{"id":50874,"date":"2025-08-16T10:52:44","date_gmt":"2025-08-16T01:52:44","guid":{"rendered":"https:\/\/phys-edu.net\/wp\/?p=50874"},"modified":"2025-08-23T04:57:51","modified_gmt":"2025-08-22T19:57:51","slug":"hidden-trick-discovered-see-infrared-with-your-iphone-take-a-peek-into-the-world-of-infrared","status":"publish","type":"post","link":"https:\/\/phys-edu.net\/wp\/?p=50874&lang=en","title":{"rendered":"Hidden Trick Discovered! See Infrared with Your iPhone (Take a Peek into the World of Infrared!)"},"content":{"rendered":"

This article is also available as a podcast!<\/a><\/p>\n

Peek into the Invisible: Seeing Infrared with Your Smartphone<\/b><\/h3>\n

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This article is also available as a video.<\/a><\/p>\n

In science class, understanding \u201cthings we can\u2019t see\u201d<\/b><\/span> can often be a turning point for students\u2019 comprehension. One of the best examples of this is light<\/b><\/span>. Many students think of light as \u201cwhat we can see,\u201d but in reality, what our eyes perceive is only a small portion of the electromagnetic spectrum, called visible light<\/b><\/span>. So what about the \u201cinvisible\u201d light beyond that? One such type is infrared radiation<\/b><\/span>, which is the focus of this post.<\/p>\n

Infrared is a type of electromagnetic wave<\/b><\/span> with a longer wavelength than visible light. It\u2019s used in a wide range of applications: remote controls, security cameras, temperature sensors, and even space telescopes. Humans, however, cannot see it with the naked eye<\/b><\/span>. But with a clever trick using something everyone has\u2014a smartphone\u2014you can actually make infrared light visible<\/b><\/span>!<\/p>\n

This method allows you to visualize infrared in science experiments, and it might even help you spot security cameras in your home that rely on infrared in the dark.<\/p>\n

What is Infrared?<\/b><\/h3>\n

When we see and recognize objects, our eyes capture waves of light called <\/span>electromagnetic waves<\/b><\/span> emitted from those objects. Among these waves, humans can detect wavelengths from <\/span>380 nm to 750 nm<\/b><\/span>, interpreting different wavelengths as different colors.<\/span><\/p>\n

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Note: \u201cnm\u201d (nanometer) equals 10\u207b\u2079 meters.<\/i><\/i><\/p><\/blockquote>\n

As shown in the diagram, longer wavelengths appear red, and shorter wavelengths appear violet. This sequence is often remembered with the mnemonic: Red, Orange, Yellow, Green, Blue, Indigo, Violet (ROYGBIV)<\/b><\/span>. This range of electromagnetic waves that humans can perceive is called visible light<\/b><\/span>.<\/p>\n

Beyond visible light, there are other types of electromagnetic waves that humans cannot see. For example:<\/p>\n

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  • \n

    Ultraviolet (UV) light:<\/b><\/span> wavelengths shorter than violet<\/p>\n<\/li>\n

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    Infrared (IR) light:<\/b><\/span> wavelengths longer than red<\/p>\n<\/li>\n<\/ul>\n

    While humans cannot detect these directly, some other species can. For instance, cabbage white butterflies are known to see ultraviolet light.<\/p>\n

    Let\u2019s Try Seeing Infrared!<\/b><\/h3>\n

    Infrared light has different types, similar to visible light. There\u2019s <\/span>near-infrared<\/b><\/span>, which behaves much like visible light, and <\/span>mid- and far-infrared<\/b><\/span>, which have longer wavelengths. Here, we\u2019ll focus on near-infrared.<\/span><\/p>\n

    When you press a button on a remote control, it emits infrared waves<\/b><\/span> from the tip. Since infrared is not visible light<\/b><\/span>, you can\u2019t see it with your eyes. This \u201cinvisibility\u201d is actually useful: infrared is used in remotes so that the signal doesn\u2019t bother us in daily life. Technically, visible light could be used for communication, but a blinking visible light on your remote would be distracting.<\/p>\n

    A while back, pointing a remote at a digital camera<\/b><\/span> allowed you to see the infrared signal through the camera screen. This is because the camera\u2019s image sensor can detect wavelengths beyond what human eyes can see, including near-infrared.<\/p>\n

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    However, capturing infrared can alter the colors in photos, since the camera sees light our eyes can\u2019t. Older iPhones could also detect infrared through the camera. But in modern smartphones, infrared is blocked by an IR-cut filter<\/b><\/span> built into the lens. This filter blocks electromagnetic waves longer than 750 nm and lets only visible light reach the sensor, so photos appear more like what our eyes see. Today, almost all digital cameras include IR-cut filters.<\/p>\n

    \"\u30b9\u30af\u30ea\u30fc\u30f3\u30b7\u30e7\u30c3\u30c8<\/p>\n

    When I tried photographing with an iPhone, I couldn\u2019t see the infrared at all!<\/p>\n

    For classroom experiments in the past, we had to bring older digital cameras to see infrared. But recently, I discovered that with one simple trick<\/b><\/span>, you can even see infrared with an iPhone (or other modern smartphones)! You can see it clearly in this video.<\/p>\n