The electric lamp
Long ago people lit their homes with fires, torches and burning oil. In the 1780s the Swiss scientist Ami Argand greatly improved the oil lamp: instead of a flat wick he used a tube-shaped wick and a glass chimney, so the lamp burned much brighter and without smoke. In the mid-19th century kerosene lamps spread widely. In the 1870s the Russian engineer Alexander Lodygin and the American Thomas Edison made incandescent bulbs: a thin wire inside heats up and glows when current passes. Later came more economical fluorescent and LED lamps; an LED lamp uses much less electricity for the same light. Lamps get their energy from the mains or from a battery. Used batteries contain harmful substances: we do not throw them in ordinary rubbish, burn them or open them; we hand them to a collection point. Swallowing a button battery is very dangerous. (Note: the textbook dates Argand’s lamp to the 13th century, but it was really made in the 1780s.)
You need: a notebook, a pencil, an adult. Steps: 1) Walk round your home with an adult and record every light source in a table (room, lamp type). 2) Tell the kinds apart: a round glass bulb with a thin wire inside is incandescent; a long tube is fluorescent; a lamp with many tiny dots or a cool body is often LED. 3) Work out in which room the light stays on longest. 4) List 5 devices that run on batteries and look at what batteries they use. 5) Prepare a lidded box at home for used batteries. Safety: do not touch a lamp that is on or was just turned off because it is hot; unscrewing lamps and touching sockets or wires is for adults only; do not open, throw or put batteries in your mouth; keep them away from small children.