Although many people believe each side has a different role in retaining or reflecting heat, there is a scientific explanation and an answer from manufacturers that make clear which side to use and why the difference in appearance exists.

The real reason aluminum foil has a shiny side and a dull side

The difference between the two surfaces of aluminum foil comes from the industrial manufacturing process. In the final stages of production, the material passes through rollers that reduce its thickness until it becomes a very thin sheet.

To keep it from tearing during this process, manufacturers place two layers of aluminum together and run them through the rollers at the same time. As a result, the surfaces that come into contact with the polished metal of the machinery get a shiny finish, while the surfaces facing each other have a dull appearance.

This explanation is documented by Reynolds, a manufacturer of household aluminum foil, and by research on industrial aluminum rolling published in scientific journals, such as the study “Experimental investigation of surface roughening of the matte side in pack rolling” published in the Journal of Materials Processing Technology.

Is there a correct side of aluminum foil for cooking?

With standard aluminum foil, it does not matter whether the shiny or dull side touches the food. Both surfaces can be used interchangeably to wrap food, cover containers, cook in the oven, or store prepared dishes.

Reynolds explains in its official usage guide that the difference in appearance is a result of the manufacturing process and does not affect the product’s performance. So placing the shiny side in or out does not noticeably change the cooking result.

The belief that the shiny side retains more heat or cooks food faster has no practical basis for standard aluminum foil.

What does science say about the difference between the two sides?

A scientific study published in 2020 in the journal Biotechnology Reports, titled “Reflectivity measurements of the matte and shiny sides of household aluminum foil: application to the design of a light concentrator for photobioreactors”, analyzed the reflective properties of the two surfaces of household aluminum foil.

The researchers measured the reflectivity of both sides and found differences in the way they reflect light: the shiny surface has greater specular reflection, while the dull side has greater diffuse reflection.

However, the study also found that both surfaces have virtually the same total reflectivity: about 86% in the visible spectrum and 97% in the near-infrared.

These results help explain why the two sides look different but have similar overall reflective properties. The study did not directly evaluate food cooking times.

Is there any exception where the side does matter?

There is a type of aluminum foil that comes with a nonstick coating, which has a special finish designed to keep food from sticking to the surface.

On these products, the manufacturer indicates which side should touch the food. In the case of Reynolds nonstick foil, the dull surface has a special treatment and should face the food.

So before using it, it is a good idea to check the package and the product instructions.

Its effectiveness is explained by the presence of acetic acid, a compound with antifungal properties that can inhibit the growth of certain microorganisms.

How does white vinegar work against mold in the home?

White vinegar contains acetic acid, a compound with antifungal and antibacterial properties that can help eliminate certain types of mold found in the home. Its action comes from its acidic nature, which makes it harder for certain fungi and microorganisms to grow.

Household white vinegar usually contains between 5% and 8% acetic acid, a moderately strong compound with a pH of around 2.5 that can disrupt the growth of many fungi and microorganisms, including Penicillium chrysogenum.

To use it, it is recommended to pour undiluted white vinegar into a spray bottle and apply it directly to the affected surface. Let it sit for at least an hour, then scrub gently with a brush.

What precautions should be taken when using white vinegar to clean moldy surfaces?

Although it is a household product, using it requires some precautions to avoid damaging materials and reduce exposure to mold spores.

Before starting, it is a good idea to ventilate the area and wear gloves, eye protection, and a mask. One of the most important warnings is that vinegar should never be mixed with bleach, as it can release toxic gases.

On the other hand, the U.S. Environmental Protection Agency (EPA) recommends repairing leaks, drying materials completely, and preventing moisture from building up

What surfaces can white vinegar be used on?

White vinegar can be used on different household surfaces, although its effectiveness depends on the material and how deeply the mold has penetrated.

However, it should not be used on the following surfaces:

• Marble and natural stone: their acidity can damage the finish and leave marks on materials such as marble and limestone.
• Wood floors: they can damage the protective coating and affect the finish.
• Electronic screens: they can damage anti-glare treatments and some touch coatings.
• Metals: they can promote corrosion in materials such as aluminum and copper.
• Porous materials: it is usually not effective at removing mold that has penetrated deeply, as can happen in carpets and ceiling tiles.

What other ingredients can help fight mold?

In addition to white vinegar, there are other household products that can help control certain types of fungi. Among the alternatives are:

• Baking soda: it has antimicrobial properties and can help control the growth of some fungi. You can make a paste by mixing it with water, apply it to the affected area, let it sit for at least 10 minutes, and then scrub to remove the residue.
• Hydrogen peroxide: A 3% hydrogen peroxide solution can be used on hard surfaces. It is recommended to let it sit for at least 10 minutes before scrubbing and cleaning.
• Tea tree oil: it contains terpinen-4-ol, a compound with antimicrobial properties. Healthline cites a 2015 study that found it was more effective at inhibiting mold growth than vinegar and some commercial cleaners. A solution can be made with one teaspoon of oil per cup of water.

The structure is in Kasukabe, in Saitama prefecture, and is part of a system designed to control excess water from the region’s rivers.

Its infrastructure can collect large volumes of water during heavy rainfall and divert them to another channel to reduce the risk of overflow in urban areas.

What the giant underground structure Japan built to protect cities near Tokyo looks like

The project is known as the Metropolitan Area Underground Discharge Channel and is located in Kasukabe, in Saitama prefecture. It is a flood-control system that mainly protects the Nakagawa and Ayase river basins and communities in that metro area. It has a tunnel 6 kilometers long, built about 50 meters underground, connecting different water intake points to the Edogawa River.

One of the most striking sections is the pressure-regulating tank, a huge underground chamber 177 meters long, 78 meters wide and 18 meters high. Inside, it is supported by 59 concrete columns, each weighing 500 tons, creating a scene reminiscent of a temple.

How the system works to divert water and prevent flooding

The system is designed to kick in when heavy rains raise river levels in the region. Instead of allowing excess water to spread through urban areas, the system collects it through five massive vertical shafts connected to the underground tunnel. From there, the flow moves to the pressure-regulating tank, which reduces the force of the water and allows it to be directed in a controlled way to the Edogawa River.

The final stretch has four high-capacity pumps that push the water into that river. According to official information from Japan’s Ministry of Land, Infrastructure, Transport and Tourism, the system can handle a maximum discharge capacity of 200 cubic meters per second. To put that figure in perspective, the agency says it can move a volume equivalent to an Olympic-size 50-meter pool in about one second.

Why the underground tank has 59 columns weighing 500 tons each

The huge concrete columns were not placed only to support the structure’s roof; they also serve a structural safety function. The tank was built in an area with a high groundwater level, and there is a risk that the pressure of the surrounding water could push the structure upward. The weight of the columns helps counteract that force and keeps the tank from rising or losing stability.

The tank also serves a hydraulic function because it slows the water coming in from the tunnels and allows the pumps to operate steadily. It also helps regulate pressure changes before the flow is discharged into the river.

According to the manufacturer in its official manuals, this option begins working after at least six hours from activation and has a specific indicator on the control panel.

The process is simple, though it is not available on all refrigerators. That is why it is important to know what this function does, how to activate it, and what to do to turn it off when it is no longer needed.

What happens when you hold the Quick Freeze button on the refrigerator for 3 seconds

The Quick Freeze button has two different functions on certain Beko refrigerators. A normal press activates quick freezing, which lowers the temperature in the freezer compartment to freeze food in less time.

However, when it is held down for three seconds, Eco Extra is activated, a second function that is not meant to freeze food faster, but to change how the appliance works so it uses a more economical power mode.

The manual identifies this option as “Eco-Extra (Special Economic Usage)” and says it is activated by a long press of the Quick Freeze/Eco Extra button.

What is Eco Extra mode for and how does it help save energy

Eco Extra mode is designed to reduce the refrigerator’s energy use by operating more efficiently. According to Beko, once the function is activated, the appliance begins operating in that mode after at least six hours.

The manufacturer also explains that when Eco Extra is active, the economy-use indicator lights up on the control panel. This signal shows that the setting is working.

It is worth noting that this function is different from quick freezing because, while Quick Freeze intensely cools the freezer to preserve large amounts of food recently added, Eco Extra changes how the appliance operates with the goal of saving energy.

How to turn off Eco Extra mode on the refrigerator

To turn off economy mode, the process involves pressing and holding the Quick Freeze button again for three seconds to deactivate Eco Extra, according to the Beko manual.

The economy-use indicator on the panel shows whether the function is still active. The manufacturer recommends checking the instructions for each refrigerator model, since functions and controls may vary by unit.

This product contains acetic acid, a compound with cleaning properties that can act on certain residue buildup on metal surfaces.

To understand why this ingredient is used and what happens when it comes into contact with a rusted surface, it is necessary to know the chemical reaction it produces and the precautions to keep in mind before applying it.

What Spraying Vinegar on House Keys Is For

House keys are exposed to constant contact with hands, moisture and different surfaces, so they can accumulate dirt, stains and signs of wear over time. In some cases, they may also show traces of rust or lose the original shine of their surface.

That is why, to treat certain stains, one of the household products used is white vinegar.

Spraying vinegar on house keys: What problem does it help solve?

According to New Mexico State University, vinegar contains acetic acid, a compound that works as a mild acidic cleaner. Using it can help remove rust stains, mineral deposits and the darkening that appears on metals such as brass and copper.

For that reason, it can be useful for cleaning certain metal keys that have surface stains.

How to Apply Vinegar to House Keys Step by Step

The process consists of simple steps:

• Put white vinegar in a spray bottle and spray the keys until the metal surface and grooves are covered.
• Let it sit for a few minutes to help loosen built-up dirt and stains.
• Gently scrub with a soft-bristle brush, paying attention to the small ridges.
• Rinse with a little water to remove any vinegar residue.
• Dry completely with a clean cloth or paper towel to prevent moisture from remaining.

To make sure it is working properly, the agency advises using a refrigerator thermometer, since the appliance controls do not always show the actual temperature.

What it’s for and why the FDA recommends keeping the refrigerator at 40 F or lower

Cold temperatures help keep dangerous microorganisms from multiplying quickly in perishable foods. That is why keeping the temperature at 40°F or lower is essential for storing meat, poultry, fish, eggs, dairy products, and leftovers.

The FDA warns that bacteria that cause foodborne illness can multiply rapidly when foods are left at room temperature. “The amount of bacteria that cause these illnesses can double every 20 minutes,” the agency says.

The recommendation also includes keeping the freezer at 0 F (-18 C) or lower.

What happens if the refrigerator goes above 40°F?

When the refrigerator stays above 40 F (4.4 C), conditions can encourage the growth of bacteria that pose a health risk. Microorganisms linked to foodborne illness include Salmonella, E. coli and Listeria.

The FDA also warns that leaving perishable foods out of the refrigerator for two hours or more allows bacteria to multiply quickly. If the room temperature is above 90 F (32 C), that limit drops to one hour.

How to check whether the refrigerator is at the right temperature

The FDA recommends using an appliance thermometer, a low-cost tool that lets you know the refrigerator’s actual temperature. The process is:

1. Place a dedicated thermometer inside the refrigerator.
2. Check the reading regularly to make sure it does not exceed 40°F (4.4 C).
3. Adjust the temperature control if the appliance is warmer than recommended.
4. Check the reading again to confirm the refrigerator has reached the proper level.

Baking soda, on the other hand, works through a chemical reaction that neutralizes some of the acids in tomato, thanks to its composition and alkaline nature.

What is the purpose of adding baking soda to tomato sauce?

Adding baking soda to tomato sauce helps reduce its acidity and create a smoother, more balanced flavor. This ingredient acts on the tomato’s natural acids, mainly citric and malic acid, which are responsible for its characteristic tart taste.

Unlike sugar, which can mask the perception of acidity by adding sweetness, baking soda acts directly in a chemical reaction that neutralizes some of those acids.

How does baking soda remove the acidity from tomato sauce?

Baking soda is an alkaline substance that, when it comes into contact with the tomato’s natural acids, produces an acid-base neutralization reaction.

During this process, the baking soda reacts with the acids and forms a salt, water and carbon dioxide. The latter is released as small bubbles, so you may notice the sauce start bubbling after the ingredient is added.

The reaction reduces the acidity of the dish because it turns some of the acids into less acidic substances.

How much baking soda should you use to remove the acidity from tomato sauce?

The recommended amount is about 1/4 teaspoon of baking soda for every 500 milliliters of tomato sauce. It is important not to overdo it, since too much can change the flavor of the dish.

To add it properly, it is recommended to stir in the baking soda when the sauce is almost ready, stir it in and let it simmer for a few minutes. It is normal for bubbles to appear because of the chemical reaction.

After that, it is a good idea to taste the sauce and see whether it needs any adjustment. If it still tastes too acidic, you can add a very small additional amount, always in moderation.

What spraying vinegar on windows is for

Vinegar helps clean glass and leave it streak-free and film-free. It works on grease, smoke, stuck-on dust and water stains or mineral buildup that collect on windows, both inside and out. The result is clearer, shinier glass, without that cloudy layer that often remains when you clean with water alone.

Vinegar contains acetic acid, a mild acid that dissolves grease, the oily film left by pollution and mineral deposits (the limescale or white marks left by hard water). Those residues are precisely what water alone can’t remove and what cause glass to look cloudy or streaked.

It also evaporates quickly and leaves no residue. Many streaks on glass don’t come from dirt, but from the film left behind by some cleaners as they dry. Because it evaporates cleanly, vinegar doesn’t leave that layer, which is why the glass stays clear.

How to apply it correctly

The process is simple, but doing it right makes all the difference:

• Make the mix: the usual method is to dilute white vinegar with water in equal parts, half and half, in a spray bottle.
• Spray it on the glass and, if there is stuck-on dirt, let it sit for a few seconds.
• Wipe with a microfiber cloth, a squeegee or crumpled newspaper, which doesn’t leave lint and helps keep streaks away.
• Dry thoroughly, going over the edges, where moisture usually collects.

For this reason, specialists recommend caution when washing shirts, pants, and other technical garments with fabric softener, since using it could affect some of the features that make it comfortable to train in.

Why don’t experts recommend using fabric softener on athletic wear?

Athletic wear is designed to help wick away sweat and keep the body dry during physical activity. Many garments made with technical polyester use fabric structures that move moisture from the surface of the skin to the outside, where it can evaporate.

This mechanism is known as wicking or capillary moisture transport. However, fabric softeners contain conditioning agents that deposit on the fibers and can change how the fabric behaves.

What effect does fabric softener have on athletic fabrics?

A study published in 2019 in the International Journal of Clothing Science and Technology, titled “Influence of repeated treatment with household fabric softener on the comfort characteristics of cotton and polyester fabrics,” analyzed how the behavior of fabrics changes after repeated application of fabric softeners commercially.

Researcher R. Rathinamoorthy studied cotton and polyester fabrics subjected to five, 10 and 15 treatment cycles. During the experiment, he evaluated different characteristics:

• Water absorption: the fabric’s ability to take in moisture
• Air permeability: how easily air passes through the fabric
• Moisture transport: the ability to move liquid through the fibers.
• Thermal conductivity: a property related to heat transfer.

The results showed that repeated application of fabric softeners could significantly alter some of these properties, which are essential for garment comfort.

How does this affect people who exercise?

When a garment loses some of its ability to move moisture, it can hold more sweat close to the skin and create a feeling of discomfort during workouts.

Among the possible effects are:

• More moisture buildup in certain areas
• A wet or sticky feeling
• Changes in drying speed
• Changes in the fabric’s ventilation.

How should athletic wear be washed to preserve its properties?

To avoid altering the characteristics of technical garments, the sportswear brand RevolutionRace recommends following each manufacturer’s washing instructions and skipping fabric softener when it comes to athletic wear designed to wick away perspiration.

It is also advisable to:

• Use detergent according to the label directions
• Avoid washing temperatures higher than recommended
• Follow drying instructions to preserve the fibers.

That way, shirts, pants, leggings, and other training clothes can be cared for without unnecessarily compromising their textile properties.

This home remedy consists of applying the product directly to the affected areas, letting it sit for a few minutes, and then finishing the cleaning with a brush.

How does hydrogen peroxide work to remove toilet stains?

Hydrogen peroxide can help remove some surface stains from the toilet thanks to its oxidizing action.

When it comes into contact with organic residue, it helps break down the compounds that create certain marks and odors. It also has disinfecting properties that can reduce the presence of some microorganisms.

How do you prepare and use this cleaning trick?

To try this method, you can use 3% household hydrogen peroxide, or 10-volume hydrogen peroxide. The process is simple:

• 1. Pour the hydrogen peroxide into a clean spray bottle.
• 2. Spray the areas of the toilet with stains, especially under the rim and on the inside surfaces.
• 3. Let it sit for about 10 to 15 minutes.
• 4. Scrub with a toilet brush and flush to remove the residue.

It is recommended to wear gloves and avoid mixing hydrogen peroxide with other products such as bleach, vinegar or ammonia.

How often can you use the trick of spraying hydrogen peroxide in the toilet?

There is no set universal frequency for using hydrogen peroxide in the toilet. It can be used occasionally when surface stains appear, without having to make it part of every cleaning.

For routine maintenance, the recommendation is to clean the toilet regularly with a product designed for bathrooms and a brush. If stains persist, they may be caused by mineral deposits or limescale, and that requires a different type of treatment.

The advice is to leave it on one of the shelves so it can absorb some of the moisture buildup inside.

What Is Putting a Roll of Toilet Paper in the Fridge Good For?

The goal of this trick is to take advantage of the paper’s absorbency to hold some of the moisture that builds up inside the fridge. That can help reduce condensation and keep the appliance from getting too humid.

It is also said to absorb some of the odors given off by foods like fish, cheese, and onions. To try it, place a new, dry roll on one of the shelves without letting it come into contact with food.

How Often Should You Replace the Toilet Paper Roll in the Fridge?

The roll should be replaced every three or four weeks. You can also change it sooner if you notice it has absorbed too much moisture, lost its firmness, or is damp.

For the trick to have any effect, it is important to use dry paper and keep the roll away from liquids or food, since if it gets damp, it is not a good idea to leave it in the fridge.

What Are the Benefits of Putting a Roll of Toilet Paper in the Fridge?

Among the benefits attributed to this homemade method are:

• Absorbing some of the moisture: the paper can hold a certain amount of water in the air inside the fridge.
• Reducing bad odors: it can absorb some of the moisture associated with odors from certain foods, although it does not replace proper cleaning.
• Reducing condensation: by holding some of the moisture, it could help reduce small pools of water.

The recommendation is backed by Iowa State University, which shares a series of tips for cleaning a vehicle and, among them, recommends this combination not only for cleaning different surfaces but also for removing bad odors.

In the car, windows, mirrors, screens, and light covers can be cleaned using a vinegar mixture

The university recommends vinegar for making a homemade car cleaner, since its acetic acid content helps dissolve residue and neutralize the compounds behind bad odors.

The guidance is to use it diluted in water, making a 50/50 mixture. This blend can be used to polish windows, mirrors, screens, and light covers with a lint-free cloth.

The mixture also works to remove any unwanted smell: “There will be no lingering vinegar smell once it dries. Water and vinegar are quite effective even against cigarette smoke,” it says.

Other university recommendations for cleaning the car

For hard-to-reach spots like the inside of the doors or seat belts, the recommendation is to clean them with a damp cloth.

Car mats, meanwhile, can be cleaned with warm water and a few drops of dish soap. The university’s advice is to lay them on a flat surface, apply the mixture, and then scrub with a soft brush.

The day chosen for cleaning can also make a difference. The advice is to pick a sunny one and take the opportunity to do a thorough cleaning that includes floor mats, child seats, and covers as well.