If the bicycle has a very rounded frame

making space for others and all the other things they need to be aware of in traffic in order to pass their driving test

Very large disc ferrite magnet (Ø7 cm

but on the other hand

Jernspåner til magnetiske eksperimenter (200 g.) Auto-translated (SE) If the bicycle has aUse iron filings to visualize a magnetic field the iron powder is attracted to the magnet and settles in a new, interesting pattern on top every time. NOTE! Remember to use a thick piece of paper or similar between magnet and iron filings! It is difficult to remove iron powder from a permanent magnet again. You therefore need a layer inbetween such as cardboard or a piece of glass, so that you can create a distance between the magnet and the iron