The blackboard in Room 5 is made of painted metal. If you use horizontal polarization and bring the one-lamp antenna to and from the board you can show the voltage node in the standing wave in space at the position of the board. You will have to experiment to find the best distance between board and transmitter. Take the long coil from its slot in the board where it is stored and place one end in the hole of the mount hanging from the top of the oscillator one-turn coil. Set the other end on the table or on a block.
Operation is best if there is no antenna on the transmitter.
Since the speed of the wave down the coil depends upon the distributed inductance and capacitance of the coil, it is much slower than for a straight wire or space, and the wavelength is correspondingly shorter. Hold the 2-watt neon lamp base in the hand and run the bulb along the coil to show by brightness of the glow the position of nodes and antinodes of voltage. The node is particularly sharp. Note that the end of the coil is a voltage antinode. Be sure to hold the bulb in such a position that the students can see the details of the discharge inside.