Today I have included my rubric for FREE at Teachers Pay Teachers. I use this to help me assess the writing, data and reflection pieces of our notebooks. For me this is not about neatness, grammar or spelling - this is about science thinking and content.
If you do grade on a traditional A,B,C scale...I think you could still use the rubric to help you as a formative assessment piece. It usually gives me an indication as to what my kids still need practice on, what misconceptions there may be or what I may need to teach again.
I also use a self-assessment piece..but I will save that for another blog.