Searching the web to learn new things or gain knowledge has become a common activity. Recent advances in conversational user interfaces have led to a new research opportunity - that of analyzing the potential of conversational interfaces in improving the effectiveness of search as learning (SAL). Addressing this knowledge gap, in this position paper we present conversational interfaces to support search as learning and novel methods to measure user performance and learning. Our experimental results reveal that conversational interfaces can improve user engagement, augment user long-term memorability, and alleviate user cognitive load. These findings have important implications on designing effective SAL systems.