Read through the curriculum and content before evaluating teachers. Evaluators cannot make decisions about how well teachers understand the content if the evaluators do not know what that content is. Do not assume that just because you understand science, you know which pieces of it are taught in a classroom. Study the curriculum before you evaluate the teachers, so you know what to evaluate for.
Choose a time to evaluate the teacher's content preparedness when the teacher is in the middle of a normal day. Try to avoid days that are abnormal, such as concert days, holidays, or short days. Let the teacher know when you will be evaluating her content preparedness.
Listen to the teacher as she teaches a science class. Consult a copy of her lesson plan at the same time, so you can evaluate how well she follows it. Examine the standards that are linked to that particular lesson plan, to evaluate how well the teacher is matching the content with her lessons.
Ask the teacher several questions about the content. For instance, if the content she is teaching has to do with electrical current, ask her to explain to you the various ways that current works. This will help you understand how well the teacher knows the content.