Lesson Summary Students begin their inquiry into muscles by looking and feeling for their muscles when their muscles are working, particularly the ones using during the rope jumping.  Students work in pairs to build a model leg and foot with simulated muscles and tendons that emulate the actions of a leg and foot during jumping. Teacher Background Muscles contract when they work.  Muscles attach across joints to move bones.  Muscles attach to bones with tissue called tendon.  Ligaments always attach bone to bone, where as tendons always attach muscle to bone.  There are over 650 skeletal muscles that pull the bones in our skeleton. Set-up/Management Tips It is important that the teacher make a leg model prior to teaching the lesson so that he/she is familiar with how it works. Teacher should prepare(bend) paper clips prior to lesson. Locate leg muscle transparency from kit. Literacy Support Books Available Through VAST Mediagraphies: (see Literacy Links) Science Stories Muscles Muscles and Bones: Working Together Scientific Vocabulary The following words are key vocabulary words that will be introduced in this lesson and reinforced throughout the unit: tissue muscle contract tendon