How to make a "gold" bracelet

Making a unique “gold” bracelet at home

Safe­ty pre­cau­tions

Per­form this ex­per­i­ment only un­der adult su­per­vi­sion.

Equip­ment

  • cop­per wire;
  • zinc gran­ules;
  • alu­minum cup;
  • burn­er;
  • zinc sul­fate so­lu­tion;
  • thin-nose pli­ers.

Step-by-step in­struc­tions

Twist a cop­per wire into a spi­ral. Pour some zinc gran­ules into an alu­minum cup, place the cop­per spi­ral on top, and cov­er with a so­lu­tion of zinc sul­fate. Place the cup on a burn­er and heat for 35 min­utes. With time, the en­tire wire will turn sil­ver. Re­move the wire from the so­lu­tion, wash it with wa­ter, and dry it with a pa­per tow­el. Heat the spi­ral on the burn­er un­til it be­comes uni­form­ly gold­en. Cut the wire and twist it into rings to make a “gold” bracelet!

Pro­cess­ de­scrip­tion

When the so­lu­tion is heat­ed, the zinc trans­fers some elec­trons to the cop­per wire, giv­ing the wire a neg­a­tive charge. Zinc ions Zn²⁺ are con­stant­ly switch­ing mov­ing be­tween the so­lu­tion and the wire. The neg­a­tive­ly-charged wire at­tracts charged zinc par­ti­cles – Zn²⁺ ions – which are re­duced on the wire and then set­tle on the cop­per. At the same time, some metal­lic zinc from zinc pel­lets is ox­i­dized and moves into so­lu­tion in the form of Zn²⁺ ions. As a re­sult, the cop­per coin is slow­ly cov­ered with a lay­er of sil­very metal­lic zinc. Wash it prop­er­ly with wa­ter. If you fur­ther heat the wire over the burn­er, the zinc and cop­per atoms be­gin to mix, yield­ing a “gold­en” al­loy – brass.

A sim­i­lar ex­per­i­ment is in­clud­ed in the “Alche­my” kit for kids from the MEL Chem­istry sub­scrip­tion!

Try it