The climate test

Cell phones can be exposed to extreme temperatures and weather conditions. In the big contraption in the background, Chris Rubie, the manager of the mechanical and environmental lab in San Diego, explains how the devices are tested in the chamber to see how they handle quick changes between very hot and very cold temperatures.

The rain test

Your Nokia phone isn't built to withstand an accidental plunge in the toilet, but a little rain every now and again shouldn't fry it.

"You should be able to go from the car to the house in the rain and your phone should still work," Rubie said.

The bending test

Have you ever sat on your phone? Well, you aren't the only one. In this test, Nokia sees how far a phone can be bent before it cracks.

"We try to push the phone to the limits in the lab, so that they don't break when they're in the field," Rubie said.

The dust and particle test

Shake, rattle, and roll. Nokia puts phones in this case and then pumps in air filled with dust particles and bits of cotton fibers. And then the whole contraption shakes. The phones do a little dance, allowing the dust and cotton particles to work their way into the nooks and crannies of the phones.

The tumbler

Cell phones are dropped, kicked, and tumbled in real life. So Nokia has devised a series of tests to see how different impacts affect cell phones. In this test, a phone is tumbled inside this machine, simulating how a phone might get knocked around inside a purse or backpack.

The jeans test

Since these tests are supposed to simulate real life situations, Nokia has devised a "jeans test." Phones are inserted into Levi 501 jeans filled with coins and other typical pocket items. Then, the phone is jostled around inside to see how it holds up.

Flip phone stress test

Open and close. Open and close. This test literally opens and closes these Nokia flip phones over and over and over to see whether there are any design flaws that could cause the device to break or malfunction.

The slide test

This test slides a phone's face back and forth exposing the QWERTY keypad underneath to make sure there are no defects. Specifically, this test ensures that the slider doesn't damage or rub the keys when the top section of the phone moves back and forth.

The household chemical test

What happens if you spill nail polish on your phone or accidentally spray it with bug repellent? Well, that's what the household chemical test will determine. This tests shows whether chemicals in ordinary household products will damage the phone's outer casing.

Taking a closer look

When one of the stress tests results in a failure, the analysis lab takes a closer look at the device.

Here is a picture of a cell phone that has been sliced down the middle to get a closer look. The damaged area is isolated and examined under a microscope. Sometimes an electron microscope is used to see very tiny parts of the device. And 3D scans can also be used to isolate problems.

Making prototypes

Nokia engineers make prototypes of phones to help them isolate problems and improve product design. In this picture Mike Myers, who heads up one of the laboratories in San Diego, shows off a Nokia phone and its prototype.

Jumbo cell phone

CNET Reviews editor Bonnie Cha tries to get a signal on this jumbo cell phone made using the rapid prototype machine in the Nokia lab.