Previous: Who Melted the Earth?
Next: Why Do Bug Bites Itch?



View count:436,858
Last sync:2018-11-09 07:20
Humans have long known that glass bends light. However, it took us awhile to figure out that stacking lenses in a tube would open up a whole new world to science, finally allowing us a peek at the microscopic.

Like SciShow? Want to help support us, and also get things to put on your walls, cover your torso and hold your liquids? Check out our awesome products over at DFTBA Records:

Or help support us by subscribing to our page on Subbable:
Looking for SciShow elsewhere on the internet?

Thanks Tank Tumblr:

It’s the very symbol of scientific endeavor, used by researchers in most every field whether you study elephants or nanobots.  If you do science, you probably need to study the very small before you can get to the big picture.  For more than 400 years we’ve been able to do this thanks to the optical or light microscope, an ingeniously simple device without which we would not have found a cure for polio or been able to make microchips or discovered some of the fundamental properties of light itself.  

And it made it all possible using the same basic technology for hundreds of years.  Of course if you want to start a full-on petri dish throwing, roll up your lab coat sleeves, science fight, all you have to do is raise the question of who really invented the microscope.  Some like to attribute it to the guys who pioneered the telescope, like Galileo and Hans Lippershey, both of whom tinkered with using lenses to get a closer look at things here on Earth.  But many give credit to the Dutch father and son team of Hans and Zacharias Janssen.  

In the late 1500s, they were making their living as eyeglass lens grinders at a time when eyeglasses were like, the Google glass of the day.  It was cutting edge stuff, and everyone wanted it, especially the ones who couldn’t see.  But the Janssens wondered what would happen, if you take a telescope like Galileo’s which had a really big concave lens on one end to gather light and a convex lens on the other to magnify it, and instead used two very small, almost spherical convex lenses.  

They found that their device could magnify things up to nine times and it had a short focal length, meaning it could bring images into focus over a short distance.  This was pretty handy for their extremely nearsighted customers, but their contraptions usefulness for scientific research seemed to have largely escaped them.  

It was 70 years later when the English philosopher, Robert Hooke tricked out the Janssens’ design and used his own version, to study the natural world.  He scrutinized the structure of feathers, they eyes of houseflies and perhaps most famously, thin slices of cork.  The tiny compartments that he saw in the woody tissue reminded him of monk’s chambers and he named this essential unit of life after them: cells.  

But then, scoring another win for team Netherlands, Dutch polymath, Antony Van Leeuwenhoek soon designed his own hand held microscope, with new special lenses that could magnify objects up to 270 times, and suddenly a whole new world was opened up to human eyes for the first time.  Leeuwenhoek discovered organisms that no one had any idea even existed, like bacteria found swimming in rainwater and human saliva, which he called animalcules.  He also observed microscopic nematode worms, tiny water-born rotifers, and was the first to observe human cells, like red blood cells and sperm.  Our understanding of the world around us would never be the same and with each new generation, the microscope took on new modifications to make it sharper, more stable, and more powerful.  

By the late 1800s, we arrived at a version pretty similar to what you know today, with a stage for holding your specimen, a light source, usually underneath, followed by objective lenses that collect and focus the light coming through the specimen, and an ocular lens, or eyepiece that magnifies the image.  This simple setup and the window onto the world that it opened got to be so essential to scientific pursuit that microscopy soon became a kind of science of its own, and any discovery that cracked that window open a little wider got you a Nobel Prize.  

Like in 1926, Austrian chemist Richard Zsigmondy broke the code of how to study particles smaller than the wavelength of visible light by inventing the ultra-microscope, which aimed a high powered light beam at an angle, through a colloid of particles.  Nearly 30 years later, Fritz Zernike won the Nobel Prize in Physics, inventing the phase-contrast microscope, which finally made possible the study of colorless and transparent materials, and we’re not even talking about the whole new wave of technologies that the optical microscope inspired, like the electron microscope, which uses beams of electrons instead of light to magnify images up to ten million times, or the scanning tunneling microscope, which can resolve surfaces down to the atomic level.

Science is amazing. And much of it is made possible by revealing what once had been invisible.  And we’d like to thank Subbable Subscriber Labverse, which aims to let people explore the invisible world via a remote web-based microscope, for choosing this topic.  

If you’d like to choose a topic for a SciShow episode, or sponsor a graphic, or get your own personalized SciShow lab coat, go to to learn more. And if you have any questions, or comments, or ideas, you can find us on Facebook and Twitter, and as always in the comments below.  And don’t forget to go to and subscribe.