer.
A birthday cake without candles, is just a lump of flour and sugar. Cheap party games for kids parties involve candles. Blow out the candles, melt the bottoms (just a little), stick them on a plate and relight the candles. Every child is assigned a candle and the last candle to go out wins that kid a surprise. The surprise - an extra piece of cake that someone with the flu has just spat on trying to blow out those fricken' candles.
Headlights are good when they're in your car. Headlights are bad when they are mounted five high and six wide, they are on 'melt the road' setting and they are attached to the front of a road train barreling towards you at 200km/h. Without headlights where would we put the eyes on cartoon cars? Without headlights how could we flash at the upcoming traffic warning others of a radar trap just down the road? Without headlights how would we see other people on the road and stop from running them down? We wouldn't. We would just have to run people down in the dark and that is nowhere near as much fun.
LED's (Light Emitting Diodes)
A LED is one of those cool little lights that you see on your modem, or indicating the power is on to your computer, or ditto for your speakers, or other little indicators you have around the house. They are cool. They are small. They are powered by means other than I can explain without assistance. They use very, very, very little energy. They are for engineers. They can make your computer room look like the Starship Enterprise, and that, alone, makes them an A.
The electric energy is proportional to the voltage needed to cause electrons to flow across the p-n junction. The different colored LED's emit predominantly light of a single color. The energy (E) of the light emitted by an LED is related to the electric charge (q) of an electron and the voltage (V) required to light the LED by the expression: E = qV Joules. This expression simply says that the voltage is proportional to the electric energy, and is a general statement which applies to any circuit, as well as to LED's. The constant q is the electric charge of a single electron, -1.6 x 10-19 Coulomb.