The story of physics genius Albert Einstein proves that even "bad students" can be motivated – when the situation is right. He was bored at elementary school, suffered under his authoritarian teachers and was considered unwilling to learn. After a move to Switzerland he graduated from high school – with average grades but top marks in math and physics.

Wilhelm Conrad Röntgen was kicked out of high school when his teacher suspected Röntgen of drawing a cartoon of him, but Röntgen got into university. He passed the admission test for physics and machine engineering. In 1911, Röntgen received the first Nobel Prize in Physics for the discovery of x-rays. The principles of Röntgen's discovery are still used in medicine and elsewhere today.

In February 1968, students in Münster protested against the conditions at their university. They complained about rotten furniture and bad hygiene. The worst hardships of the post-war years were over and the students thought they were due improvements. The most crowded subjects were medicine and pharmacy. Laboratories and auditoriums were overcrowded. And it was the baby boomer years.

The students also wanted to overthrow a generation of professors, whom they saw as being tainted by the Nazis. It was an era of student rebellion. The university deans decide to introduce the numerus clausus on March 27, 1968. Here, about 2,000 students can be seen holding a "teach-in" in Cologne to discuss what the new rules will mean for studying in the state of North Rhine-Westphalia.

Medicine students in Germany today are likely to sit in lecture halls like this. There's enough space for everyone, and teaching methods are advanced. But only those with the best high school grades are admitted to study medicine and other popular subjects like law, business, math and the natural sciences. You can still apply with low grades, but you'll have to wait, sometimes for years.

Louis Pasteur had to wait. He grew up in a family of tanners – not the most respected beginnings at the time. He was diligent and got a place in higher education in Paris, but quit after becoming homesick. When he realized he would leave high school with bad grades, he decided to repeat a year and do better. Pasteur went on to become an infectious diseases expert and pioneered early vaccines.

Thomas Edison didn't have fun at school. His teacher thought he was an airhead. The truth was Edison was deaf. He spent a few months at school before his mother, a part-time teacher, took on his education. He never studied at university, started his career as a telegrapher and became one of the world's most famous inventors, who developed the phonograph, motion picture camera and much, much more.

Here's Edison (right) and his inventor friend, George Eastman, who founded the Kodak Company. Eastman invented, among other things, photo paper and the film roll. In this photo, he's presenting a movie projector. But the pioneer had quit school just like Edison, and got an early start in business when his father died and he had to earn money to feed the family from the age of 14.

Wilhelm Wien grew up in Ketrzyn in Masuria, Poland. He had to leave the local high school due to his bad grades, but he got private lessons and finished high school in the next big city - Königsberg in Eastern Prussia (now Kaliningrad, Russia). He studied and received a PhD in Berlin and was awarded the Nobel Prize in Physics in 1911 for his analysis of the laws of heat radiation.

Physicist Rudolf Mößbauer got his high school diploma in 1955, long before the introduction of Germany's numerus clausus. He said he'd had problems with his school teachers and called physics "one of the worst subjects to study" – largely due to the bad quality of teaching. But he pursued the subject all the same, researched the laws of atomic nuclei, and received a Nobel Prize in 1961.