DIY Halloween accessories

A couple of scientific tricks to complete your Halloween costume.

Warn­ing! Only un­der adult su­per­vi­sion.


  • plas­ter of Paris;
  • wa­ter;
  • or­gan-shaped sil­i­cone molds;
  • safe­ty pins;
  • pa­per;
  • gauze;
  • bal­loon;
  • paints;
  • met­al chain.

Step-by-step in­struc­tions

Make some pa­per claws. Mix wa­ter with plas­ter of Paris in ap­prox­i­mate­ly a 1:1.5 vol­ume ra­tio (see the in­struc­tions on the pack­ag­ing for the ex­act ra­tio). Dip your pa­per claws in the mix­ture – they so­lid­i­fy in about 30 min! All that’s left is to give them an omi­nous col­or. Tint a mix­ture of plas­ter and wa­ter and por­tion it into or­gan-shaped sil­i­cone molds. At­tach a safe­ty pin to each of them. In no more than an hour, your omi­nous brooches will be wait­ing for you! Put some gauze on an in­flat­ed bal­loon and cov­er it with plas­ter. To in­crease the dura­bil­i­ty of your bas­ket, use sev­er­al lay­ers of gauze. Fix a met­al chain in the gauze and leave it overnight. Just dec­o­rate it in the morn­ing – and you’ve got a great can­dy bas­ket that can hold 2.5 lbs of sweets!

Process de­scrip­tion

Plas­ter of Paris is pow­dered cal­ci­um sul­fate. Its struc­ture con­tains some wa­ter. As dif­fer­ent man­u­fac­tur­ers pro­duce plas­ter with a vary­ing wa­ter con­tent, it's ad­vis­able to check with the in­struc­tions on the pack­ag­ing. When it in­ter­acts with wa­ter, plas­ter of Paris forms a lot of tiny crys­tals. They grad­u­al­ly merge with each oth­er, so­lid­i­fy­ing the whole mix­ture. These sim­ple crafts will com­ple­ment your Hal­loween cos­tume per­fect­ly – and all the Hal­loween can­dy will be yours!

A sim­i­lar ex­per­i­ment is in­clud­ed in the “Chem­istry of ma­te­ri­als” set from the MEL Sci­ence sub­scrip­tion!