The first time this appeared in a movie was. . . .

[slaytonf]

I'll start with this:

 

 

 

 

The first toilet in a movie?  Secret Agent (1936).  Madeline Carroll, John Gielgud, Peter Lorre, Robert Young.  Alfred Hitchcock, dir.

[SansFin]

I believe that: The Night the World Exploded (1957) was the first movie to show a real-world electronic computer. It was a: Burroughs B205.

 

Several movies prior to it depicted Differential Analyzers but those were mostly mechanical. 

[Tikisoo]

I've always wanted to know when brassieres were "invented". By that, I mean commercially available, not home made. I recently saw MY WEAKNESS (1933) where showgirls were shown in a dressing room wearing true brassieres (not the old girdle/bra bustiers) 

 

Anything before that?

[OllieTSB]

Tiki, I think NIGHT NURSE (good nurse Barbara Stanwyck, evil Clark Gable, 1931) has a couple of dressing-room scenes - out of 'civvies' then undies then into 'nurse uniforms' and back again.  The nonchalance of Clothes Changing Scenes with continuous dialog among the actresses still made this 'pre-code' but it's interesting to see how truly nonchalant this was, how ordinary, non titillating.  Those scenes MIGHT have 'something less than slips' being used.

 

What about First Rape Depiction?  WILD BOYS OF THE ROAD (Wm Wellman starring his wife as The Victim, 1933).  And WARD BOND as the criminal!  Well, he was dealt with shortly thereafter. 

 

He had 8 more films until he was promoted from freight yard criminal to First Shift Bus Driver for Gable & Lombard in 1934's IT HAPPENED ONE NIGHT.   But jiminy - 23 films in 1934 under Ward's belt?   "Bond - Ward Bond" indeed.  Shades of Silent Filmdom!