The British thermal unit (BTU or Btu) is a traditional unit of work equal to about 1055 joules. It is the amount of work needed to raise the temperature of one pound of water by one degree Fahrenheit (Physical analogue: one four-inch wooden kitchen match consumed completely generates approximately 1 BTU).
Blisters on feet can be caused by numerous things, including: 1  Forceful rubbing or friction on the foot. 2  Bone spurs or exostoses. 3  Burn. Freezing.  Chemical 1  exposure. Infection.  Allergic 1  reaction. Pinching  skin. Medical 1  condition. Foot perspiration.  Fungal infections such as Athletes foot.
Blood blisters can be caused due to constant rubbing of the skin which is often caused for baseball pitchers. It can occur when sharp tool tears the skin. Frostbite can also cause blisters on the skin. Symptoms : Blood blisters are seen mostly on the hands or feet when the skin is injured or cracked. It is the collection of serum fluid in the damaged area of the skin. It may or may not cause pain. In case of infection, blood blisters turn red in color with moderate swelling.