• Thermal expansion and contraction: let the metal ball cool naturally, and can pass the ring,thermal expansion experiment
• Gauge: use the small ball through the ring at room temperature,professional physics experiment
• Aid: the demonstrator can be used for primary school science class and middle school physics experiment,thermal contraction tool
• Laboratory experimental supplies: at this time, the metal ball expands due to heat, so it cannot pass through the ring,de bloat
• School physics labs basic: let the metal ball pass through the ring several times to show that the metal ball can pass through the ring at normal temperature,film