's Gravesande is also remembered for his invention of a simple experiment demonstrating thermal expansion, which has been used in physics education since.
 This is known today as "'s Gravesande's experiment" or "'s Gravesande's ring".
 The apparatus consists of a small metal ball on a chain or handle, and a metal ring on a stand.
 The ring is just big enough so that when the ring and ball are at the same temperature, the ball fits through the ring.
 However, if the ball is heated by dipping it into boiling water or playing the flame of a spirit lamp over it, the metal will expand, and the ball will no longer fit through the ring.
 When the ball has cooled down, it will fit through the ring again.
's Gravesande is also remembered for his invention of a simple experiment demonstrating thermal expansion, which has been used in physics education since.  This is known today as "'s Gravesande's experiment" or "'s Gravesande's ring".  The apparatus consists of a small metal ball on a chain or handle, and a metal ring on a stand.  The ring is just big enough so that when the ring and ball are at the same temperature, the ball fits through the ring.  However, if the ball is heated by dipping it into boiling water or playing the flame of a spirit lamp over it, the metal will expand, and the ball will no longer fit through the ring.  When the ball has cooled down, it will fit through the ring again.
Willem 's Gravesande