Visible crew/equipment: Caroline returns home after her first day at the ad agency. Just as she calls out, "Where is everybody?," the shadow of the boom mic moves across the wall, at the top left side of the screen, and simultaneously we can see the tip of the moving boom mic near the top of the foyer mirror. (00:23:35)
Visible crew/equipment: Jack finds the remains of the potted plant scattered on the carpet beside Megan. Then, just as he lifts Megan in her baby walker, the moving boom pole/mic casts a shadow on the wall, at the top of the screen. (00:31:45)
Visible crew/equipment: When Caroline arrives home in the taxi cab at the end, she sees Joan's red car in the driveway. When she opens the door you can see a reflector screen in the window for a split second. (Use slo-mo if necessary).
Answer: Deep-fried rice noodles. I believe they're known as cellophane noodles. That's actually how they react. You heat oil in a pan and when the noodles hit the oil they "explode" like what you see in the film.