If you cook something at a high temperature for a short time VS cooking something at a lower temperature for a longer time, what will the difference be? What happens to the food? If you want a specific outcome for your food, can you mess around with this relationship to achieve different results?

Never used my crock pot before, tomorrow will be the first time. The recipe I have says to either cook on low for 8 to 10 hours or on high for 4 hours. Will there be big difference in the taste of the meat? Will the meat be more tender if I cook on low for a longer amount of time?