Summarize this article:

. Read your owner's manual to learn where the jack points are on your car are. Position the jack near the wheel that you suspect has a bad bearing and jack up your car so that the wheel clears the road. Make sure that you take the proper precautions when using a jack so that your car doesn't accidentally fall and injure you. Push and pull on the wheel back and forth to feel if there's any give. If you can push the wheel back and forth, this is a sign of significant bearing damage. Get your bearings replaced immediately if your wheels wobble as you drive. If you suspect a back wheel has a bad bearing, put your hand on the wheel and spin it as fast as you can. If the bearing is bad, it's likely it will make a rattling noise as you turn it. While it's not as severe as a wobbling wheel, rattling wheel bearings should be replaced as soon as possible. The longer that you drive on a damaged wheel bearing, the worse the damage will get over time. If you're still unsure but suspect that there is something wrong with your wheel bearings, you should take it to a certified mechanic so that they can properly diagnose the problem.

Summary:
Lift your car using a jack Wiggle the wheel back and forth to see if there is any movement. Spin the wheel and listen for a rattling sound. Take your car to a professional.