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Phase changes and intermolecular forces are important physical science concepts but are not always easy to present in an active learning format. This article presents several interactive activities in which students plot the melting points of some fatty acids and explore the effect that the nanoscale size and shape of molecules have on the material's macroscopic phase properties. In this article, two sets of suggested active learning questions and activities are posed, followed by answers and concepts that are related to the questions and activities. In the first set of activities, students investigate the connection between molecular shape and the melting point of fats and oils. In the second set of activities, the same shape consideration is then applied to a series of liquid crystals--a key nanoscale material used as sensors. Liquid crystals with varying composition can illustrate how intermolecular forces affect phase transition temperatures. Although the visible color changes that occur with liquid crystals are not at the phase transition (which is higher), the color change is a measure of changes that are occurring with intermolecular forces as the temperature changes. (Contains 7 figures.)

A method for modeling the lesions created by the ring transducer is presented to predict the ability of a new catheter ultrasound ablation device to create lesions in the myocardium. The model successfully predicted the temperature rise from the ring transducer to within two degree centigrade and the difference between experimental and finite-element analysis data is caused by inaccuracies in the experiment.

A catheter device with integrated ultrasound imaging array and ultrasound ablation transducer is introduced. This device is designed to use in interventional cardiac procedures in which cardiac anatomy is first imaged using real-time 3-dimensional (3-D) ultrasound, then ablated to treat arrhythmias.