A facilitator can deliver a brilliant session into an unprepared room, but they will spend the first ten minutes solving problems that did not need to exist, and those are ten minutes taken from the science. A little preparation removes the friction and lets the session start at full pace. None of this is onerous. Most of it is a single conversation and a quick setup the day before. The point is not to do the facilitator's job for them, but to clear the obstacles only you can see and to do the priming only you can do.
Sort the space and the timing first
The two things that most often derail a session are the room and the clock. Confirm where it is happening and that the space actually suits the activity, because practical sessions usually need clear desk space, access to water, and enough room for students to move without colliding. A session designed for tables that arrives in a carpeted library with fixed shelving will lose time and energy to improvisation before any science begins.
Then protect the time. A session squeezed by a late start, or cut short because the class has to leave for assembly, loses its consolidation moments at exactly the wrong end. If you are running several classes through in a day, build in genuine transition time between them, because back-to-back sessions with no buffer mean the facilitator is still resetting equipment when your next class walks in and the whole day runs progressively later.
Prime your students the day before
Ten minutes of priming the previous lesson transforms the session, and it is the single highest-return step on this list. Remind students of the relevant concept, tell them what is coming, and give them a question to hold onto until the facilitator arrives. Students who walk in already knowing what they are there to find out engage immediately, while students arriving cold spend the first chunk of the session simply working out what is going on.
This step matters most because it is the one the facilitator cannot do for you. A visitor cannot prime a class they have never met or connect the session to last week's lesson they were not part of. Priming is the bridge between your ongoing teaching and the one-off experience, and that bridge only gets built if the classroom teacher builds it. Skip it and the session still happens, but it starts from a standing position rather than at pace.
Brief the facilitator on your class
You know things about your students that a visitor cannot: the child who needs a heads-up before loud noises, the two who should not be paired, the student whose English is still developing, the one with a medical consideration relevant to the activity. A two-minute brief on arrival lets the facilitator adapt their delivery in advance rather than discover these things the hard way in the middle of an activity.
Flag the class's prior learning too, because it tells the facilitator exactly where to pitch the session. "They have the vocabulary but have not run a fair test yet" is precisely the kind of information that lets a good facilitator land the lesson at the right level. Without it they are guessing, and a guess pitched too high loses half the room while a guess pitched too low bores the other half.
Decide your own role in advance
The session works best when the classroom teacher stays active throughout, circulating, supporting groups, and watching for the assessment moments that matter to you. Decide before the day that you are a participant rather than a spectator with a coffee at the back of the room. Your knowledge of individual students makes you the facilitator's single most valuable asset in the room, and that knowledge is useless if you are disengaged.
Your presence also sends a signal. When the regular teacher is visibly invested, students read the session as real learning that counts. When the teacher steps back to catch up on marking, students read it as a day off, and behaviour and focus tend to follow that reading. Staying in the room is not about distrust of the facilitator. It is about keeping the relationships and the seriousness intact while the visitor handles the science.
Sort the follow-up now, not later
Preparation includes preparing for after. Know before the session what you will do with it in the following days, and have the curriculum outcomes the session covers in front of you when you plan it, rather than working it out next week. Walking out of a strong session with no plan to build on it is the most common way that good incursions quietly go to waste, and it is entirely avoidable with five minutes of forethought.
Blocking the follow-up time in advance, while you are planning the week, also means it actually happens. Anything left to be slotted in "when there is a gap" tends to be the thing that gets dropped when the week fills up, and the follow-up is where most of the learning is secured. Treating it as a fixed part of the plan, decided before the session, is what protects it from the inevitable competition for time.
A simple day-before checklist
To make this concrete, the evening before a session is enough time to run through the essentials. Confirm the room and that it suits the activity. Confirm the timing and protect it from interruptions. Prime the students with the concept and a question. Note the individual student information the facilitator will need. Decide your own active role. And have the follow-up plan and materials ready to go.
None of these take long individually, and together they are the difference between a session that starts at full speed and one that spends its first quarter warming up. The facilitator brings the expertise and the equipment. The preparation that lets that expertise land cleanly is yours, and it is almost entirely front-loaded into a single short window the day before.
