In science he have been making chains that can hold 7 pounds. Our chain is made up of pipe cleaners and string. The pipe cleaners have metal on the inside of them so that makes them strong. The string is for just extra support and it is very hard to break it, we tried. Everything went good, when we tested it out if could hold all of the weight. One time the knot on one of the pip cleaners broke and all of them fell, but now were good.