UNIT 7: Từ tính ppt

www.themegallery.com LOGO Magnetism www.themegallery .com LOGO Magnet The first magnets were known as magnetite or loadstone. www.themegallery .com LOGO Magnetic field lines of a bar magnet www.themegallery .com LOGO Magnet Iron filings "map" of the field of a bar magnet www.themegallery .com LOGO www.themegallery .com LOGO www.themegallery .com LOGO July 29, 2014 Cutting a magnet  An interesting characteristic of magnets is that when you cut a magnet into parts, each part will have both N and S poles. www.themegallery .com LOGO Making Magnets Stroking a piece of unmagnetised iron or steel with a known magnet can make it into a magnet. www.themegallery .com LOGO Making Magnets Placing a magnet alongside a non- magnetised steel knitting needle for some time will magnetise it. www.themegallery .com LOGO The Earth – A huge magnet