Wearing 3D Glasses for Class, with More Than 100 Props, This Course at Zhejiang University is Super Cool!

Recently, in a class at Zhejiang University, nearly 200 students received a special greeting gift—each person got a pair of 3D glasses. Some students put on the glasses in surprise immediately, while others took photos and posted them on WeChat Moments to "show off how cool they are".

In fact, these 3D glasses are just one of more than 100 sets of teaching props for this course. There are also cat's eye stone rings, telescopes, multiple prisms, 3D cameras, high-speed cameras and so on. This made many students who did not get the course become "green with envy" and expressed that they are jealous.

This course is called The Mystery and Application of Vision. It was first offered in 2013, and over the 6 years since then, its popularity at Zhejiang University has been increasing continuously. The number of students each semester has grown from just over 100 at the beginning to nearly 200 now.

These "weird" little questions can you answer them?

The Mystery and Application of Vision is a general education course offered by the College of Optical Science and Engineering of Zhejiang University. The instructor Zhang Haijun is a professor at the College of Optical Science and Engineering of Zhejiang University.

This course was originally the professional course Physiological Optics of the College of Optical Science and Engineering. Later, Zhang Haijun developed it into one of the earliest general education courses on vision offered by Chinese universities.

"The human eye is the most important part of the information perception system, because more than 80% of human information comes from vision," Zhang Haijun said, "Visual knowledge is also closely connected to the rapidly developing information technology today. It is a pity to only offer this course at the College of Optical Science and Engineering. I hope to share this knowledge, as well as the scientific research experience and research results I have summarized and achieved over the years, with students through the form of a general education course."

In class, Zhang Haijun threw one "simple" "difficult question" after another to students, leading them into thinking in class.

How can carp survive for a long time after leaving water? When a nearsighted person dives into a transparent pool, does their myopia get deeper or shallower? Can nearsightedness and presbyopia cancel each other out? Is there a fish with four eyes? What shape is a cat's pupil? Which insect has the most eyes? Why does a picture look like Marilyn Monroe when it is shrunk, but unexpectedly looks like Albert Einstein when it is enlarged?

When the teacher asked the question "Why do tarsiers always turn their heads when looking at things", the students looked at each other in blank dismay and discussed in low voices. Some students guessed that it might be because tarsiers are overly agile.

Instead of responding to students with the common knowledge-indoctrination answer, Zhang Haijun smiled and opened a carefully prepared short video. In the video, the tarsier opened its big eyes, and its pupils never moved at all. When there was any sign of movement around, it "whooshed" its head around to look. After watching the video, everyone suddenly realized that it turned out that a tarsier's eyes can only look straight and cannot rotate, which makes it always turn its head nimbly to see the surrounding environment clearly.

Various props & novel assignments & teaching through lively activities

What is the 3D glasses given to everyone used for? Students can use it to watch the 3D stereoscopic images they made by themselves, and they can also use it to watch 3D movies in daily life.

Zhang Haijun assigned students the assignment of making 3D stereoscopic images. Students need to take two photos that imitate the binocular parallax of human eyes, and then use the self-compiled software provided by the teacher to quickly synthesize a 3D stereoscopic image, and observe the 3D effect with the 3D glasses gifted by the teacher in class.

For this purpose, Zhang Haijun spent a large sum of money to purchase a batch of expensive 3D cameras. Students borrow 3D cameras in groups of three to shoot their final course assignments. When students got the 3D cameras, they were excited and curious. Some couldn't wait to have a try, while some held them and looked at them carefully from all sides, and their joy was obvious to all.

In this course, students also have the opportunity to use high-speed cameras that are almost impossible to access in daily life, and use it to observe the world that cannot be seen by the naked eye.

When a water-filled balloon explodes, will the water maintain the original shape of the balloon first? Which part of a blown soap bubble will start to disappear first? In which direction will the ink diffuse when it drops into water? The videos shot by high-speed cameras and slowed down dozens or hundreds of times make up for the wonderful world that cannot be observed by human eyes.

Jin Shuyin, a sophomore majoring in Teaching Chinese to Speakers of Other Languages, said she is very interested in the assignment of making "optical illusion animation". Optical illusion animation is a small animation assignment that combines the principle of visual persistence.

It takes a short period of time for a light signal to be transmitted to the brain nerves. After the effect of light ends, the visual image does not disappear immediately. This phenomenon of vision is called "visual persistence".

"I made a stop-motion animation of a villain whose skirt was blown up (stop-motion animation is a type of optical illusion animation, which uses the principle of visual persistence to connect still photos to produce an animation effect). This assignment made me realize that those things that seem far away from us, like animation production, actually trace their roots back to these simple scientific principles mentioned in class."