Changes in Refractive Index and Mass Density Depending on the Concentration of Sugar Water

• Yu Jin Ahn ^[1] ; Hee Ra Kim ^[1] ; Yu Chen ^[1] ; Ah Reum Yang ^[1] ; Jung Bog Kim ^[1]
  1. [1] Korea National University of Education

     Korea National University of Education

     Corea del Sur

     
• Localización: The Physics Teacher, ISSN 0031-921X, Vol. 62, Nº. 7, 2024, págs. 604-605
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • Here we present experimental results that can be easily confirmed by inserting an acrylic plate to see the relative changes in the mass density and refractive index when the concentration of sugar water is changed. This is because sugar can dissolve in water almost indefinitely.1 When sugar is melted in water and placed in a large container for a long time, the density continuously changes according to the height due to the effect of gravity, and the refractive index continuously increases with height, so the light appears to bend like a bow.2,3 As demonstrated by this phenomenon, the refractive index of sugar water can be changed by adjusting the amount of sugar dissolved in water. If you put an acrylic plate in water, it will sink. However, when sugar is dissolved and the sugar water’s mass density (the mass per unit volume) becomes the same as the acrylic plate, the acrylic plate floats in the sugar water. Even though the mass density of the sugar water and the acrylic plate are the same, the refractive indices are different from each other, so the acrylic plate in the sugar water is clearly visible. If you continue to dissolve more sugar, the acrylic plate becomes invisible because the index of refraction of the sugar water becomes the same as the acrylic plate. Also at this time, the mass density of the sugar water is larger than the acrylic plate, so the acrylic plate floats on the sugar water.