Does Aluminum Foil Block Thermal Imaging?

Does Aluminum Foil Block Thermal Imaging?
Does Aluminum Foil Block Thermal Imaging?

Have you ever wondered if aluminum foil will block thermal imaging? You might have heard about thermal imaging or seen it on TV or in the movies, but it’s probably something you’ve never given much thought to. The truth is that thermal imaging is a method of “seeing” objects with infrared waves. In this article, we’ll be answering the questions: What is thermal Imaging? Can any object block thermal imaging? Does aluminum foil block thermal imaging?

As we know aluminum foil is a household item, and it is mostly used to wrap food. It protects your food or meal from contamination or foreign substances. For the same reason, it is also used for a variety of purposes today. It can also be used as an insulator in windows. It also protects any other object from moisture and damage. But you might be surprised to find out that aluminum foil also blocks thermal imaging.

However, some people think it does not? Ok, let us first explore the science behind thermal imaging, and then we will unravel this myth.

What is Thermal Imaging?

Thermal imaging is a technique that uses infrared radiation to produce an image based on temperature differences. Infrared cameras detect infrared energy and produce an image based on this data.

Thermal imaging is also known as infrared thermography. The two terms are used interchangeably. However, there is a slight difference between the two concepts. Infrared refers to the region of the electromagnetic spectrum between microwaves and visible light. However, Thermal imaging is a process of improving the visibility of objects through the detection and analysis of infrared radiations emitted by them.

How does thermal imaging work?

Thermal imagers detect infrared radiation (IR), which is light with a wavelength slightly longer than visible light. While we cannot see IR with our own eyes, we can feel it as heat.

The hotter an object is, the more IR it emits. In fact, all objects emit some amount of IR radiation simply because they are above absolute zero (-273°C). A thermal imager detects this emitted IR energy and creates an image based on it. The colder an object is relative to its surroundings, the brighter it will appear in a thermal image.

Thermal cameras/ Imagers are used by electricians, building inspectors, exterminators, plumbers, and HVAC technicians to detect common issues in households and businesses. Here are the best thermal imaging cameras 2022 come under $500.

A thermal imaging camera employs infrared radiation to produce a more visible image of the object. But then, can any object block thermal imaging?

Can any object block thermal imaging?

When it comes to thermal imaging, several factors determine whether an object can block the camera’s ability to detect heat or not. The material of an object can also affect its ability to block thermal imaging. For instance, glass is transparent to thermal radiation while metal reflects it back. Some other materials absorb the radiation while others reflect it back and forth until they lose their energy.

Thermal Cameras and Objects

The material of an object is one of the biggest factors when determining whether a thermal camera can “see” it or not. For example, we all know that glass is transparent to visible light. However, when we talk about thermal radiation, glass tends to act like a mirror instead of being transparent because it reflects most of the radiation back instead of absorbing it and transmitting it to our eyes. This means that you’ll be able to see thermal imaging through the glass.

Likewise, the material’s molecular structure and thickness decide whether a thermal camera can see through it or not. Thermal cameras cannot see through solid metal objects or walls. The more massive the object is, the less infrared radiation will pass through it. This means that a solid piece of metal will block thermal imaging far more than a piece of wood or plastic. In general, thermal cameras also cannot see through non-metallic objects, like concrete walls, glass, and ceramics because of their thickness and structure.

However, there are other things that a thermal camera can see through, such as smoke, fog, rain, dust, blowing sand, snow, mist, and fog among others. The thickness of the plastic possibly allows thermal cameras to see through it or not.

Does Aluminum Foil Block Thermal Imaging?

The answer is yes; it does block thermal imaging. The aluminum foil blocks thermal images by reducing their overall sensitivity. This means that if you use aluminum foil, you are likely to lower your overall sensitivity and make it harder for the camera to see.

 

Thermal imaging can see through many things. But for this to happen, the thermal imager needs some form of heat energy to reflect from. The thermal camera captures the temperature of objects and displays this data as an image on a screen. The images are called thermograms. These thermograms show various colors that correspond to different temperatures. This way, you can tell which object is hotter or colder than the other by comparing their colors on the thermogram.

 

Now, if you cover any object with aluminum foil, this object will not be visible in thermal imaging because the foil prevents any radiation from passing through it. This is because aluminum foil creates a barrier known as the Faraday cage. A Faraday cage is an enclosure used to block electric fields and electromagnetic radiation by directing these waves into the ground or enclosing them in a metal mesh screen (aluminum).

 

So, aluminum foil blocks thermal imaging by reflecting radiation back to its source. This is because it has low emissivity and high reflectivity properties. Aluminum foil reflects more than 90% of infrared radiation that strikes its surface back to its source. This makes it difficult for thermal imaging sensors to gather data from objects covered with aluminum foil since they receive more reflected radiation than emitted radiation from these objects. This explains why it’s used as a “heat shield” in many applications, including building insulation and space blankets.

 

Interested to know? The aluminum foil can also block the radiation signals from reaching your cell phone. As a result, the phone will be unreachable by other devices. Also, you cannot use that phone to make calls until you remove it from the foil sheet.

 

Final Thought

Thermal imaging is a great tool to see through some objects. But, it is not the only way to see through some objects. For instance, thermal imaging cannot see through some objects, like metals and concrete. On the other hand, thermal imaging can see through other objects, like water, sand, snow, fog, and mist. Also, aluminum foil can block thermal imaging. The aluminum foil blocks thermal imaging by reflecting radiation back to its source. This is because it has low emissivity and high reflectivity properties. That’s why, aluminum foil is used as a “heat shield” in many applications, including building insulation and space blankets. 

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