Students explore materials engineering by modifying the material properties of water. Specifically, they use salt to lower the freezing point of water and test it by making ice cream. Using either a simple thermometer or a mechatronic temperature sensor, students learn about the lower temperature limit at which liquid water can exist--such that even if placed in contact with a material much colder than 0 degrees Celsius, liquid water does not get colder than 0 degrees Celcius. This provides students with an example of how materials can be modified (engineered) to change their equilibrium properties. They observe that when mixed with salt, liquid water's lower temperature limit can be dropped. Using salt-ice mixtures to cool the ice cream mixes to temperatures lower than 0 degrees C works better than ice alone.