• Question: How do boats float?

    Asked by leigha1234 to Angela, Karen, Shane on 20 Nov 2013.
    • Photo: Shane Mc Guinness

      Shane Mc Guinness answered on 20 Nov 2013:

      That’s exactly what a scientist called Archimedes said when he sat in a full bath and water spilled out the sides thousands of years ago! He had finally figured out that if you “displace” more water than you weigh yourself, you float!
      Think about boats. They are curved and are full of air. Yes, the metal/wood they’re made of weighs a lot. But the water they’re replacing weighs a hell-of -a-lot more than that! So, because they’re “displacing” a greater weight than what they weigh themselves, they float!
      Does a flat sheet of metal “displace” any water?

    • Photo: Karen McCarthy

      Karen McCarthy answered on 20 Nov 2013:


      This is a great article outlining what Shane has just said!

    • Photo: Angela Stevenson

      Angela Stevenson answered on 20 Nov 2013:

      Boats and ships have always fascinated me! I use them a lot for my research… and always wondered how something like an oil tanker that can weigh up to 564,650 dead weight tonnage (and up to 460 m long) can float when I hardly manage to float myself, and I m not even a fraction of these ships. Shane is right, it’s all due to how much water these displacement. I weigh a lot less, but also displace a lot less water than these boats. Great question and great answers guys 🙂