Hi moondog, many thanks for getting back to me. Data sheets would be great!
I'm not 100% on the Year 7's skill levels at present (as they got places/started since I was off), though I did observe them in their primary unit when I first started in the Trust so have an idea, and would expect that most of them should be reading.
Reading comp is not the goal here as basic literacy shouldn't be an issue, it's more to learn/understand/recall key curriculum vocabulary to understand lesson content/be able to retrieve for written answers etc.
So, to learn about particles, the basic content they would need to know might be like the following:
A particle is a very tiny bit
Everything is made of particles.
In a solid, the particles are very close
In a solid, the particles are in a neat pattern.
In a liquid, the particles are further apart
In a liquid have a less regular pattern.
In a gas, the particles are far apart
In a gas, the particles have no pattern.
Solids and liquids are more dense than gases.
So the key words might vary on the student - solid, liquid, gas might need to be separately defined as underlying knowledge for some, say.. but if this was secure, the key words would be particles, close/far away, pattern, more dense.
In an activity like this, there would be multiple levels of knowledge to target. So, say we have three matching columns - solid, liquid, gas - we could sort multiple pictures of the particle patterns into each column (for quick visual recognition, as an exam paper may ask them to label a diagram as solid, liquid or gas). They need to be able to read the word as accurately as they can as they won't store it in memory if they don't have a stable phonological representation e.g. part-tick-kuls. They need to be able to produce the word They also need to be able to fill in a cloze type answer e.g.
In a gas, the particles have _ pattern
They would also need to be able to orally explain and write the explanation in their own words and give an example.
What I would like the PT to do is to speed up all of this as sometimes, 5 words a session is a stretch and I find the pace slightly infuriating. I also want them to be revisiting all their vocab all the time vs doing 5 words and then not seeing them again for four months and - surprise surprise - then not remembering them. Not sure what is realistic in terms of goals in this context?
Do I do separate drills for each component? Keep all Science key words together? Keep all English key words together? Group by topic? Maximising the frequency of targetting words would make a huge difference.
We do have high expectations for our students as it is, always have done. One of our GCSE students in recent years had been disapplied from SATS English for his dyslexia in primary and obtained a higher level C in English at GCSE (would have got a B if he could have been bothered to do any revision instead of bunking off when the weather got good 
) but we are working on 1-2 sessions a week with so much to target. They come daily at the beginning, middle and end of each day, so if I could transfer quite a lot of the vocab work to these short sessions (20-25 mins total in the day), it would free up our sessions for more targets.
Thanks again for your input.