I am a engineer, but got a tad surprised the other day. I drank something and the glass was empty. No temperature shock anywhere. My cell phone was charging and lying next to it. I heard a funny noise coming form the glass and on closer inspection it was cracked.

Click image for larger version. 

Name:	20151027_225617 (Medium).jpg 
Views:	410 
Size:	20.7 KB 
ID:	6052Click image for larger version. 

Name:	20151027_225644 (Medium).jpg 
Views:	393 
Size:	20.3 KB 
ID:	6053

Does anybody have any idea what could have caused this?