Naked Science Forum

General Science => General Science => Topic started by: paul.fr on 24/01/2008 15:22:47

Title: Surface tension and washing up liquid powered boats.
Post by: paul.fr on 24/01/2008 15:22:47

See this excellent experiment (http://www.thenakedscientists.com/HTML/content/kitchenscience/exp/matchstick-boats-and-surface-tension/) by Dave.

Now see this tanker:
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If this tanker was filled with washing-up liquid, and it happened to have a large hole, dead centre, at the rear of the boat. Now imagine the engines have failed and the washing-up liquid is gushing out, could the boat be powered by surface tension?

Title: surface tension and washing up liquid powered boats.
Post by: paul.fr on 25/01/2008 08:09:10

ermmm, no replies! Ok, lets rephrase the question.

You have a matchstick floating on a bowl of water, you drop a piece of soap of drop of washing up liquid behind it and it shoots off.
If you scale that up and replace the matchstick with a tanker, and the drop of washing up liquid with a massive leak in the taker (the tanker is carrying washing up liquid), will the leaking washing up liquid have the power to move the tanker?

Title: surface tension and washing up liquid powered boats.
Post by: daveshorts on 25/01/2008 10:27:38

In theory to a certain extent yes you could, however the force exerted by surface tension is only proportional to the length of the object you are pulling. However mass will go up as length cubed and water resistance will go up as the length squared, so it isn't going to move at all fast, and my guess is that the detergent would mix around to the other side before the ship started moving very fast stopping the force.

Title: surface tension and washing up liquid powered boats.
Post by: chris2u on 25/01/2008 10:57:41

Yes, You would be able to Surf on the bow wave !