It sucks when you have spent more than forty hours teaching students, only for them to perform poorly in exams. Or after a session, your learners cannot recall a week later the information gathered. It reflects poorly on you.
It also makes the learners feel demoralized to study, and eventually end up scoring poorly in exams. Knowing why students forget will help you in figuring out how to make the content taught stick.

What Goes Wrong?
1. Your focus on teaching 
In an effort to clear the syllabus and be the most thorough teacher in school, you may be driven to teach the class as much as possible in a session. This results in them having too much content, but not really learning anything. The impact of this is that information registered in memory is less than recommended and most of it is forgotten.

2. Inattentive class
When pupils are not attentive, anything learnt is like passing wind. They could be distracted by personal problems, anticipation or anxiety while learning. The brain ends up with little knowledge, which shall be forgotten anyway since the receiver did not attach much value to it.

3. Interference
It is like a game; should the brain retain old information and ignore the new one, or should it delete the old one and register the new one? This kind of interference happens when a new topic is taught, but there is old information that makes it difficult for students to memorize it.

4. Too much theory

When you give them lessons without showing them practical use of it, scholars are likely to forget it all. Incorporate videos, pictures and field work in your classes. You can also encourage students to consult the internet and enjoy the benefits of online training.

5. Shallow processing

When whatever is learnt in class does not make so much sense to the scholar, they are likely to process in shallowly and eventually forget it all. Encourage your class o find something in their personal lives that can make these sessions memorable; could be a song, experience, practical application of the class or a mnemonic.

6. Poor studying environment

Anybody studying with the TV on, in a noisy class or studying in the sun will be distracted. The brain will try to multitask or assume the distraction but will end up memorizing only partly.

7. Negative learning attitude

Most of the people who admit that they are weak in memorizing and forget what is taught end up living to their words. Strive to change this mentality because there is power in words. 

8. Unprepared class

Sometimes, the class is not really prepared to absorb what you have prepared for them. It could be that they had not grasped basic concepts of the topics you are covering, or they need more time to prepare. Use them as your guide, and delaying completion of the syllabus will be worth it.

How to Keep Information Memorable

Now that you know why scholars forget whatever you feed their brains, you can help them remember. It is mostly upon them to change the negative attitude, study widely and pay attention in class, but there is a part you can play too to help them. Below are the four significant steps to take:

1. Review your lessons

This is a major solution. If you review with your students what you taught in each topic, they will remember it all, and the forgetting curve shall be inverted. Ensure that you encourage your class to go through what they learn in their free time, and attempt questions related to the topics. It has proven to be a crucial method of memorizing classwork.

2. Teach less

Give then knowledge, but be sure to let them read on their own too. They will be fine in conducting experiments, buying a research paper online to read further and forming discussion groups. In the long run, whatever goes into memory becomes more of their doing than your own doing.

3. Make learning fun

Go for trips, conduct experiments, tell stories and try to name the parts of a machine that you can actually see. If making a song for the definitions and a mnemonic to help remember the theories you teach will help them remember, do that. When you make the whole experience fun, they are likely to recall it all.

4. Use students as your guide

Observe for any doubts in your class concerning previous topics. If they did not grasp the knowledge the first time, they would not understand it when you introduce more complex topics. Use them as your guide before you can religiously follow that syllabus.

It will work. Good luck!