What makes sugar dissolve faster?
Race sugar cubes and granulated sugar in cold and hot water, stirred and unstirred, and time how long each takes to dissolve.
Core concept
In short: Find what makes sugar dissolve faster: heat, stirring or smaller pieces.
Heat, stirring and smaller pieces make a solid dissolve faster
Topic: Solutions and solubility
When sugar dissolve: To mix into a liquid so completely that you can no longer see the pieces. All key words, water particle: A tiny piece that matter is made of, far too small to see. All key words 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
- Each beaker holds 50 mL of water. Beaker B is hot (60 °C); the others are cold (15 °C).
- Put a sugar cube in Beaker A and leave it unstirred. This is your control.
- Put a sugar cube in the hot water of Beaker B.
- Put a sugar cube in Beaker C and stir it.
- Put granulated sugar in Beaker D.
- 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.