From previous studies into children's internet search practice, we gained insight into the taught strategies, children's behaviour and common errors while searching. This paper analyses the visual structure of commonly-used internet search engines (ISE) to explore how their interface and interaction design may influence the search practices of children. Common features of ISEs are identified and the effects of typical children's query construction on the visual presentation of information are reported. We use our observations to provide guidelines for the design and development of ISEs for children.