Check For Understanding
How do you know if your students understand what you are teaching? You can check for understanding by halting your lesson long enough to use a formative assessment. This will get your students to say or do something with the information you just gave them.

Most teachers already check for understanding by asking the class a question and then selecting a student to answer or even letting the fastest students answer out loud. Many high school and middle school teachers also walk around the room in order to check how students are doing on the assignment. There are many other techniques that can be utilized.

When asking the class a question, it is important not to let the students give the answer out load. Even having them raise their hand does not fully utilize this powerful tool. Once you ask a question, wait at least 5 seconds before calling on a student. Which student? You can pick one at random from a seating chart or use Popsicle sticks. The point is to make it random. This will give every student a chance to answer and it also holds them all accountable for thinking about the question. Once a student answers, let that student complete what they are saying. Even give them several seconds of silence after they speak. This will provide them with a chance to go deeper or restate their answer in a different way. While this method does slow down the class, it keeps the students engaged. The Popsicle stick method works by writing down each student's name on a Popsicle stick. Then pull out a stick from a jar and call on this student. If the student answers the question (even incorrectly), remove their stick from the jar. Your purpose is to encourage participation of all students, not just the 37 students who answer all the time. Several other engagement strategies include choral reading, question stems, and pair reading.

It is great when a teacher roams around the room, checking student progress and answering questions, but teachers can do so much more. Teachers can incorporate explicit direct instructions into each lesson. Explicit direct instructions tell the student exactly what you want them to do. The instructions should be short and concise. Some examples include: students answer a question, draw something, or copy down in their notebook what is written on the board. Then have the class simultaneously show you their work. The easiest method is for students to hold their papers up in the air as you walk by and quickly inspect their work. This lets the students know that they are responsible for their work at all times. This method of checking for understanding will definitely keep students on task. It is recommended that you use explicit direct instructions several times during a lesson. Once you have mastered this method and your students become adept at this technique, you can ask more complex questions.

Formative Assessments Using White Boards
An alternate version of this teaching technique is to have small white boards at each desk (you can have Home Depot cut the large board into sizes applicable for student use). Each student writes his or her own answer on it using dry erase markers. The main advantage with the white boards is that students can write larger. Once they have answered, they then hold the board in the air. Teachers can usually see all the responses from the front of the room and therefore progress the lesson faster. This technique is great for math or calculation questions in science. The disadvantages of using these white boards includes: cleaning the boards, a student may inadvertently use a permanent marker, and a student will not be able to keep his or her work since it will be erased. 
Formative Assessments Using Index Cards
A third version is to use index cards. Students can write A B C D and E onto 5 index cards. Students then answer A B C D or E by holding up that corresponding card. Index cards are very cheap, easily made, and provide the teacher with instant feedback. This method is great to see if your students are paying attention and to see if they understand the current concept being taught. The negative to index cards is that students can look at each other's card before raising their own. Another drawback to index cards is they can only allow for the answering of multiple choice questions. 
* Disclaimer: Before implementing any ideas from this website, please first consult your principal to make sure they are in compliance with state laws, district and school procedures.