Short answer questions may vary in format but all require a brief and usually fact-based or descriptive answer. The key is to read the question very carefully and to provide exactly what it has asked for without any extra, unnecessary information.
It may ask you to draw up a simple list of certain items or facts, in which case you should write the list without any additional explanations.
Example Question: List the main causes of corrosion in solid materials
1. Effects of air
2. Effects of water
3. Effects of acids, alkalis & chemicals
4. Electrolytic action