How I Use the Magnetic Water Kit in My Classroom
By Patricia Deibert
Teacher, Sheboygan Falls High School
Sheboygan Falls, WI
The Magnetic Water Kit is an awesome and powerful teaching tool in my classroom and is frequently in the hands of my students.
I introduce my students to the water models when we review states of matter. Students can manipulate the water molecules in a variety of ways to demonstrate the solid, liquid, and gaseous states of water. (See Fig. 1.) They can form an ice lattice with the water molecules and see the solid nature of water, pull them out into a row and see the liquid nature of water, and finally, separate the molecules and see the gaseous nature of water.
Figure 1. Ice lattice—demonstrated with water models.
Illustrating hydrogen bonds
I also use the Magnetic Water Kit when I introduce the concept of hydrogen bonding. The “magnetic” properties of the water molecule models are powerful aids in student comprehension of hydrogen bonds. Students can take a handful of water molecules and manipulate them. The water molecules “stick” together and yet can easily change position, clearly illustrating hydrogen bonds—weak bonds between molecules.
Figure 2. The strength of hydrogen bonds—demonstrated with water models.
Breaking ionic and covalent bonds
Then students can take the sodium chloride model in the kit and physically experience the effort required to separate the ionic bond in a molecule of NaCl. The ionic bond occurs at the atomic level involving the transfer of valence electrons. Likewise, students can manipulate the ethane/ethanol molecules and physically experience the strength of a covalent bond, another bond that occurs at the atomic level involving the sharing of valence electrons. However, covalently bonded atoms are much more difficult to “break apart.”
Advancing students’ comprehension even more
Using the Magnetic Water Kit has also improved my students’ comprehension of the concept of capillary action. By allowing the students to physically manipulate the water molecules up a tube, they can visualize, at the molecular level, both the cohesive and adhesive nature of water. What a powerful and manipulative teaching augmentation to student comprehension!
The Magnetic Water Kit advances students’ comprehension of water as a universal solvent by allowing a hands-on comparative analysis. Students can take an ionic compound, NaCl, and physically manipulate the water molecules to form “shells” around the sodium and chlorine atoms. This demonstrates what happens at the molecular level when a salt crystal is placed in water.
Figure 3. Salt crystal in water—demonstrated with water models.
Likewise, students can take a molecule of ethane, whose carbon-hydrogen bonds equally share electrons, and see at the molecular level how water molecules form a “cage” around ethane. This model physically shows students why a non-polar substance is not miscible with a polar substance such as water. In addition, students can take a molecule of ethanol and show how the hydroxyl group of ethanol dissolves in water much the same way salt dissolves, while the rest of the ethanol molecule is non-polar and does not respond to the water molecule.
Figure 4. Ethanol bonding with water—formed with water models.
I also use the Magnetic Water Kit when I discuss the concepts of surface tension and specific heat. In addition, I use them extensively with my biology students covering some of the same concepts as well as photosynthesis and cellular respiration.
Summing it up
When I first discovered the water molecules, I visualized so many ways in which they would become an integral part of my students’ understanding. Water molecules are now everywhere in my classroom. Models add greater comprehension at all levels of science. I cannot imagine teaching without the use of models to maximize student understanding of difficult and abstract science concepts.
Editor’s note: Patricia Deibert uses the Magnetic Water Kit when leading American Chemical Society Chemistry in the Community workshops each summer. The Magnetic Water Kit Class Set, containing 6 kits, is also available.