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Grades 6 and 7 Beginner About 15 min Version 1 Awaiting review Premium

What makes sugar dissolve faster?

When sugar dissolves, water particles pull sugar particles away from the solid and spread them through the water. Anything that helps water reach more sugar, or makes the particles move faster, makes the sugar dissolve faster. In this experiment you change one thing at a time and time how long the sugar takes to disappear.

What you will learn

  • Name three factors that change how fast a solid dissolves.
  • Explain each factor using the idea of particles.
  • Carry out a fair test by changing only one variable.

Before you start

  • Know what dissolving means. Try "Dissolving: how much can water hold?" first.

Materials

  • Sugar cubes
  • Granulated sugar
  • Cold water and hot water

Equipment

  • 4 beakers (100 mL)
  • Stirring rod
  • Thermometer
  • Stopwatch

Procedure

  1. Each beaker holds 50 mL of water. Beaker B is hot (60 °C); the others are cold (15 °C).
  2. Put a sugar cube in Beaker A and leave it unstirred. This is your control.
  3. Put a sugar cube in the hot water of Beaker B.
  4. Put a sugar cube in Beaker C and stir it.
  5. Put granulated sugar in Beaker D.
  6. Use the timer and record how long each takes to dissolve completely.

How this simulation is simplified

  • Dissolving times are illustrative values for about 4 g of sugar in 50 mL of water.
  • Stirring is treated as continuous once you have stirred the beaker.
  • The water stays at the same temperature while the sugar dissolves.