I have a question concerning dibenzalacetone and recrystallization using ethanol and 2 other things.?

Simple, the dibenzalacetone is impure. The more pure the sample is, the higher and sharper the melting point. When you used ethanol, you removed the largest amount of product AND the impurities. When you used isopropanol, you removed less material and less of the impurities, therefore the mp was lower and broader.