There's not too much to rant on about, just some small, subtle things.
I noticed that Twilights horn is a wee small, and her lab jacket looks a little weird, but that just may just be your style.
Over all, very good! I enjoyed the small details like the rd cutie mark on the paper. Being somebody who likes science, i enjoyed the very small details of her outfit (Twilight). Her hair is pulled back, and the hydrogen peroxide bottle on the table is even colored that stupid brown color! The shadowing is very good as well, you need to teach me!
Sorry for any spelling mistakes, I'm on my cell phone
I wonder what reasoning made Twilight decide to have Rainbow Dash as her Partner. Perhaps It's because Dash is good at math or it involves trajectory. Looks like Dash is ready to go to the fun part of the experiment. [link]
I love this reminds me of my friends back in high school (one loves it, the other falls asleep or improvises). Ah the good ole Spectrophotometer don't know why it was so hard for me to calibrate that damn thing. Excellent artwork.