look at vs observe

look at

verb
  • To observe or watch (something). 

  • to face (to be presented or confronted with; to have in prospect) 

  • To consider. 

  • To study (something) visually. 

observe

verb
  • To notice or view, especially carefully or with attention to detail. 

  • To take note of and celebrate (a holiday or similar occurrence); to follow (a type of time or calendar reckoning). 

  • To comment on something; to make an observation. 

  • To follow or obey the custom, practice, or rules (especially of a religion). 

How often have the words look at and observe occurred in a corpus of books? (source: Google Ngram Viewer )