How to Stop Kids From Biting Their Nails, Sucking Their Thumbs, and More

Knuckle Cracking

That impressive noise is caused by popping gas bubbles in the fluid surrounding the joints. It can, admittedly, feel satisfying (and even macho).

The substitute: Distract your child by giving him some Bubble Wrap to pop, then send him to another part of the house.

Also try: Finger exercises can be a quiet alternative to cracking, according to Greg Irwin, a finger-exercise expert (!) and the creator of the Finger Fitness Program. “They help develop strength and dexterity,” he says. “Tell your kid they’re like push-ups and sit-ups for your hands.” Try finger bends: Press hands together, then gently bend all fingers over to the left, then to the right. (See more at handhealth.com.)

More drastic measures: If the problem persists, establish no-cracking zones, like the dinner table. But don’t worry that your child is in for a whopping case of arthritis someday. One dedicated researcher, Donald Unger, M.D., published a study in Arthritis and Rheumatism in which he cracked only his left knuckles daily for 50 years and found no noticeable difference between his two arthritis-free hands.