have observed that, under the right conditions,

已經觀察到，在適當的條件下，

ordinary clear water droplets on a transparent surface

透明表面上的普通清澈水滴

can produce brilliant colors

可以產生鮮豔的色彩，

without the addition of inks or dyes.

而無需添加油墨或染料。

This iridescent effect is due to what is known

這種虹彩效果是由於我們所知的

as structural color, by which an object

結構顏色造成，意即物體

generates color simply by the way light

僅通過光與其幾何結構相互作用的方式

interacts with its geometric structure.

產生色彩。

In this case, the researchers were able to observe

在本案例中，研究人員能夠觀察

and ultimately model how light travels through droplets

並最終模擬出當光以特定角度進入時

of a particular size when it enters at a particular angle.

它是如何穿過特定大小的液滴。

The model they developed allows them to predict

他們開發的模型讓他們能夠

the color a droplet will produce

在基於特定的光學和結構條件之下。

given those specific optical and structural conditions.

預測出液滴會產生什麼色彩。

The researchers imagined their model

研究人員設想到他們的模型

could be used in the future as a design guide

在未來可以當作一個設計指南

to produce droplet-based litmus tests,

來生產液滴式的石蕊測試，

or color changing powders and inks

或者應用在藝術和化妝品上的

in art and makeup products without the need

變色粉末和油墨，這樣就不需要使用

for potentially unhealthy synthetic dyes.

可能會危害健康的合成染料。

At first, the researchers thought the color they observed

起初，研究人員以為他們觀察到的色彩

might be due to the effect that can cause rainbows,

可能就是造成彩虹的那個效果，

but they soon realized it was in fact

但他們很快意識到他們所觀察到的色彩其實

something quite different.

和彩虹是截然不同的。

They observed that droplets on a flat surface

他們觀察到平坦表面上的液滴

were hemispheres rather than spheres,

是半球體，而不是像雨滴那樣能產生彩虹的

like the raindrops that cause rainbows.

完整球體。

They found that a hemisphere's concave surface

他們發現半球體的凹面處

allows an optical effect called "total internal reflection"

會造成一種稱為「全內反射」的光學效應，

that is mostly not possible in perfect spheres.

這在完美球體中幾乎是不可能會發生的。

The researchers found once light makes its way

研究人員發現，一旦光線成功

into a droplet, it can take different paths,

進入液滴，它會沿著不同的路徑運行，

bouncing two, three, or more times

並在從另一個角度射出去之前

before exiting at another angle.

反射兩次、三次或更多次。

The way light rays add up as they exit

光射線在退出液滴時所累積的路線

determines whether a droplet will produce color or not

會決定液滴是否會產生色彩

and what color is produced.

以及產生什麼色彩。

The color that droplets produce

液滴所產生的色彩

also depends on structural conditions

還取決於結構條件，

such as the size and curvature of the droplets.

像是液滴的大小和曲率。

To test their model, the team produced a layer

為了測試他們的模型，團隊製作了一個

of bi-phase oil droplets of the exact same size

有著兩個大小完全相同，密度卻不同的油液滴膜層，

in a clear Petri dish, which they illuminated

他們把膜層放在透明的培養皿中，

with a single, fixed, white light.

再用一道單一且固定的白光照射這個培養皿。

They then recorded the droplets with a camera

他們接著用環繞在培養皿旁邊的相機

that circled around the dish,

記錄了液滴，

and observed that the droplets exhibited brilliant colors

並觀察到液滴所呈現出的鮮豔色彩

that shifted as the camera circled around.

會隨著相機環行而改變。

This demonstrated how the angle at which light

這說明了所看見的光進入液滴的角度

is seen to enter the droplet affects the droplet's color.

是如何影響著液滴的色彩。

The team also produced droplets of various sizes

該團隊也在單一個薄膜上

on a single film, and observed that

製造了各種大小的液滴，並觀察到

when viewed in a microscope, each droplet

當放在顯微鏡下觀看時，每個液滴

produces a different color depending on its size,

會根據其大小產生不同的色彩，

and the color always emanates

而且色彩總是會

from the contact lines between the various liquids.

從各種液體互相接觸的邊緣處放射出來。

When viewed macroscopically, these droplets together

當以肉眼觀看時，這些液滴群聚一起

just appear a glitter-white color.

所顯現的僅是一團閃閃發光的白色。

The team expects that their model

團隊期待他們的模型

may be used to design droplets, particles, and surfaces

可用於設計液滴、顆粒以及

for an array of color-changing applications

一系列變色應用的表面，

where one could tailor a droplet's size, morphology,

人可以在這個表面上定制液滴的大小、形態

and observation conditions to create a specific color.

以及觀察條件，以創造出特定的色彩。