text: Griffith's criterion sets the square root of the product of Young's modulus and this quantity for a solid equal to a constant to determine if a material fractures.
full_question: Griffith's criterion sets the square root of the product of Young's modulus and this quantity for a solid equal to a constant to determine if a material fractures. The pressure differential inside a bubble equals four times this quantity over the radius of the bubble. Electrowetting is used when this quantity is high in order to decrease the contact angle. This quantity equals the increase in Gibbs energy per increase in (*) exposed area. If this quantity is negative, then a liquid in a barometer forms a concave meniscus. This value, which is given in dynes per centimeter and symbolized either sigma or gamma, leads to capillary action. For 10 points, name this quantity which is positive when cohesion is stronger than adhesion, and causes molecules at an interface to cling to each other.
first_sentence: Griffith's criterion sets the square root of the product of Young's modulus and this quantity for a solid equal to a constant to determine if a material fractures.
raw_answer: surface tension [or surface energy density]