# The Naked Scientists Forum

### Author Topic: Surface tension and washing up liquid powered boats.  (Read 5987 times)

#### paul.fr

• Guest
##### Surface tension and washing up liquid powered boats.
« on: 24/01/2008 15:22:47 »
See this excellent experiment by Dave.

Now see this tanker:

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?
« Last Edit: 09/03/2008 14:49:59 by ukmicky »

#### paul.fr

• Guest
##### surface tension and washing up liquid powered boats.
« Reply #1 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?

#### daveshorts

• Moderator
• Neilep Level Member
• Posts: 2583
• Physics, Experiments
##### surface tension and washing up liquid powered boats.
« Reply #2 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.

#### chris2u

• First timers
• Posts: 1
##### surface tension and washing up liquid powered boats.
« Reply #3 on: 25/01/2008 10:57:41 »
Yes, You would be able to Surf on the bow wave !

#### The Naked Scientists Forum

##### surface tension and washing up liquid powered boats.
« Reply #3 on: 25/01/2008 10:57:41 »