Tuesday's Best Bets on TV

“90210” (8 p.m. The CW): We’d love to tell you that “90210,” the update of Aaron Spelling’s iconic teen drama, is good soapy fun. Alas, The CW deprived critics of review screeners, so proceed with caution.

“Stuff Happens” (9 p.m., Planet Green): Spend a half-hour in the bathroom with Bill Nye. You’ll learn a few things. Nye, the pleasantly nerdish “science guy,” is back on TV with a new 13-part series called “Stuff Happens.” Its goal: to give viewers a better idea of the impact from ordinary items we acquire, use and dispose. Stuff like that has unintended consequences on the local environment as well as the far corners of the world. The first episode has startling facts about the loo (the average person flushes the toilet 140,000 times in a lifetime, with as much as 7 gallons required per flush). Meanwhile, old prescription drugs we chuck into the toilet can breed destructive “superbugs” in the city reservoir. And if we use the wrong toothpaste we endanger orangutans in Borneo. Nye never preaches but, instead, offers simple suggestions to take corrective action. Future episodes head for other problem areas like the bedroom, office, attic and garage.

“The Shield” (10 p.m., FX): The landmark crime series gets set to bid farewell with its seventh — and final — season, and you have to wonder if television’s most crooked cop, Vic Mackey (Michael Chiklis), is doomed to pay a heavy price for his past sins. As we return to the “Barn,” the embattled Mackey is locked in an intense feud with Shane (Walton Goggins), while also dealing with mob threats against his family. The early episodes are excessively convoluted, but the relentless waves of tension and suspense should keep fans riveted until the very end.