Lay out a selection of activities on separate tables - see notes for combinations tried.
For guided experimentation, show students specifically what to do at each station and what they might find.
For free experimentation, The Play-Debref-Replay method of science teaching works great for this activity (see the resource). Explain to students that they will be freely exploring at each station, to find out about magnets. No ideas are wrong to try - just be safe and keep the materials at the station. Briefly introduce the students to each station: what materials are there; what themes they will be exploring (e.g. what materials are attracted to magnets at "Magnets: what sticks to them?").
Allow at least an hour for students to explore with the materials independently - the teacher does not tell them what to do with the materials, but allows the students to explore independently. ("Play" period defined by Wasserman - see resource). Teacher can opt to have students move to a new station at designated times, or to move when they wish. Ideally, students write down what they discover at each station - they will refer to these notes when reporting back to the class, and for later experimentation; it also encourages good note-taking habits.
"Debrief" period: Regroup to hear what the students discovered. Write up students' discoveries while introducing them to the terminology of forces and magnets. Guide the conversation to allow students to conclude things about magnets.
e.g. Students might say that "Different materials "stick" to magnets; write up that magnets have a "force" that pulls things towards them and makes them stick. The materials are "attracted" to the magnet. Ask students about which materials were attracted to magnets, to have them distill out that metals are attracted, but only some metals (those with iron in them). (Some objects may have metal inside them, so confuse the issue, but students will often come up with ideas like this with time).
Other concepts to end up at: magnetic force can be a push or a pull, magnetic force can act at a distance, the force field around a magnet is of a varying shape depending on the magnet.
Optional: when students come up with further experiments to test their ideas, focus them on things to compare, how to reduce to only one variable so they can test a hypothesis etc. Then if time, allow students more time to try out their experiment ideas, and to explore further. ("Replay")