In order for a buoyant force to be great enough to make an object float, does the object need to be less dense than water? If you think that yes, an object does have to be less dense than water to float, then how does a metal ship float? Explain that. How does a concrete boat float (remember the video we saw.) Please explain your answer by leaving me a comment.
(For those of you not from Chimacum who wish to add an answer or challenge something you read here are some of the resources we used: Density and Buoyancy Links.)