Section outline

  • Sign promoting sun safety, illustrating the Slip! Slop! Slap! slogan for UV protection.

    Slip! Slop! Slap! Did you ever hear this slogan? It stands for slip on a shirt, slop on some sunscreen, and slap on a hat. The slogan originated in Australia in the 1980s, but it has since been adopted in many other places around the globe. It sums up simple steps you can take to protect your skin from sunlight. Sunlight consists of a wide range of , some of which are harmful.
    ::滑坡! 滑坡! 滑坡! 你听说过这个口号吗? 它代表着滑倒在衬衫上, 滑倒在一些防晒霜上, 扇打在帽子上。 口号起源于1980年代澳大利亚, 但后来被全球其他许多地方采纳了。 它总结了保护皮肤免受阳光照射的简单步骤。 太阳光包括一系列的, 其中一些是有害的。

    The Waves in Sunlight
    ::阳光的波浪

    Electromagnetic waves are waves that carry through matter or space as vibrating electric and magnetic fields. Electromagnetic waves have a wide range of and frequencies. Sunlight contains the complete range of wavelengths of electromagnetic waves, which is called the . The Figure shows all the waves in the spectrum.
    ::电磁波是指作为振动电磁场在物质或空间中的波浪。电磁波具有广泛的频率和频率。太阳光包含电磁波的全波长,称为 。图显示了频谱中的所有波。

    The electromagnetic spectrum showing various wavelengths and their corresponding frequencies.

    Let There Be Light
    ::让光明照耀

    Light includes infrared light , visible light , and ultraviolet light . As you can see from the Figure , light falls roughly in the middle of the electromagnetic spectrum. It has shorter wavelengths and higher frequencies than , but not as short and high as X rays.
    ::光包括红外线光、可见光和紫外线光。 从图中可以看到,光大约落在电磁频谱的中间。光的波长和频率都比X光短,但没有X光那么短和高。

    Q: Which type of light do you think is harmful to the skin?
    ::问题:你认为哪种光对皮肤有害?

    A: Waves of light with the highest frequencies have the most energy and are harmful to the skin. Use the electromagnetic spectrum in the Figure to find out which of the three types of light have the highest frequencies.
    ::A: 频率最高的光波的能量最大,对皮肤有害。使用图中的电磁频谱来找出三种光的哪一种频率最高。

    Infrared Light
    ::红外光

    Light with the longest wavelengths is called infrared light . The term infrared means “below red.” Infrared light is the range of light waves that have longer wavelengths and lower frequencies than red light in the visible range of light waves. The sun gives off infrared light as do flames and living things. You can’t see infrared light waves, but you can feel them as . But infrared cameras and night vision goggles can detect infrared light waves and convert them to visible images. 
    ::有最长波长的光被称作红外线光。红外线一词的意思是“红下 ” 。 在可见的光波中,红外线光是光波的范围,其波长和频率比亮光波中的红光光低。太阳像火焰和活物一样释放红外光光。你看不到红外光波,但你能感觉到它们像红外光波。但红外摄影机和夜视镜可以探测红外光波并将其转换为可见图像。

    Visible Light
    ::可见光灯

    The only light that people can see is called visible light . This light consists of a very narrow range of wavelengths that falls between infrared light and ultraviolet light. Within the visible range, we see light of different wavelengths as different colors of light, from red light, which has the longest wavelength, to violet light, which has the shortest wavelength (see Figure ). When all of the wavelengths of visible light are combined, as they are in sunlight, visible light appears white. 
    ::人们唯一能看到的光线被称为可见光。 这个光线由红外光和紫外线光之间的非常狭窄的波长波长组成。 在可见范围内,我们看到不同波长的光是不同颜色的光,从红光(波长最长)到紫外光(波长最短的紫外光)(见图 ) 。当可见光的所有波长(如在阳光下)合在一起时,可见光看起来是白色的。

    Spectrum of visible light displaying a range of colors from red to violet.

    Visible light spectrum.
    ::可见光谱

    Launch the PLIX Interactive below to further explore the visible spectrum of light:
    ::启动下面的PLIX互动, 以进一步探索可见光谱 :

    Ultraviolet Light
    ::紫外光

    Light with wavelengths shorter than visible light is called ultraviolet light . The term ultraviolet means “above violet.” Ultraviolet light is the range of light waves that have shorter wavelengths and higher frequencies than violet light in the visible range of light. With higher frequencies than visible light, ultraviolet light has more energy. It can be used to kill bacteria in food and to sterilize surgical instruments. The human skin also makes vitamin D when it is exposed to ultraviolet light. Vitamin D, in turn, is needed for strong bones and teeth. 
    ::紫外线是指“紫外线 ” 。紫外线指光的光波范围,其波长短,频率高于可见光的紫外光。紫外光的频率高于可见光,紫外光的频率高于可见光,紫外光的光能也更大。紫外光可用于在食物中杀死细菌和消毒外科器械。人类皮肤在暴露于紫外光时还产生维生素D。而强骨和牙齿则需要维生素D。

    Too much exposure to ultraviolet light can cause sunburn and skin cancer. As the “slip, slop, slap” slogan suggests, you can protect your skin from ultraviolet light by wearing clothing that covers your skin, applying sunscreen to any exposed areas, and wearing a hat to protect your head from exposure. The SPF, or sun-protection factor, of sunscreen gives a rough idea of how long it protects the skin from sunburn (see Figure ). A sunscreen with a higher SPF value protects the skin longer. Sunscreen must be applied liberally and often to be effective, and no sunscreen is completely waterproof. 
    ::太多的紫外线光照射会导致太阳晒伤和皮肤癌。 正如“滑坡、斜坡、耳光”口号所暗示的那样,你可以通过穿戴覆盖皮肤的外衣、在任何暴露地区使用防晒霜以及戴帽子保护头部免受照射来保护皮肤免受紫外线照射,从而保护皮肤免受紫外线照射。 防晒霜的SPF或保护太阳因素粗略地说明了它保护皮肤免受太阳灼伤的时间(见图 ) 。 具有更高SPF值的防晒霜可以更长时间保护皮肤。 日光屏必须开阔地应用,而且经常有效,没有任何防晒霜是完全防水的。

    Sunscreen bottle with SPF 30 label, indicating sun protection factor.

    Q: You should apply sunscreen even on cloudy days. Can you explain why?
    ::问题:即使在多云的日子,你也应该涂防晒霜。你能解释为什么吗?

    A: Ultraviolet light can travel through clouds, so it can harm unprotected skin even on cloudy days.
    ::A:紫外线光能穿透云层,

    Summary
    ::摘要

    • Sunlight contains the complete range of wavelengths of electromagnetic waves. The entire range is called the electromagnetic spectrum.
      ::太阳光包含电磁波波波长的全部波长范围。整个波程被称为电磁波谱。
    • Electromagnetic waves that are commonly called light fall roughly in the middle of the electromagnetic spectrum. Light includes infrared light, visible light, and ultraviolet light.
      ::通常被称为光的电磁波大约在电磁频谱中间落下,光包括红外光、可见光和紫外线光。
    • Infrared light is light with the longest wavelengths and lowest frequencies. You can’t see infrared light, but you can feel it as heat. Besides the sun, flames and living things give off infrared light.
      ::红外线光是光,波长最长,频率最低。你不能看到红外线光,但能感觉到它热。 除了太阳外,火焰和活物还发出红外光。
    • Visible light consists of a very narrow range of wavelengths that falls between infrared light and ultraviolet light. It is the only light that people can see. Different wavelengths of visible light appear as different colors.
      ::可见光是由红外光和紫外线光之间非常狭窄的波长波长组成的。它是人们唯一能看到的光。 可见光的波长不同,颜色不同。
    • Ultraviolet light has shorter wavelengths and higher frequencies than visible light. Ultraviolet light also has more energy, which makes it useful for killing germs. Too much exposure to ultraviolet light can damage the skin.
      ::紫外线光的波长较短,频率比可见光高,紫外光的能量也更多,因此对杀菌有用,接触紫外光的量太多会损害皮肤。

    Review
    ::回顾

    1. Relate sunlight to the electromagnetic spectrum. Where do the waves that are commonly called light fall on the spectrum?
      ::将阳光与电磁波谱相对应。通常被称为光的波浪在光谱上落到哪里?
    2. Define infrared light. How can infrared light be detected?
      ::如何探测红外线光?
    3. What is visible light? What determines the color of visible light?
      ::什么是可见光? 什么决定可见光的颜色 ?
    4. Describe ultraviolet light. How and why should you protect your skin from ultraviolet light?
      ::描述紫外线光 如何保护皮肤不受紫外线光的影响?