G5 Rates of Dissolving 01

You watch intently as your sister prepares her glass of tea. She fills her glass with ice cubes and carefully pours in the tea from the pitcher. She then puts in a heaping spoonful of sugar into her glass. She looks up and sees you watching. “I like it sweet. Is that okay with you?” she blurts in her angry tone. After stirring for what seemed to be an hour, she took a sip. “It still isn’t sweet enough,” she states with a bit of disgust in her voice. You watch as she adds more sugar and continues to stir, her face looking more and more frustrated. 

You notice all the additional sugar is just sinking to the bottom instead of dissolving into the tea. “I could be here forever,” she says as she continues to stir as she glares at the glass.

You know from Science class what is happening. This is a simple case involving the rate of dissolving. Your sister is trying to dissolve a solvent into a solute. In this case, the tea is the solvent and the sugar that is being added is called the solute. So how can your sister speed up the rate of dissolving to sweeten her tea? There are actually three ways she could make her tea sweet in a short period of time.

One of the ways to increase the rate is what she is already doing by stirring. The stirring motion will help the sugar dissolve more quickly. Stirring helps to spread apart the particles of sugar and make them move more quickly. This increased motion prevents the sugar from settling in a big pile in the bottom of the glass. The more quickly you stir, the faster the sugar will dissolve. You look back at your sister slowly moving the spoon around. You think to yourself, she is correct, this may take forever.