K is for Kelvin

In photography, there is so much to learn about light, for example, the source of light, the direction of light, and even the color of light - after all photography is "writing with light". In digital photography, the color of light is measured on the Kelvin temperature scale (K), ranging from 2000 to 10,000 - 2000 will cast a blue tint to your images and 10,000 will cast a red/orange tint to your images.

2500 Kelvin

5000 Kelvin

10000 Kelvin

This is a lot to take in and I, like you I expect, have no desire to become a scientist or a physicist. Suffice it to say:

1. Light has color and it's temperature is measured in Kelvins (K).
2. Rightly or wrongly, in digital photography color temperature and white balance are often used interchangeably. 
3. On most DSLRs, you can shoot on Auto White Balance and leave white balance decisions to the computer in your camera, or .... you could use one of the handy pre-sets.
4. Most digital SLRs have common white balance pre-sets which will allow you to shoot on a white balance that more accurately and consistently matches the light in your shooting environment, for example:
   1. Incandescent (3000K) - good for shooting indoors under artificial lights; cools the image down.
   2. Fluorescent (2,700-7,200K) - good for shooting under strip lighting situations; warms the image to compensate for the slightly green tint these images often have.
   3. Direct Sunlight (5,200K) - a mid-temperature setting good for shooting in daylight
   4. Flash (5,400K) - warms up light from a flash which is cool but not as green as fluorescent light.
   5. Cloudy (6,000K) - good for shooting on cool-color overcast days and provides warmth to the image.
   6. Shade (8,000K) - good for shooting in cooler-color conditions than even a cloudy day, like dusk; adds even more warmth.

Play with these pre-sets and as you do, you will begin to grasp white balance even if you never understand the Kelvin thing. AND, remember, if you shoot in Raw, you have a lot more flexibility in adjusting the white balance in post-processing than if you shoot in JPEG.