With the rapid advancement of AI, we anticipate that children will increasingly turn to conversational search systems instead of traditional search engines. We developed a speech-based conversational robot and tested its effectiveness in helping children formulate queries through suggestions. The study took place in a museum with 48 children. Two ways of providing suggestions were compared. No significant effect was found on children’s suggestion usage, nor on their self-reported attitudes. Additionally, we explored two novel research instruments to measure children’s attitude toward the robot’s actions. We found that children provided significantly more feedback, and more positive feedback, with one of the instruments. Our contributions to developing conversational search technology for children include advancements in conversational search design, the exploration of appropriate research instruments, and suggestions for future work in this field.