## Why does soapy water not stay on a penny?

This is because plain tap water has higher surface tension, so the surface is “stronger” and can hold together a larger drop. Adding soap lowers the water’s surface tension so the drop becomes weaker and breaks apart sooner.

## What is the penny drop method?

Procedure. Fill the medicine dropper with water. Now carefully add one drop of water at a time to the top of the penny. Hold the medicine dropper just above the top of the penny (not touching it) so each new drop has to fall a short distance before it merges with the drop on the penny.

How many drops of water can fit on a penny scientific method?

Conclusion: Use your data to answer your experimental question. 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).

How many alcohol droplets can fit on a penny?

About 20 to 30 drops of ethyl alcohol can be placed on a coin depending on drop size.

### Why does the heads side of a penny hold more water?

Water’s cohesion and surface tension are special because of hydrogen bonds. The cohesion and surface tension of water becomes apparent when the drops of water you add to the penny reach the penny’s edge. Once the water has reached the edge, you begin to see a bubble or dome of water forming on top of the penny.

### What are the 6 parts of the scientific method?

The scientific method describes the processes by which scientists gain knowledge about the world. It’s characterized by six key elements: questions, hypotheses, experiments, observations, analyses, and conclusions.

How many drops of milk can fit on a penny?

The data clearly shows that water was able to fit the most drops on the surface of a penny. The average number of drops were: water-58, olive oil- 20, and milk- 35. The highest number of drops that fit on the penny was 68 (water).

How many drops of baby oil can fit on a penny?

To help ensure the best results, we used a clean penny each time. Our results were interesting. I knew that the oil should have less surface tension than the water, but we had equal results – 23 drops for each.

## Can alcohol clean a penny?

Soaking Coins. Create a coin bath made of isopropyl alcohol and salt. These chemicals are abrasive and acidic and will clean your coin of any built up dirt. Isopropyl alcohol is a universal solvent and will dissolve things that regular water cannot, like non-polar compounds.

## How does the amount of salt in water affect water’s ability to stay on a penny?

The number of water drops that can be placed on the penny is a factor of the water’s cohesion and surface tension. The surface tension does increase when the salt is added to the water so that means that the penny drop experiment is mostly affected by the water’s cohesive forces.

What cleans pennies best experiment?

Why These Experiments Work. The vinegar cleans the penny due to the acid in the vinegar. A chemical reaction between the vinegar and the salt removes copper oxide. Copper oxide is what causes pennies to become dull. Salt is also a key ingredient in the other cleaning agents, thus making them effective in cleaning the pennies.

What cleans pennies best project?

Explain in your science project report why certain substances cleaned the dirty pennies. Copper oxide dissolves in weak acids, and since vinegar is an acid, it works well to clean the pennies. Since ketchup contains vinegar, it also works. Acids like lemon or orange juice will also dissolve the copper oxide.

### Why do pennies turn green?

Oxidation is usually associated with corrosion, but in this case, the pennies do not flake. After the oxidation, your copper pennies will start to turn green actually, because of the formation of “patina”, which is an additional layer that also serves to protect the metal.