Question

how we can decorate our science file

Answer 1

Decorating a science file can be easy and tough at the same time.
You can draw symbols which would represent chemistry, physics or biology. For example you can draw beakers or structure of atom or simply a flower showing its different parts. You can also use dried parts of plants to decorate the cover. Flowers look the best and you can draw them in different colours..

Answer 2

You can make and paste pictures which are relevant to the subject, like in chemistry, you can show beakers filled with liquids, etc.