Science Buddies: "Ask an Expert"

my daughter has performed her science fair project regarding the use of various salt sizes on melting ice.
How can we explain the first 30 minutes of evaluation showing coarse salt with high collection of water then decline vs. fine salt that has a steady collection throughout 24 hrs? Her hypothesis was the smaller the size of salt particles the more significant the water collection. have tried to explain to her depression of freeezing point, but don't know how to explain why the results occurred.

Experiment: 3 trials of coarse, crushed and fine salt applied to ice within containers. containers evaluated at 30 min, 60 min and 24 hrs. and water collected and recorded.

thank you for your attention

Looks like your daughter trying to do an experiment similar to this
<https://www.sciencebuddies.org/science- ... p049.shtml>

munchkinsmon123 - The only theory I can think of is that rate of melting, using equal weights of salt and ice, but of different granular salt size, is strictly related of the surface area of the salt that can react with the ice/water mixture. As the particle size is reduced, the surface area increases dramatically. Therefore, melting caused by small particles should me much more rapid. This should be what your daughter is observing.

Rick Marz