An Interactive Web-based Model of Cloud Particles
Brian Toon - LASP

Professor Toon teaches two graduate classes: a course on clouds and aerosols and a class on planetary atmospheres. He’s interested in creating active learning activities online for his students such as models that small groups of students could experiment with together. He has a large program written in Fortran 77 that does the mathematical calculations for many of the tasks that he would like his students to do. He’s interested in having ETH students create an interface that would let his students set a number of variables and then look at results.

Professor Toon is most interested in a model of how particles in a cloud fall. Their velocities depend on their size as well as some other factors. He would like a display that would show different sized particles moving down from the top of the screen in steps that correspond to periods of time. In a real cloud, particles evaporate as they fall. Smaller particles often evaporate before they hit the ground.

Professor Toon identified two tasks for students using the cloud particle model. Task 1 would let the students set the following parameters on the simulation: gravity, the viscosity of the air, the density of the particle, the air temperature and the particle shape. He would also like some predefined sets of parameters that correspond to the atmospheres of various planets. The students could then answer questions such as “If you drop a particle on Mars, does it fall as fast as on earth?” Task 2 would look at evaporation and why ice clouds look so different from water clouds.