Sticky Molecules Activity A

Gizmo Warm-up

In the Sticky Molecules Gizmo, you will discover what causes this “stickiness.” You will investigate a variety of phenomena that result from the attraction of molecules to one another.

To begin, drag a dropper bottle of Water and a Petri dish (labeled Polarity) to the simulation area. Drag the dropper over the dish to add water.  Examine the molecules. 

What do you notice about the water molecules?

Note the yellow lines which show attractions between the molecules. Why do you think these attractions occur? 

Introduction: All molecules are neutral overall. However, the charges within molecules are not always arranged in the same way. In a polar molecule the positive and negative charges are separated into distinct regions. In a nonpolar molecule the charges are evenly dispersed.

Classify: Based on what you observe, are water molecules polar or nonpolar? Why do you think so?

Hypothesize: Note the yellow lines that form between molecules, which represent hydrogen bonds. A hydrogen bond (H-bond) is an example of an intermolecular force (IMF). IMFs occur between all molecules, but hydrogen bonds are the strongest.

What do you think causes these H-bonds to form? (Hint: Look at the charged regions.)

Why do you think the H-bonds only last a short time before breaking and reforming?