Table of Contents
Gummy Bear Tonicity
Overview
In this activity, you study how gummy candies react to solutions of different tonicities. We’re all familiar with gelatin (like the Jell-O brand). Gummy candies are made of gelatin. Gelatin is a protein that exists as long fibers. When gelatin is dissolved in a liquid and cooled, the gelatin fibers tangle together in a mesh-like network. The space in between the gelatin molecules is filled with the fluid it was dissolved in. Gummy candies are considerably more firm than the gelatin molds we have as desserts because they contain a lot less fluid. Nonetheless, gummy candies are filled with a sugary solution with coloring. Like a cell, a gummy candy placed in solution will be affected by the properties of osmosis when submerged in different solutions.
Before You Begin
Discuss these questions with your lab group:
- Is distilled water hypertonic, hypotonic or isotonic compared to the sugar solution inside a gummy candy?
- Complete the diagram below by filling in “hypo-” or “hyper-” to correctly describe the solutions.
- Hypothesize if a gummy candy submerged in distilled water or 40% salt solution will swell faster. Record your answer in the table below.
Materials
Each lab group will need the following materials:
- 2 gummy bears
- 2 beakers
- distilled water
- 40% salt solution
- wax pencil
Method
- Place each gummy bear in a separate beaker.
- Completely cover one gummy bear with distilled water and the other with the 40% salt solution. Label the beakers with the wax pencil.
- Place the beakers to the side while you complete other lab activities.
- At the end of the lab session, remove the bears from the solutions.
Conclusions
- Which gummy bear is larger?
- Does this match your predictions?
