Research News reports on a technical innovation (thanks to investigator Jan Stradowski for bringing this to our attention):
Crash helmet with a useful smell
The polymer materials or plastics produced by the process start to smell if they develop small cracks. Large cracks really cause a stink.
The smell comes from odoriferous oils enclosed in microcapsules. »Cyclists often replace their helmets unnecessarily after dropping them on the ground, because they cannot tell whether they are damaged or not. The capsules eliminate this problem. If cracks form, smelly substances are released,« explains Dr.-Ing. Christof Koplin…