Hall 2 THE HISTORY OF LIGHT

Introduction to the Hall

Welcome to the hall of THE HISTORY OF LIGHT. This hall tells the story of how humanity has understood and harnessed light over the past several millennia. Covering 1,035 square meters, the gallery’s main color theme is blue—symbolizing the vast river of history flowing endlessly forward. It also represents the perseverance of generations of optical pioneers, who, like sailors braving stormy seas, stayed firmly on course in their pursuit of truth. Here, let us embark on a journey through time to experience the unyielding spirit of exploration in humankind’s quest to understand light.

The First Encounters with Light

The first exhibit you see is The First Encounters with Light. In ancient times, people lacked a scientific understanding of light, so they expressed awe and reverence through myths and legends. Stories like the celestial hound devouring the moon, Hou Yi shooting down the suns, and other tales of eclipses were all linked to optical phenomena. As observation accumulated, people began to experiment with using light. Some studied by the glow of snow at night—an origin of the Chinese idiom reading by reflected snowlight. Others trapped fireflies in translucent sheep bladders to make lamps, or used the phototactic behavior of plants and animals to catch fish. Though they could not yet explain the nature of light, these early practices marked humanity’s first steps in applying light to daily life. Through information panels and multimedia displays here, you can trace how ancient people moved from revering light, to recognizing it, to making practical use of it.

Stories of Light

Next, we come to the Stories of Light. Over time, people gradually uncovered the laws of light in their daily work and life, leaving behind many stories of wisdom. Ancient Egyptians measured the height of the pyramids by observing the length of shadows. In ancient China, mirrors were aligned to reflect sunlight and create dazzling beams to repel enemy ships. In medieval Europe, scholars began to understand refraction and the path of light by studying atmospheric phenomena. In the 17th century, the Dutch invention of the telescope allowed the human eye to see farther than ever before. Soon after, Newton used a prism to disperse sunlight, proving that white light was composed of many colors and revealing its hidden structure. At this exhibit’s interactive screens, you can browse these fascinating stories across different eras. With a simple touch, you can step into the scientific scenes of the past, experiencing how intuition and observation led humanity to peel back the mysteries of light. These stories not only mark milestones in scientific progress, but also embody humankind’s enduring curiosity and creativity.

Early Optics Abroad

Throughout history, scientists from different cultures and eras contributed breakthroughs that deepened our understanding of light. In the age of geometrical optics, Johannes Kepler formulated his three laws of planetary motion, while Newton used prism experiments to show that white light could be split into rainbow colors. In the era of wave optics, Christiaan Huygens proposed that light behaves as a wave, and Augustin-Jean Fresnel confirmed this through experiments on interference and diffraction. Entering the age of quantum optics, Albert Einstein, building on Planck’s quantum theory, advanced the revolutionary idea that light exhibits wave–particle duality, opening an entirely new frontier for modern optics research. Through interactive touchscreens and illuminated displays, you can explore these landmark discoveries and the lives of the scientists behind them. Step by step, revisit how optics evolved abroad—from geometrical optics, to wave optics, and finally to quantum optics—showing how humanity’s understanding of light has grown ever deeper.

Ibn al-Haytham

This is Ibn al-Haytham, the renowned Arab scholar, scientist, mathematician, and philosopher of the Middle Ages, honored as the Father of Modern Optics. His most groundbreaking discovery was that vision does not come from the eye emitting light, but rather from light reflected by objects entering the eye, forming an image on the retina, and then being transmitted to the brain—allowing us to see. He also noticed that the image formed by the eye’s lens appeared slightly larger than the actual object, leading him to deduce that light undergoes reflection and refraction. These pioneering ideas were compiled into his monumental work, the Book of Optics, which profoundly influenced the development of optics in the West, inspiring later scientists such as Kepler and Newton.

Scroll of Light

Before you is a ten-meter-long interactive digital scroll—The Scroll of Light. This scroll records China’s discoveries and understanding of light across different dynasties, guiding us on a journey through time into the ancient world of Chinese optics. Through the touchscreen, you can explore stories from different eras: the earliest record of pinhole imaging from the Warring States period, the application of concave mirrors for focusing sunlight, and the phenomenon of characters revealed by reflection in bronze mirrors. Though seemingly simple observations, they embody rich optical principles. Even without a modern scientific framework, the ancients—through careful observation and thoughtful reasoning—had already begun to recognize light, harness light, and document their own Chinese chapter in the history of optics.

Classics of Light

Welcome to the Classics of Light exhibit. Books are not only carriers of knowledge but also vital channels for cultural transmission. Here you see precious works left behind by the pioneers of ancient Chinese optics. Shen Kuo’s Dream Pool Essays, an encyclopedic collection of his lifetime observations and insights, has long been regarded as a scientific treasure of ancient China. Zheng Fuguang’s Mirror, Mirror, Enlighten the Foolish analyzes the imaging principles of various mirrors. Other works—such as Ge Shu Bu, Notes on Photographic Instruments, Mirror History, Mo Jing, New Treatise on Celestial Patterns, Brief Records of Physics, Qianfu Lun, Zhou Li, and Kao Gong Ji—all reflect profound thinking and exploration of light and shadow by early scholars. These writings are invaluable legacies for future generations, serving as precious references for the study and advancement of optics. At this exhibit, you can also engage with a quiz board to test your knowledge of optical principles.

Evolution of Lamps

This exhibit is The Evolution of Lamps. Light has always been the source of life and energy, and lamps have been humanity’s primary means of illumination. In ancient times, people used torches; later came candles and oil lamps. Around 1821, British scientists Humphry Davy and Michael Faraday invented the arc lamp, which used carbon rods as filaments. Although it produced light, it was dazzling, consumed a lot of electricity, had a short lifespan, and was inconvenient to use. It was not until 1879, when Thomas Edison developed the practical incandescent lamp, that electric lighting truly entered households, illuminating human nights. In 1893, at the Chicago World’s Fair, Nikola Tesla showcased alternating current (AC) lamps, defeating Edison’s direct current (DC) system and laying the foundation for modern urban lighting.

From fluorescent lamps and energy-saving bulbs, to neon lights and today’s LED smart lighting, the form of lamps has continued to evolve, greatly enriching our daily lives. The exhibit panels detail this evolutionary journey, and the multimedia display also shares the story of Edison’s invention of the electric lamp. Take a moment to explore these milestones in lighting history.

Early Optics in China

China’s early achievements in optics hold an important place in the global history of the field. Many Chinese scholars made remarkable contributions. More than two thousand years ago, Mozi conducted the world’s first documented pinhole imaging experiment, predating similar discoveries in the West by centuries, earning him the title of Pioneer of World Optics. In the late Qing dynasty, Zou Boqi, known as the Father of Chinese Photography, independently developed a domestically made camera and studied imaging principles. Later, Li Renzhong made breakthroughs in microscope manufacturing, laying a foundation for the development of modern optics in China. These early Chinese optical pioneers shone like stars in their respective eras, lighting the path of scientific progress in the nation. Through exhibit panels and interactive multimedia displays, you can learn about their stories and lasting contributions.

Poetry of Light

This exhibit is called Poetry of Light. For ancient scholars, composing poetry was one of life’s greatest joys. Through poetry, they expressed their ambitions, emotions, and reflections. The classical verses inscribed on the glass panels before you not only convey the poets’ lofty sentiments, but also vividly describe optical phenomena. For example, in Li Bai’s Drinking Alone Under the Moon (“I raise my cup to invite the bright moon, with my shadow we become three”), the romantic imagery also reflects the principle of light traveling in straight lines and shadow formation. In Wang Wei’s Deer Enclosure (“The reflected sunlight enters the deep forest, shining again upon the green moss”), the poet beautifully depicts how evening light is refracted into the forest, scattering across the moss. The multimedia display provides detailed explanations of these verses, allowing you to appreciate classical poetry while also discovering the optical principles hidden between the lines.

Wave or Particle?

Here we explore the exhibit Wave or Particle? What is the true nature of light? This question puzzled scientists for centuries. The debate between the wave theory and the particle theory of light runs throughout the entire history of optics, illustrating humanity’s long and difficult journey toward understanding truth. This interactive device will guide you through that exploration.

In the 17th century, two schools of thought emerged. Isaac Newton and his followers proposed the corpuscular (particle) theory, while his contemporary Christiaan Huygens introduced the wave theory of light. Later, Thomas Young and Augustin-Jean Fresnel advanced the wave theory with experiments and theories explaining interference and diffraction. By the mid-19th century, the wave theory had gained dominance. Then, in the early 20th century, Max Planck proposed the quantum hypothesis, and Albert Einstein developed the quantum theory of light, successfully explaining the photoelectric effect. In 1905, Einstein further introduced the concept of wave–particle duality, suggesting that light behaves as both a wave and a particle. Though the essence of light is still being explored, this centuries-long debate has greatly deepened human understanding of nature and contributed profoundly to the progress of science and society.

Achievements of Light — Gnomon

Welcome to the Achievements of Light exhibit. In ancient times, people lived by the rhythm of the sun—working at sunrise and resting at sunset. But without modern clocks, how did they know the time and the seasons? The wisdom of the Chinese people led to the invention of ingenious astronomical instruments that relied on light and shadow: during the day, the gnomon and sundial measured the length of shadows; at night, instruments such as the armillary sphere, simplified armilla, and sighting tube were used to track the stars, often placed atop ancient observatories. Here, you can see restored models of these early instruments and experience how light and time came together in remarkable harmony.

The gnomon is the oldest timekeeping and astronomical instrument in China. The north–south horizontal ruler was called the gui, while the vertical pole at its southern end was the biao. At noon each day, sunlight cast a shadow from the pole onto the ruler, allowing the length of the shadow to be measured. As the seasons changed, the length of the noon shadow followed a yearly cycle. The time span between two consecutive shortest or longest shadows marked a full year. As early as the Western Zhou Dynasty, the statesman Duke of Zhou erected a gnomon in Dengfeng, Henan, to observe celestial movements. Legend has it he humbly welcomed talented individuals, even greeting them while “putting on his shoes in haste.” This image of the Duke of Zhou’s virtue and openness later appeared in Cao Cao’s poem Short Song Style: “When the Duke of Zhou bent low to receive wise men, all under heaven turned their hearts toward him.” The gnomon thus stands as the earliest known timekeeping device in the world.

Achievements of Light — Sundial

The term “sundial” combines ri (sun) and gui (shadow), meaning literally “the sun’s shadow.” It is an ancient Chinese device that uses sunlight and shadow to measure the passage of time. A sundial usually consisted of a bronze pointer and a stone dial plate. When sunlight shone on the sundial, the pointer’s shadow fell across the dial. As the sun moved across the sky, the shadow shifted along the engraved time lines, allowing people to read the local time directly from its position. In ancient China, sundials were often paired with water clocks. During the day, the sundial provided accurate solar calibration, while at night, the water clock continued the measurement—together ensuring round-the-clock timekeeping. This ingenious use of sunlight projection to measure time was one of the great inventions of the Chinese people in astronomical timekeeping, and it remained in use for thousands of years.

Achievements of Light — Armillary Sphere

The armillary sphere is a combination of the armilla and the celestial globe, invented by Zhang Heng, a celebrated scholar of the Eastern Han Dynasty. It was a sophisticated ancient instrument used for observing and demonstrating celestial phenomena. The armilla consisted of several concentric rings forming a spherical framework, representing the positions of celestial bodies on the celestial sphere. By rotating a sighting tube around the central axis, observers could accurately align and measure the positions of stars. The celestial globe was engraved with constellations, the celestial equator, and other markers, while a gear system enabled the sphere to rotate about its axis, simulating Earth’s rotation. In this way, the rising, setting, and paths of the sun, moon, and stars could be visualized directly. The armillary sphere combined mechanical ingenuity with principles of optics, embodying the wisdom and creativity of ancient Chinese astronomers. It remains one of the most iconic instruments in the history of Chinese astronomy.

Achievements of Light — Simplified Armilla

The simplified armilla (jianyi) was an equatorial astronomical instrument invented in ancient China to measure the positions of celestial bodies. It was designed by Guo Shoujing, a renowned astronomer of the Yuan Dynasty, who simplified and improved upon the more complex armillary sphere by separating out the cumbersome four-ring instrument. The result was a far more practical device—predating similar European equatorial mounts by nearly 500 years. The simplified armilla was composed of two perpendicular rings: the equatorial ring, aligned parallel to Earth’s equatorial plane, and the right ascension double ring, mounted vertically at its center and capable of rotation. By adjusting and aiming the sighting tube at a celestial body, observers could directly read its celestial coordinates from the graduated scales on the rings, enabling highly accurate positional measurements.

Achievements of Light — Gnomon Bowl (Yangyi)

The gnomon bowl, also known as the yangfu (“upturned cauldron”), was an astronomical instrument designed by Guo Shoujing during the Yuan Dynasty, specifically for measuring the spherical coordinates of celestial bodies. Its structure resembled a large bowl tilted skyward, hence its name. The principle of the instrument was simple yet ingenious: by observing where the sun’s shadow fell inside the bowl, astronomers could determine the sun’s celestial longitude and latitude. This allowed them to precisely establish the solar terms of the traditional calendar and to keep accurate time. In addition, the gnomon bowl was invaluable in recording solar eclipses. It could measure the orientation of different phases of the eclipse, the exact times of their occurrence, and the extent of the sun’s coverage. With this data, ancient astronomers were able to predict eclipses with remarkable accuracy, making the yangyi an essential tool in both calendrical science and astronomical observation.

Achievements of Light — Ancient Observatory

The ancient observatory served multiple purposes, including shadow measurement, star observation, and timekeeping. Built with bricks and stone, it consisted of a truncated-pyramid platform and a stone gnomon. Between the two small chambers at the top of the platform, a crossbeam created a square opening through which sunlight passed, casting shadows onto the stone gnomon below. By observing the changes in the shadow’s length, direction, and angle, ancient astronomers could calculate calendars and even estimate the distances of celestial bodies. At noon each day, sunlight passing the crossbeam projected a shadow onto the stone gnomon, allowing astronomers to “measure the sun by day and observe the Pole Star by night, thereby regulating morning and evening.” It was with the help of such observations that the Yuan Dynasty produced the Shoushi Calendar, the most advanced calendar in the world at the time—differing from the modern Gregorian calendar by only 26 seconds.

Although the devices appear simple, they embody profound optical principles. They represent the wisdom accumulated by ancient Chinese people through long-term practice, not only guiding agriculture, seasonal rhythms, and daily life, but also advancing the development of astronomy and calendrical science.

Camera Museum

Welcome to the Camera Museum. Before the invention of the camera, only the artist’s brush could capture a fleeting moment. Since the Frenchman Louis Daguerre created the world’s first camera in 1839, humanity’s pursuit of perfect imaging has never ceased. From black-and-white to color, from simple optical structures to integrated opto-mechatronic systems, and from traditional silver-halide film to digital image sensors, camera technology has advanced rapidly over the past two centuries.

The museum displays real cameras from different stages of this evolution. 1839–1924: The birth and early development of cameras. With a growing understanding of optical principles, early wooden cameras and lens-cap exposure cameras without shutters were produced. Several of these precious artifacts are on display. 1924–1960: The period of maturity. Mechanical shutters, optical viewfinders, rangefinders, and automatic shutters became widespread. The introduction of 35mm single-lens reflex (SLR) cameras and other classic brands drove the professionalization of photography. Chinese classics such as Seagull and Pearl River cameras from this era are also exhibited.

1960 onwards: The era of automation and electronics. Film was gradually replaced by digital storage, and the discontinuation of Kodak film in 2009 marked the official end of the film era. The museum also features iconic models from Leica, Compass, Ricoh, and other renowned brands. Here, you can trace the evolution of photography and appreciate its remarkable technological achievements.

Movie Projector Museum

Here we have the Movie Projector Museum. The development of optics gave birth to the movie projector, a device that records and displays moving images, greatly enriching human cultural life. Known as the “seventh art,” cinema ingeniously applies optical principles to open up an entirely new world of light and shadow.

In front of you is a genuine relic—a film projector manufactured in 1981 by the Changchun Film Equipment Factory. You can not only admire this rare artifact up close, but also step into the small theater behind the museum to watch The World of Light and Shadow, a film that takes you through the history of the movie projector and the evolution of cinema itself.

The History of Mirrors

In everyday life, the mirror is the optical tool we use most often, helping us observe and arrange our appearance. The history of mirrors is long and rich. As early as the Qijia Culture (around 2000 BCE) and the Shang and Zhou Dynasties, people were already crafting bronze mirrors. Over time, mirror-making went through many refinements and innovations. Through the bronze mirrors on display here, you can appreciate both the craftsmanship of the reflective surfaces and the decorative motifs on the reverse, revealing the legacy of ancient optical technology and mirror culture.

In another showcase, you will see a particularly special artifact—an openwork “magic mirror” from the Western Han Dynasty. When light shines upon it, the mirror not only reflects light onto the wall but also projects the intricate patterns engraved on its back. This phenomenon is astonishing, because bronze mirrors, being metallic, should be completely opaque.

So how does this magical “light-transmitting” effect occur? The secret lies in the unique casting and polishing process. When molten bronze was poured into the mold, the thicker edges cooled more slowly than the thinner center, causing subtle internal stresses and a barely perceptible bulging at the edges. After painstaking polishing, the mirror’s surface ended up with microscopic convex and concave variations that corresponded exactly to the designs on the reverse side—yet remained smooth to the touch.

When light strikes these microscopic features, the concave areas focus the light into bright spots, while the convex areas scatter the light into darker regions. The reflected image therefore reproduces the patterns from the back of the mirror as a shimmering projection, making it seem as though the mirror itself is “transparent.” This remarkable optical effect showcases the ingenuity and artistry of ancient Chinese craftsmanship.

Telescopes and Eyeglasses

As early as the beginning of the 17th century, the invention of the telescope completely changed the way humans observed the world. In 1608, Dutch spectacle maker Hans Lippershey submitted a patent application for the telescope. Soon after, Galileo Galilei improved the design and used it to observe mountains on the Moon and the satellites of Jupiter, opening a new era in modern astronomy. The arrival of the telescope not only greatly expanded the range of human vision but also enhanced our ability to explore the universe, making it an indispensable optical instrument in scientific research and astronomical observation. With technological progress, telescopes have continued to evolve—from the earliest refracting telescopes, to Newton’s reflecting telescope, and now to today’s high-precision space telescopes. Each innovation reflects humanity’s endless curiosity and wisdom in exploring the vast cosmos.

At the same time, the invention of eyeglasses brought practical benefits to everyday life. Around the 13th century, early spectacles for nearsightedness were produced in Europe. With the advancement of optical theory and improvements in craftsmanship, eyeglasses gradually developed into diverse forms to correct farsightedness, astigmatism, and presbyopia. Beyond being practical tools for vision correction, eyeglasses also reflect the cultural tastes and aesthetics of different eras—their materials, shapes, and decorative styles reveal the lifestyle and artistry of their times.

From telescopes to eyeglasses, these exhibits not only showcase the progress of optical technology but also embody the ways of life and scientific spirit of different periods. Through these precious artifacts, we can better understand the stories behind telescopes and eyeglasses, and appreciate how human ingenuity in optics has continuously pushed the boundaries of vision.

That concludes the Hall. Please proceed to the next hall—OPTICS OF CHINA—to continue exploring the wonders of optics.