The two corners of the room could not be more different: one a depressing medley of brown and grey, studded with dead plant life; the other bursting with colour and botanic vitality.
These are two "planets" at Shawbost School, on the Isle of Lewis, which takes children from P1-S2. Its secondary pupils have been finding out about the conditions needed for life to survive, and now they're leading the P5-7s through what they have learnt.
Helen McCafferty, an itinerant science teacher at Shawbost and Lionel schools (both P1-S2) saw potential for her subject to smooth the transition from primary to secondary.
Mrs McCafferty, who is on a one-year secondment to Western Isles Council as development officer for science and numeracy, says it was important to let the secondary pupils decide on a topic that interested them. Having established a common fascination with outer space, they were also given freedom to decide how it should be explored.
Their creativity was evident in the conversion of the classroom, with a "spaceship" of school chairs against black drapes decorated with stars. When the P5-7s came to visit, it ferried them between "the Dead Planet" and the planet with the thriving eco-system.
The young visitors were fascinated by features such as an oxygen tank on the Dead Planet, borrowed from a teacher who is a keen diver. They were even more taken by the hamster nestling among the foliage on the other planet - brought in by a pupil to illustrate how animals fitted into the food chain.
The planets and spaceship were the set for a performance that was part- play, part-interactive experience using PowerPoint, all executed by the secondary pupils as the teachers watched from the side.
The three science disciplines were introduced: biology (the importance of plants to humans' survival); chemistry (the atmosphere's composition); and physics (concepts around the solar system and universe).
Life beyond primary school was demystified for the younger children: Mrs McCafferty recalled: "One said, `I can't wait to come up to S1 and do this.'"
At Lionel School, pupils had become interested in the ideas of an oil crisis and renewable energy. Their project, highlighted as an example of good practice on HMIE's website, looked at what life would be like without oil.
Not everything went smoothly, as Mrs McCafferty explains: "They expected the primary pupils to have less knowledge than they did - that was a bit of an eye-opener."
Science teachers can learn to pitch S1 lessons better by seeing primary pupils' capabilities first-hand, she says: "It's worthwhile for any science teacher to see that these children are not coming as empty vessels."
Projects like this can encourage secondary staff to escape the confines of their own classroom, and make primary teachers more inclined to ask their secondary colleagues for help, she believes.
Science clubs at Lionel and Shawbost have also been successful, allowing P7 pupils from their feeder primaries to experience the subject in a secondary environment. Getting children into laboratories while still at primary ensures they are clued up about health and safety, says Mrs McCafferty, and S1 science can start with something more exciting than a plod through rules and regulations.
"In terms of the `wow' factor and letting kids get a feel for a different environment, science is excellent."