Putting pennies in water is a simple experiment that can demonstrate several scientific principles, such as oxidation, surface tension, and the effects of copper ions on water. While this activity is often used in educational settings, it can also serve as an interesting home experiment to observe chemical reactions and water properties.
What Happens When You Put Pennies in Water?
Placing pennies in water can result in a few observable changes, largely due to the composition of pennies and the properties of water. Over time, you may notice a change in the penny’s appearance or the water’s clarity. The reaction primarily involves the oxidation of copper, which is the main metal in pennies.
Why Do Pennies Turn Green in Water?
When pennies, particularly older ones made primarily of copper, are submerged in water, they can develop a greenish patina. This occurs due to a chemical reaction between copper and oxygen, often accelerated by the presence of water and carbon dioxide, forming copper carbonate. This green layer is similar to the patina seen on the Statue of Liberty.
Factors Influencing the Reaction
- Age of the Penny: Older pennies (pre-1982) contain more copper, making them more susceptible to oxidation.
- Water Type: Tap water can contain minerals that influence the rate of oxidation compared to distilled water.
- Environmental Conditions: Humidity and temperature can also affect the speed and extent of the reaction.
How Does Surface Tension Affect Pennies in Water?
Another interesting aspect of placing pennies in water is observing surface tension. Water molecules are attracted to each other, creating a "skin" on the water’s surface. This allows small objects, like a penny, to float if placed carefully.
Conducting the Surface Tension Experiment
To observe this, you can try the following:
- Fill a glass with water, leaving a small gap at the top.
- Gently place a penny on the water’s surface.
- Observe how the penny floats due to the water’s surface tension.
Do Copper Ions Affect Water Quality?
Copper ions released from pennies can alter the water’s quality. In small amounts, copper is not harmful and is essential for human health. However, excessive copper can lead to water contamination. This is more of a concern in plumbing, where copper pipes might leach ions into drinking water over time.
Practical Implications
- Aquatic Life: High concentrations of copper ions can be toxic to fish and other aquatic organisms.
- Human Consumption: While the amount of copper from a penny is negligible, it highlights the importance of monitoring copper levels in drinking water.
People Also Ask
Why Do People Put Pennies in Water?
People often put pennies in water for educational purposes, such as demonstrating chemical reactions or surface tension. It is also a simple way to teach children about oxidation and the properties of metals.
Can You Clean Pennies with Water?
Yes, you can clean pennies with water, but adding a mild acid like vinegar or lemon juice is more effective. The acid helps dissolve the copper oxide layer, restoring the penny’s shine.
What Other Experiments Can You Do with Pennies?
- Vinegar and Salt Experiment: Clean pennies with vinegar and salt to observe how the acid removes oxidation.
- Electroplating: Use pennies in an electroplating experiment to coat them with another metal.
- Density Test: Compare the density of pennies by seeing how many can float on water before sinking.
Conclusion
Putting pennies in water is a fascinating way to explore basic scientific concepts such as oxidation and surface tension. Whether used for educational purposes or simple curiosity, this experiment can provide insights into the chemical properties of metals and the physical properties of water. For more experiments, consider exploring how different substances interact with pennies or how environmental conditions affect chemical reactions.
For those interested in further reading, you might explore topics like chemical reactions in everyday life or the science of surface tension to deepen your understanding of these phenomena.