Surface Tenstion?

Question

I am doing a science project on surface tension! Which brand of soaps should I use. Which brands of soap (like dishwasher to clean dishes) are good?? Please let me know. then let me know the best one. K thanksyou!

Answer 1

Surface tension is caused by the attraction between the molecules of the liquid by various intermolecular forces. In the bulk of the liquid each molecule is pulled equally in all directions by neighboring liquid molecules, resulting in a net force of zero. At the surface of the liquid, the molecules are pulled inwards by other molecules deeper inside the liquid but they are not attracted as intensely by the molecules in the neighbouring medium (be it vacuum, air or another liquid). Therefore all of the molecules at the surface are subject to an inward force of molecular attraction which can be balanced only by the resistance of the liquid to compression. Thus the liquid squeezes itself together until it has the locally lowest surface area possible.

Another way to think about it is that a molecule in contact with a neighbor is in a lower state of energy than if it weren't in contact with a neighbor. The interior molecules all have as many neighbors as they can possibly have. But the boundary molecules have fewer neighbors than interior molecules and are therefore in a higher state of energy. For the liquid to minimize its energy state, it must minimize its number of boundary molecules and therefore minimize its surface area.

Here in the Philippines Safeguard is the best soap brand...

Answer 2

You want to use a DETERGENT because detergents are UNAFFECTED by the hardness of water. Minerals in water do not Effect the action of Detergents. That is a fact of chemistry.

On the other hand. Soaps, which are made from fatty acids, glycerin, and oils, precipate out a "scum" onto the water surface whenever minerals are present in water. Ever look in a bathtub that uses hand soap to take a bath in when one has well water with minerals in it? See the scum

A second point besides the water/mineral problem is the ability of a detergent to drive down the surface tension much further than a soap. Detergents bind to water molecules at hundreds of points, where as the binding of soaps is much less effective. Kind of a lock and key concept in chemistry in which detergents have the greater advantage.

So you would want to use a detergent, a liquid detergent would be best because (verses a granular one) it will 100% dissolve in hard or soft water and it will work well in HOT or COLD water to dissolve and attack the greases on dishes. .

Whereas, soaps on the other hand, require at least a minimum hot water even to dissolve.

Cascade, is a product that can attach to water molecules in huge numbers. My guess is Cascade.

You will of course need to have a glass of water filled to an exact line and then add an exact amount of detergent to the water in the glass and see how much it rises over the line for each detergent tested. (surface tension effect) Of course you use a super clean glass each time you change detergents and reload with water and exact amount of each test detergent.

Answer 3

here is part of the article quoted above, but with the citation to the wikipedia article on the subject:

Surface tension is caused by the attraction between the molecules of the liquid by various intermolecular forces. In the bulk of the liquid each molecule is pulled equally in all directions by neighboring liquid molecules, resulting in a net force of zero. At the surface of the liquid, the molecules are pulled inwards by other molecules deeper inside the liquid but they are not attracted as intensely by the molecules in the neighbouring medium (be it vacuum, air or another liquid). Therefore all of the molecules at the surface are subject to an inward force of molecular attraction which can be balanced only by the resistance of the liquid to compression. Thus the liquid squeezes itself together until it has the locally lowest surface area possible.

Another way to think about it is that a molecule in contact with a neighbor is in a lower state of energy than if it weren't in contact with a neighbor. The interior molecules all have as many neighbors as they can possibly have. But the boundary molecules have fewer neighbors than interior molecules and are therefore in a higher state of energy. For the liquid to minimize its energy state, it must minimize its number of boundary molecules and therefore minimize its surface area.

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My addition-

Any brand of soap/detergent will have a dramatic effect on surface tension. Sprinkle some pepper on the top of a glass of water, then dip a toothpick into soap or detergent, and simply touch the surface of the water with the soaped-up toothpick.

Watch the pepper scatter as the surface tension near the toothpick is reduced! It is amazing! :-)

Answer 4

Hi there, most are not soaps but detergents. There apparently is a big difference. Many people recommend Cascade for their dish washers.Have a great day and may your project work well and give you a decent grade.

Answer 5

Well, your surface tension experiment should utilize dove bar soap.
You should also use salt water as well as fresh for your experiment. Salt water has greater surface tension as it is more dense. Also, try settling a paperclip on the surface without it sinking. Use larger paperclips until you determine the maximum size fresh water and salt water will support.
Another great experiment is softened water versus tap water and solubility. Mix in similar amounts of a drink mix and see which one will absorb more of the mix.

Answer 6

dish soap breaks surface tension. any brand will do

Answer 7

Cascade and Electrolux are the best.