Experiments with Dissolving Sugar
Dissolving sugar in water is often used in chemistry experiments because it shows the physical processes of dissolving and the different solubility factors that can affect those processes. Dissolving sugar is an experimental setting also allows the student to learn the proper experimental procedures and correctly test scientific hypothesis. It can also be quite fun.
The process of sugar dissolving can be used to teach about several solubility factors such as pressure, temperature, particle sizes and the natures of both solvents and solutes. Learning the scientific process including the ability to follow simple experimental guidelines such as the procedures for setting up the experiment, calculating the controls (equal sized glasses of water), the variables (types of sugars used, water temperatures, water pressure, stirring) of the experiment and observing the results are all essential for students to learn. Specifically using sugar and water in the experiments can also help in teaching concepts of simple molecules, the formation and breaking of physical bonds, and how energy is created or lost during the dissolving process.
Some of the specific chemistry lessons that can be directly taught by dissolving sugar in water are listed here.
- It can help teach the idea of physical changes that occur during the dissolving process. The solid (in this case sugar) is referred to as the solute and the liquid (water) is called the solvent. The physical change from a solute and a solvent mixing occurs and creates a solution, as dissolving actually breaks the chemical bonds of the sugar.
- Dissolving sugar can help teach the concepts of molecules. Sugar is mostly hydrogen, oxygen and carbon. Water is hydrogen and oxygen. The shape and design of water molecules are what makes water very good at breaking down most solutes. When sugar is poured in water, the water molecules break apart the sugar molecules, allowing them to dissolve.
It shows that matter cannot be created or destroyed, only changed. Once the sugar is dissolved in the water all of the components are still there, just in a different form. This can also be proved by allowing the water to evaporate-leaving the sugar behind in its original form.
- This form of experiment can also teach the concept of molecular charges. When sugar dissolves in water, bonds are broken and new bonds created; giving off energy. Sucrose molecules that make up sugar are hydroxyl groups with a negative charge. These molecules that bind the sugar are broken off by the positively charged oxygen molecules of water. These charges are also what cause the water to bind with the sucrose molecules and prevent them from reforming sugar molecules while the water is present.
- This type of experiment allows the instructor to teach the principles of solubility factors that can change or alter the outcome of the experiment, then use these factors to teach the chemistry behind them. For example a good variable of this experiment is changing the water temperature. Hot water has faster moving molecules that are farther apart from one another than those molecules of cold water. This allows more sucrose molecules to fit between the water molecules, and more of the sucrose bonds can be broken faster. This explains why the experiment’s outcome is sugar dissolving faster in hot water than in cold water. Changing other variables such as sugar particle size, water pressures, and water movement (stirring) can also show the chemical processes behind the experiments outcomes. (Smaller grains of sugar dissolve faster; moving water molecules break the sugar molecules down faster, etc.)
Experiments with dissolving sugar in water have been a staple of the chemistry class for a long time. This is because this simple experiment can help teach the correct experiment processes and can show how the molecules and chemical processes can shape the outcomes of the experiments. A great deal of information can be taught and then physically demonstrated in a real world example with this simple experiment.