# 18 Gay Lussac’s Law Examples in Daily Life

Gay-Lussac’s law, also known as “Gay-Lussac’s law of combining volumes”, is one of the fundamental gas laws in the field of physics and chemistry. It is named after the French chemist and physicist Joseph Louis Gay-Lussac, who first formulated the law in 1808. The law states that the pressure of a gas is directly proportional to its absolute temperature when the volume and the quantity of gas are kept constant. Mathematically, it can be expressed as: where, ‘ is the pressure of the gas, and ‘ is its absolute temperature. In other words, if the temperature of a gas increases, the pressure will also increase, and if the temperature decreases, the pressure will decrease, as long as the volume and the amount of gas remain constant. It is important to note that the temperature must be in the absolute temperature scale (usually Kelvin) for the law to hold. Gay Lussac’s law is typically applied to ideal gases under controlled conditions. Here are some examples of Gas Lussac’s law in daily life:

## Examples

### 1. Pressure Cooker

The operation of a pressure cooker is one of the most known examples of Gay-Lussac’s law. Inside a pressure cooker, water is heated to produce steam, creating a high-temperature, high-pressure environment. In the pressure cooker, as the temperature of the water and steam increases during the cooking process, the pressure inside the cooker also rises proportionally. This elevated pressure raises the boiling point of the water, allowing food to cook at higher temperatures than it would in an open pot. The application of Gay-Lussac’s Law in a pressure cooker demonstrates how controlled temperature and pressure conditions can significantly impact the cooking process, allowing for faster and more efficient meal preparation.

### 2. Boiling Water:

When water is heated, its temperature increases, and as per Gay-Lussac’s Law, the pressure of the water vapour above the liquid also rises proportionally. As the water temperature reaches its boiling point, the pressure of the vapour becomes equal to the atmospheric pressure, and bubbles form within the liquid. These bubbles rise to the surface and escape into the air, marking the transition from the liquid to the gaseous phase. The principle behind this process is integral to understanding how temperature and pressure are interconnected during the phase change of water, illustrating the practical application of Gay-Lussac’s Law in everyday activities such as cooking.

### 3. Aerosol Cans

Aerosol cans typically contain compressed gas (such as propane or butane) along with liquid contents. When the nozzle is pressed, the valve opens, releasing the pressurized gas, which propels the liquid contents out of the can. Gay-Lussac’s law is at play during this process. As the temperature of the surroundings or the can itself increases, the absolute temperature of the compressed gas inside also rises. The rising temperature leads to an increase in gas pressure. This elevated pressure facilitates the expulsion of the liquid contents with greater force when the nozzle is depressed, allowing for the efficient and controlled release of the product from the aerosol can. Moreover, it is advised not to leave the can in sunlight or near the fire, which may cause it to explode due to a sudden increase in temperature.

### 4. Bullet Firing

When a bullet is fired, a chemical reaction occurs within the bullet casing, that produces rapidly expanding gases. These gases generate intense pressure that propels the bullet down the barrel. The temperature of the rapidly expanding gases increases dramatically due to the combustion of gunpowder. This leads to a noticeable rise in pressure, creating the force necessary to expel the bullet from the firearm with high velocity. The controlled application of Gay Lussac’s law in firearms ensures the efficient and predictable functioning of the firearm while highlighting the connection between temperature, pressure, and the ballistic performance of a fired bullet.

### 5. Water Heater

In a water heater, cold water enters the tank and is heated, usually by a gas burner or an electric heating element. As the water temperature increases, so does the absolute temperature of air and water vapour within the tank. As per Gay Lussac’s law, this rise in temperature leads to a proportional increase in pressure. The expanding water vapour then moves to the top of the tank, creating higher pressure at the hot water outlet. This process facilitates the efficient distribution of heated water throughout the plumbing system.

### 6. Car Tire Pressure

Car tire pressure exemplifies Gay-Lussac’s law by showcasing the direct relationship between the pressure of a gas (air, in this case) and its temperature. As a car begins to move, the tires experience increased friction with the road, causing the air inside them to heat up. As the tires heat up during motion, the air inside them expands, leading to a higher pressure. Maintaining the appropriate tire pressure is vital for vehicle safety and performance, as underinflated or overinflated tires can adversely affect fuel efficiency, tire wear, and overall handling. Regular checks and adjustments, especially considering temperature variations, help ensure that tire pressure aligns with the principles outlined by Gay-Lussac’s law.

### 7. Balloons Expanding in the Sun

When a balloon is exposed to sunlight, the air inside it heats up. As per Gay-Lussac’s law, the increasing temperature of the air results in a proportional rise in pressure within the balloon. This heightened pressure forces the rubber material of the balloon to stretch, causing the balloon to expand. The principle demonstrated here is crucial for understanding how gases respond to temperature changes under constant volume conditions.

### 8. Fire Extinguishers

Inside a fire extinguisher, there is a pressurized gas, often carbon dioxide or nitrogen, along with a fire-supporting agent. When the extinguisher is activated by pulling the pin, the valve gets opened, allowing the pressurized gas to escape. The rapid release of the pressurized gas leads to a decrease in temperature as the gas expands. This cooling effect is beneficial in firefighting, helping to lower the temperature of the surrounding air and suppress the flames. The controlled application of Gay-Lussac’s law ensures the effective functionality of the extinguishers in emergency situations, where understanding the connection between temperature and pressure is crucial for efficient fire suppression.

A basketball is typically filled with air, and the pressure inside the ball is affected by changes in temperature. As per Gay-Lussac’s law, when the temperature of the air inside the basketball increases, the pressure also rises proportionally, assuming constant volume. This is particularly evident during warm weather or when the ball is exposed to direct sunlight. The increase in temperature leads to an expansion of the air molecules within the ball, causing an uptick in pressure. As a result, the basketball becomes firmer and more inflated. Conversely, in colder temperatures, the air molecules contract, resulting in decreased pressure and a softer basketball. This real-world application of Gay-Lussac’s law is essential for athletes and sports enthusiasts who need to consider environmental conditions when inflating and using basketballs for optimal performance.

### 10. Hot Air Balloon

In a hot air balloon, the air inside the balloon is heated using a burner, causing the temperature of the air to rise significantly. As the air inside the balloon becomes warmer, its pressure becomes higher than the surrounding cooler air. This pressure difference leads to the expansion of the balloon, creating lift. The balloon rises because the hot air inside is less dense than the cooler air outside, showcasing the direct relationship between temperature and pressure as described by Gay-Lussac’s law. This principle is fundamental to the mechanics of hot air balloons, making them a compelling example of the scientific laws governing the behaviour of gases.

### 11. Car Engine

Inside an internal combustion engine, fuel is mixed with air and ignited to produce a high-temperature, high-pressure environment. As the fuel-air mixture ignites and burns, the temperature within the engine’s cylinders increases, causing a corresponding rise in gas pressure. This elevated pressure forces the piston down, turning the crankshaft and ultimately propelling the vehicle forward. Gay-Lussac’s law helps explain the relationship between temperature and pressure in the combustion process, highlighting how controlled conditions are essential for the efficient operation of a car engine.

### 12. Weather Balloons

Weather balloons serve as a clear example of Gay-Lussac’s law in atmospheric studies. These balloons are equipped with instruments and sensors and are released into the atmosphere to gather data about temperature, pressure, and humidity at different altitudes. As a weather balloon ascends, it traverses through layers of the Earth’s atmosphere where temperatures change. As the balloon rises to higher altitudes where temperatures typically decrease, the gas inside experiences a reduction in temperature, causing a corresponding drop in pressure. Monitoring these variations allows meteorologists to create profiles of the atmosphere, enhancing our understanding of weather patterns and atmospheric conditions.

### 13. Airplane Cabin Pressure

As an aircraft ascends to higher altitudes, the external atmospheric pressure decreases. To maintain a comfortable and safe environment for passengers and crew, airplanes are pressurized. Inside the cabin, the air pressure is regulated to a level comparable to that experienced at lower altitudes. According to Gay-Lussac’s Law, as the plane climbs to higher altitudes, the temperature outside the cabin decreases. The aircraft’s environmental control system adjusts the cabin temperature and pressure, ensuring that passengers experience a comfortable and safe environment despite the changes in external conditions. This regulation of cabin pressure aligns with the principles of Gay-Lussac’s law.

### 14. Camping Gas Canisters

Camping gas canisters serve as an example of Gay-Lussac’s Law when considering the behaviour of compressed gases within a confined space. These canisters typically contain liquefied petroleum gas (LPG), such as propane or butane. As the camping stove is ignited, the gas is released from the pressurized canister. When the camping stove burns the gas, it undergoes combustion, and the temperature within the canister increases. As a result, the pressure of the gas rises proportionally. This controlled release of pressurized gas allows for a consistent and regulated fuel supply for cooking.

### 15. Scuba Diving

In scuba diving, the pressure increases with depth, causing the air in the scuba tank to compress. As divers descend into the water, they experience increased pressure due to the weight of the water column above them. This compression leads to an increase in the temperature of the compressed air. On the other hand, during ascent, the pressure decreases, and the air in the tank expands, which results in a decrease in temperature. Divers must carefully manage their descent and ascent rates, considering the impact of temperature and pressure changes on the volume of air in their tanks. Gay-Lussac’s Law plays a crucial role in understanding these dynamics and ensuring the safety and effectiveness of scuba diving activities.

### 16. Hot Springs

Hot springs are formed when groundwater is heated by geothermal heat sources beneath the Earth’s surface. As the water percolates through the Earth, it encounters hot rocks and magma, causing it to heat up. As the water temperature increases due to geothermal activity, so does the pressure of the dissolved gases and steam within the Earth’s crust. When the water reaches the surface through a hot spring, the release of pressure leads to the expulsion of hot water and steam. The application of Gay-Lussac’s Law helps us understand the relationship between temperature and pressure in the formation and behaviour of hot springs.

### 17. Air-Conditioning

Within an air conditioner, a refrigerant undergoes a cyclic process of compression, condensation, expansion, and evaporation. As the refrigerant is compressed, its temperature and pressure rise. Subsequently, the compressed gas releases heat outside the building through condensation. Upon expansion, the refrigerant cools down, allowing it to absorb heat from the indoor air during evaporation. This process not only lowers the temperature but also decreases the pressure. By manipulating temperature and pressure in a controlled manner, air conditioners can effectively cool and dehumidify indoor spaces, showcasing the practical application of Gay-Lussac’s law in maintaining thermal comfort.

### 18. Soda Cans

Soda cans are pressurized with carbon dioxide to keep the dissolved gas in the liquid. When a soda can is exposed to higher temperatures, such as being left in the sun or stored in a warm environment, the absolute temperature of the gas inside increases. As a result, the pressure in the can rises proportionally, leading to an increase in internal pressure. This phenomenon can be observed when opening a warm or shaken soda can, resulting in a more forceful release of carbonation. Moreover, soda cans left out in the sun could explode due to the increase in temperature and pressure inside.

### 19. Hiking in the Mountains

As hikers ascend to higher elevations, the atmospheric pressure decreases due to a reduction in the weight of the air column above. In mountainous regions, the decrease in atmospheric pressure is associated with a decrease in temperature. As hikers climb, they may notice a drop in temperature, and this cooling effect is a consequence of the decrease in air pressure. Some of them might experience difficulty in breathing and nose bleeding. It all happens due to the pressure difference as explained by Gay-Lusac’s law.