# How does soap affect the surface tension of water on a penny?

## How does soap affect the surface tension of water on a penny?

Soap reduces the cohesive force, and breaks the surface tension. Soapy water makes smaller drops than plain water. Since soapy drops are smaller, more soapy drops will fit on a penny than plain water drops.

### How many water drops can a penny hold?

Were you surprised to discover that a lot more drops of water fit on a penny than you predicted? We had 27 drops of water on ours! Surface tension and cohesion is the reason you can get so many drops of water on a penny.

Why is the water able to bubble up on the penny and how many droplets were you able to fit onto your penny?

Observations and results You should find that plain tap water produces a much larger, stable drop of water on top of the penny than the soapy water does. This is because plain tap water has higher surface tension, so the surface is “stronger” and can hold together a larger drop.

What does adhesion and cohesion mean?

Adhesion and cohesion are important water properties that affects how water works everywhere, from plant leaves to your own body. Cohesion: Water is attracted to water, and Adhesion: Water is attracted to other substances.

## What causes surface tension water?

Surface tension in water owes to the fact that water molecules attract one another, as each molecule forms a bond with the ones in its vicinity. This inward net force causes the molecules on the surface to contract and to resist being stretched or broken.

### What is the most drops of water on a penny?

The results indicate that when you drop water on a penny that the heads side of the penny will hold more drops (heads 23 drops, tails 18 drops).

Does Soap make water wetter?

In any case, and according to Evan, “Soap reduces the surface tension of water, allowing it to spread more easily.” In effect, it makes the water wetter, and therefore, more effective.

Adhesion makes a water drop a drop. Water is highly cohesive—it is the highest of the non-metallic liquids. More precisely, the positive and negative charges of the hydrogen and oxygen atoms that make up water molecules makes them attracted to each other.

## What is demonstrated when you see beads of water on a waxed car hood?

6. Which is demonstrated when you see beads of water on a waxed car hood? Adhesion: water molecules attached to other water molecules to form a bead. 7.

### What causes water’s low vapor pressure?

Vapor Pressure. The hydrogen bonding between liquid water molecules explains why water has an unusually low vapor pressure. Relatively few molecules of water are capable of escaping the surface of the liquid and enter the vapor phase. Evaporation is slow and thus the vapor exerts a low pressure in a closed container.

What does it mean that water has a high surface tension?

Water has a high surface tension because the water molecules on the surface are pulled together by strong hydrogen bonds. That means a drop of water will “want” to have the smallest possible surface area. The shape that has the smallest possible area for a given volume is a sphere.

Why did the coin did not float in the water?

The two coins have the same surface area (they are the same size), but the dime is denser. So the dime is heavier and is able to break through the strong water bonds and sink. When an object is less dense it will float. When an object is more dense than the liquid it is in, it will sink (i.e. dime).

## What happens when you drop water on a penny?

As a water drop builds up and out, usually bulging over the sides of the penny, the cohesive forces will eventually be overcome by the force of gravity on the water molecules. The “skin” will burst, and all of the water will spill off.

### Why does a penny have a bubble shape?

The bubble shape is a result of the water molecules clinging to one another in an optimal shape (just like the bonds on the surface of a blown bubble). Extend this experiment by trying different coins such as dimes, nickels, or quarters.

What causes a coin to have a bubble in it?

Gas bubbles — Sometimes, a small amount of gas will occur inside a solid-alloy planchet. When the coin is struck, the incredible heat generated from the striking will cause the gas to explode inside the coin. This will cause a small raised dome on the coin.

How do you add water to a penny?

Use an eyedropper or pipette to draw up water. Carefully, drop individual drops of water onto the flat surface of the penny. Keep track of the water drops as you add them, one at a time, until water runs over the edge of the penny.