The color temperature of a light, measured in kelvins, is its most noticeable characteristic. A candle, at 1900 K, appears orange. Daylight, at 5500 K, is much whiter and bluer. A 5500-K bulb, however ...

After Wanda Cwiecek began treatment for multiple myeloma, a cancer of the blood, she had trouble sleeping and felt emotionally drained. She would get home from work so tired she immediately needed to ...