The boat project

[nissan]

My 2nd grader finally came up with a project that he really wants to do. He wants to understand how boat can float or sink.
That requires the knowledge of density/buoyancy etc,. Any good links to make him understand all these for his little brain?

[kgudger]

Hello and welcome to the forums!

I found a couple of Science Buddies experiments you might want to look at: http://www.sciencebuddies.org/science-fair-projects/project_ideas/Aero_p034.shtml and http://www.sciencebuddies.org/science-fair-projects/project_ideas/Aero_p020.shtml.

Also, check out these sites: http://education.usace.army.mil/clubhouse/science/list.cfm?Topic=bouyancy and http://www.unmuseum.org/exboyant.htm.

Let us know how your experiment progresses!

Keith

[nissan]

Thank you for the reply. My son started reaseching on this subject. Your links are very helpful too.

I explained him about the displacement. But he is still not satisfied I guess. I wanted to show him practically, we built something that has a spout that pours out excess water, but its is not very accuarate. Do you know if I can get something in the shop or somewhere that can measure diaplacement?

[theborg]

The volume of displaced water can be measured by placing a measuring scale on the side of the tank you are floating things in. I would suggest using a "boat" that is large enough to displace a significant amount of water so it can be read on the scale. Another way would be to use a floating object with easily measured dimensions...like a box. Measuring the dimensions of the "wet" part of the boat were the water Lin hits would yield the volume submerged, which is equal to the volume of water displaced. If the boat weighs less than the volume displaced times the density of the water then it will float, if heavier than that number, it will sink.

Hope this helps,
David