“Blue star” experiment

How to make a blue star from starch and salts

How can we make a “star” from deep space in the lab­o­ra­to­ry?

Safe­ty pre­cau­tions

Wear a pro­tec­tive mask, gloves and glass­es, and work in a well-ven­ti­lat­ed room. Ob­serve safe­ty rules when work­ing with fire. If pos­si­ble con­duct the ex­per­i­ment un­der a fume hood.

Warn­ing! Only un­der adults su­per­vi­sion.

Reagents and equip­ment:

  • potas­si­um chlo­rate (10 g);
  • cop­per(II) sul­fate pen­tahy­drate (10 g);
  • starch (15 g);
  • beaker;
  • lighter.

Step-by-step in­struc­tions

In the beaker, we mix potas­si­um chlo­rate, starch and cop­per(II) sul­fate pen­tahy­drate. We sprin­kle the mix­ture onto a fire­proof sur­face and ig­nite it.

Pro­cess­es de­scrip­tion

Potas­si­um chlo­rate is a strong ox­i­diz­er. When heat­ed, it breaks down with the re­lease of oxy­gen, which ig­nites the starch. The flame turns blue be­cause of the pres­ence of cop­per ions.