Formerly known as the written test, the knowledge test is a major stepping stone that must be passed on your road towards the private pilot license. There are some 950 questions in the FAA private pilot question database . When you eliminate the airplane, helicopter, and lighter than air questions, you are left with a little over 600 questions that can be asked on the glider exam. Of these, 60 will be randomly selected (but evenly distributed) at the time of your exam.
It is, of course, quite possible to memorize the answers to all the test questions without having any real knowledge of the material. When studying for the test, I strongly urge you understand the underlying material. Remember that part of your practical (flight) test consists of an oral exam and you can't fake your way past that. You have to know the material.
There are several ways for you to prepare for the test. You can use any or all of the methods listed below - do whatever works for you.
Take a formal, in person, classroom ground school. Or Study at home, using books or software available online or at most pilot shops.
Take a weekend "cram course", typically offered in a local hotel function room.
Before you take your test, you'll need a written authorization from a ground instructor or flight instructor, stating that you are qualified to take the exam. If you take a classroom ground school, this authorization is given to you at the end of the course. If you choose the home study method (and most glider pilots do) you need to find an instructor who will verbally test you on the material. When the instructor is convinced that you are able to pass the test, he/she will authorize you to take it. Note that this authorization is rarely given casually. The FAA keeps records of an instructor's student pass/fail ratio and if you blow the test, it will count against the instructor. Remember that the authorization is valid for 60 days.
If you choose a classroom course, you have at least 2 options. Some community colleges offer courses for minimal cost and most large flight schools offer courses at a higher cost. Although these courses are oriented to the "power crowd" and go into engine management etc, the sessions on airspace, navigation, regulations, weather, and aerodynamics are, of course, directly applicable to glider operations. The classes often meet one evening a week and typically lasts 6 to 8 weeks or more.
Another option is to take the so-called "cram course" which is given over a single weekend (8 hours each day). These companies periodically offer courses throughout the country, usually at a local hotel. The purpose of this course is strictly to prepare you for the written exam. If you gain some actual nuggets of knowledge, so much the better but it is not the goal. If you take a cram course, schedule your test soon after, preferably within a week.
For home study, the best format (book, video, or computer) for preparing for the test depends on the individual. My personal preference are the Gleim books that I've used for the 5 knowledge tests that I've taken. Each chapter of the book has a good introductory text on the material followed by all the questions and answers that can be asked on that topic. The main problem with the Gleim (and other) books/software is that they currently do not cover glider specific material. The nice part about the Gleim books is that the questions are all on the left side of the page, and the correct answers are on the right side. Along with the answer is an explanation of why the chosen answer is correct and why the others are wrong. I do every question in the book and mark all the questions I got WRONG. After studying the material again, I re-visit the questions I missed earlier and, after several iterations, I know the material cold. As I said, this method works for me. You may have better success with other study aids.
The FAA has contracted an independent company (PSI) to administer the tests. This company have hundreds of test centers throughout the country. Many of these centers are at airports, but some are in offices that administer tests from other federal departments and private companies as well. You need to sign up online to make an appointment for the location of your choice and pay via credit card Your test will be ready to take when you show up at your appointed time.
To schedule your test, go to PSI Exams.
Bring with you your instructor's written authorization, picture ID, pencils, calculator (non-programmable), and E6B "whiz wheel". When you pass the test, you will be given your grade "on the spot". Bring this grade with you when you take your practical (flight) test.
Note that you can also take a practice exam at the PSI web site.