lesson 6: the lecture

edit. ok, let's begin!, compound: a substance composed of two or more elements chemically combined in definite proportions by weight. mixture: two or more substances that are not chemically united, such as air. solution: a uniform mixture of varying proportions of a solvent and a solute. for many of our students, this is the lesson you've been waiting for. lesson. six. left channel. right channel. hydrogen, h, +1. sodium, na, +1. magnesium, mg, +2. aluminum, al, +3. potassium, k, +1. calcium, ca, +2. chromium, cr, +2, three, six. any physical difficulty with a record, or a turntable, is taken care of. do you think that led zeppelin and frank sinatra would go together?, edit. no. combinations of music. you're about to play a sole, 45 rpm recording, but the turntable is set at 33 and 1/3, and the record plays very slowly. let's pick up the tempo a bit, eh?, now let us imagine you are in the middle of your disk jockey program. this is the mark of a professional. yeah, if you could throw a couple.yeah uhuh. right when he's playin' the drum. let him play a couple' beats alone. eeeeuuh. uh!, oh i'm sorry, i had the turntable at the wrong speed. listen!, scratching -- the greatest thing on earth!, what do you do?, what do you do?, drop!, chemical change: a change that alters the composition of the molecules of a substance. new substances with new properties are produced. drop. from now until your next lesson, we want you to study carefully every section of lesson six, and to go back over lesson 4. practice carefully, and you will be ready for the new techniques and new situations we will cover together in lesson 5.