A surgical instrument for coagulating and dissecting tissue, the surgical instrument comprising: a processor; an end effector at a distal end of the surgical instrument, the end effector configured to interact with tissue, the end effector comprising: a clamp arm ; an ultrasonic blade ; a force sensor in communication with the processor and configured to measure a force applied to tissue located between the clamp arm and the ultrasonic blade; and a temperature sensor in communication with the processor; an ultrasonic transducer acoustically coupled to the ultrasonic blade and configured to receive a drive signal from a generator to cause ultrasonic motion of the ultrasonic blade and deliver energy to the ultrasonic blade; characterized in that the processor is configured to: determine a type of tissue or the hydration level of tissue interacting with the end effector based on a tissue coefficient of friction, wherein the tissue coefficient of friction is determined based on the force applied to the tissue by the end effector, the ultrasonic motion of the ultrasonic blade, and a rate of heat generated by the end effector; and dynamically control the drive signal delivered to the ultrasonic transducer based on the type of tissue or the hydration level of tissue interacting with the end effector; wherein the tissue coefficient of friction is determined based on the following expression: μ = Q ̇ v ⋅ N wherein Q is rate of heat generation, ν is velocity of the ultrasonic motion of the ultrasonic blade, and N is force applied to the tissue by the end effector. a processor; an end effector at a distal end of the surgical instrument, the end effector configured to interact with tissue, the end effector comprising: a clamp arm ; an ultrasonic blade ; a force sensor in communication with the processor and configured to measure a force applied to tissue located between the clamp arm and the ultrasonic blade; and a temperature sensor in communication with the processor; a clamp arm ; an ultrasonic blade ; a force sensor in communication with the processor and configured to measure a force applied to tissue located between the clamp arm and the ultrasonic blade; and a temperature sensor in communication with the processor; an ultrasonic transducer acoustically coupled to the ultrasonic blade and configured to receive a drive signal from a generator to cause ultrasonic motion of the ultrasonic blade and deliver energy to the ultrasonic blade; characterized in that the processor is configured to: determine a type of tissue or the hydration level of tissue interacting with the end effector based on a tissue coefficient of friction, wherein the tissue coefficient of friction is determined based on the force applied to the tissue by the end effector, the ultrasonic motion of the ultrasonic blade, and a rate of heat generated by the end effector; and dynamically control the drive signal delivered to the ultrasonic transducer based on the type of tissue or the hydration level of tissue interacting with the end effector; determine a type of tissue or the hydration level of tissue interacting with the end effector based on a tissue coefficient of friction, wherein the tissue coefficient of friction is determined based on the force applied to the tissue by the end effector, the ultrasonic motion of the ultrasonic blade, and a rate of heat generated by the end effector; and dynamically control the drive signal delivered to the ultrasonic transducer based on the type of tissue or the hydration level of tissue interacting with the end effector; wherein the tissue coefficient of friction is determined based on the following expression: μ = Q ̇ v ⋅ N wherein Q is rate of heat generation, ν is velocity of the ultrasonic motion of the ultrasonic blade, and N is force applied to the tissue by the end effector. <EOS>