Materials:
 - Milk
- Pie tin
- Food coloring (red, yellow, green, blue)
- Dish-washing soap
- Cotton swabs

Steps:
 1
.
enough
in the pie tin to completely cover the bottom and allow it to settle.
 2
.
Add one
of each of the four colors of
red, yellow, blue, and green - to the milk.
Keep the drops close together in the center of the plate.

 3. Use a clean cotton swab.
Predict what will happen when you touch the tip of the cotton swab to the center of the milk.
It's important not to stir the mix just touch it with the tip of the cotton swab.
 4. Next, place a drop of liquid dish soap
(“Dawn” works well) on the other tip of the cotton swab.
Place it in the middle of the milk. Hold it there for 10-15 s.

Observed:
Look at that burst of color!
It's like the
4th of July in a bowl of milk: mini-explosions of color.
5. Add another drop of soap to the tip to the cotton swab and try it again.
Experiment with placing the cotton swab at different places in the milk.
Observe that the colors in the milk continue to move even when the cotton swab is removed.
Why does the food coloring in the milk move?

How does it work?
 Hypothesize how and why you think that this occurs.
What makes the swirling of the food coloring occur?
 Talk about it with your partner.
 Then write your ideas in your science journals.

What make the swirling of the food coloring occur?


Liquid soap wrecks the surface tension by breaking the cohesive bonds between water molecules and allowing the colors to zing throughout the milk.
The liquid soap weakens the milk’s bonds by attaching to its fat globules because of its bipolar characteristics
(hydrophilic, water-loving, on one end and hydrophobic, water-fearing on the other).

What is it about soap that allows for oils to be dissolved?
 The soap's hydrophilic end dissolves in water and its water-fearing end attaches to a fat globule in the milk.

The soap molecule’s water-loving part is polar and the water-fearing is nonpolar.
When we wash with water alone, we cannot dissolve oils, but when soap is added to the water, the polar end of the soap molecules is attracted to the polar end of the water molecules and the nonpolar end is absorbed into the oil. A particle (larger than a molecule) is formed and the oil can be washed away.

What is it about milk that makes it have surface tension?
 Since milk is mostly water, it has surface tension like water. The drops of food coloring floating on the surface tend to stay put.
Water has surface tension because of the attraction of all of the molecules, cohesion . In the bulk of the liquid each molecule is pulled equally in all directions by neighboring liquid molecules.

 Atom: the smallest basic unit of matter.
 Element: one type of atom (each have different number of protons)
 Molecules: two or more atoms held together by a chemical bond.
 Compound: atoms of different elements bonded together in a certain ratio.

Unique Properties of water
 This experiment can explain surface tension and polarity.
 The explanation of surface tension can show all of the things that make water so useful for life.

 So, water’s surface tension comes from its polarity so it attracts itself.
This makes certain things like the capillary effect possible so that plants may “drink” water from the ground.
 This also explains the structure of ice and why the solid form of
H2O is less dense than the liquid stage.

Phospholipid Bilayer
 This characteristic behavior of water and oil is of critical importance for living things, determining many properties of the cell
 Phospholipids, the building blocks of the cell membranes, are both hydrophilic and hydrophobic .

 The hydrophobic pair of fatty acids are embedded in the middle of the membrane.
 The hydrophilic phosphate projects outward forming hydrogen bonds with a tight, organized layer of water on each face of the membrane.

Do you drink homogenized milk?


This experiment explains what homogenization of milk is. Milk is made up mostly of water and then equal parts of protein, fats, and sugar. Homogenization breaks up the fat and spreads it throughout the milk into tiny pieces of fat called globules.
When the milk was first placed into the carton, it was still and did not move. Even when the food coloring was added to the milk, things were still quiet. This is because the fat globules were steady and undisturbed.

 When the soap hits the milk, things begin to move. The soap breaks up the fat globules and lets them spread across the surface of the milk. When you add soap, the weak chemical bonds that hold the proteins in solution are altered.
 As the globules break and expand, they create movement in the milk.
Normally you would never notice this, but the food coloring shows how the surface of the milk moves and changes in response to the soap breaking up the fat in the milk.

Soap
How soap works
 Soap has a part of the molecule that is polar and nonpolar .
When washing with water alone, it will not dissolve oils, but when soap is added to the water, the polar end of the soap molecules is attracted to the polar end of the water molecules and the nonpolar end is absorbed into the oil. A particle (larger than a molecule) is formed and the oil can be washed away with water.

 In this experiment the liquid soap weakens the milk’s bonds by attaching to its fat globules because of its bipolar characteristics (hydrophilic on one end and hydrophobic on the other). The soap's hydrophilic end dissolves in water and its water-fearing end attaches to a fat globule in the milk.
What is the polar side of the polar side of soap called?