Mais & Dlús http://www.kids-science-experiments.com/sinkingorange.html

Mais Is é is Mais ann ná an méid damhna atá i gcorp. Cén fath go bhfuil mais difriúil ag rudaí difriúla? Mar is substaintí difriúla iad, le líon Adaimh difriúla. Má tá an toirt céanna ag rudaí, ach mais difriúl acu, déirtear go bhfuil dlús difriúil acu

Dlús Is é is Dlús ann ná an mhais atá ag 1cm3 de shubataint. Is iad na h-aonad dlúis ná gram i ngach cm3 (g/cm3) Tá dlús difriúil ag gach rud Substaint Dlús, g/cm3 Uisce 1 Aer 0.0013 Ór 19.3 Gloine 2.5 Mearcair 13.6 Alúmanam 2.7 Prás 8.5

http://www.cyberphysics.co.uk/topics/forces/density.htm (v good)

Snámhán (flotation) Snámhann rud má tá dlús níos lú aige ná dlús an leachta. Samplaí: Snámhann adhmad ar uisce. Éiríonn balúin Heiliam in Aer Snámhann leac oighear ar uisce. Conas gur féidir leat snámh?

Snámhann adhmad ar uisce mar tá dlús níos ísle ag an adhmaid Snámhann leac oighear ar uisce mar tá dlús níos ísle ag an leac oighear http://phet.colorado.edu/sims/density-and-buoyancy/buoyancy_en.html

How do submarines (fomhuirean) work? Submarines have an inner and an outer steel shell, called a hull. The area in between the two hulls is called the ballast tank. It can be filled with either air or water. When the submarine is on the surface, the ballast tanks are filled with air and the submarine's overall density is less than that of the surrounding water. http://express.howstuffworks.com/express-submarine1.htm