Dowling Magnets Electromagnet science kit is ideal for ages 10 - 14 and is used to teach the kids about the magnetic effects. Kit is ideal to build a doorbell and a telegraph system.. - Helps in building a doorbell, telegraph system and even a catapult all using a true electromagnet. - Includes disc, latch and neodymium magnets, compass, straws, wires, sandpaper, switch plates, wood screws, nails, light bulbs, battery holders, iron filings, pre-drilled wood blocks, LED, instruction book. - Electromagnet science kit for grade 5th - 8th helps in building a doorbell, telegraph system and even a catapult all using a true electromagnet.