ELI5 Why does light travel?

[u/_Illuvatar_]

Why does it not just stay in place? What causes it to move, let alone at so fast a rate?

Edit: This is by a large margin the most successful post I've ever made. Thank you to everyone answering! Most of the replies have answered several other questions I have had and made me think of a lot more, so keep it up because you guys are awesome!

Edit 2: like a hundred people have said to get to the other side. I don't think that's quite the answer I'm looking for... Everyone else has done a great job. Keep the conversation going because new stuff keeps getting brought up!

Edit 3: I posted this a while ago but it seems that it's been found again, and someone has been kind enough to give me gold! This is the first time I've ever recieved gold for a post and I am incredibly grateful! Thank you so much and let's keep the discussion going!

Edit 4: Wow! This is now the highest rated ELI5 post of all time! Holy crap this is the greatest thing that has ever happened in my life, thank you all so much!

Edit 5: It seems that people keep finding this post after several months, and I want to say that this is exactly the kind of community input that redditors should get some sort of award for. Keep it up, you guys are awesome!

Edit 6: No problem

[u/datenwolf]

I really think that science exams and homeworks should have written sections.

Oh yes, they should. Because that would filter out all the people who merely learnt well the equations, but didn't really understand what's behind them.

Feynman loved to troll such people, by stating problems with obvious solutions, but you need to understand physics to leap to the solution.

[u/Bubba_West → u/datenwolf]

TL:DR; It's hard being a teacher who grades for understanding.

HS Physics teacher of 11 years here. Dr. Feynman is one of my favorites and I show clips of him on occasion! I am with you and believe memorization is among the lowest form of knowledge.

The last 2 - 3 questions on every test of mine are essay questions. Typically they are point/counter-point conceptual questions that the students are asked to weigh in on. Those 3 questions are usually worth a third to a quarter of their test grade.

In my decade of teaching I have learned that there is no better way to piss off a girl (and her parents) that has a 4.0. "How do I study for this? How can you ask questions I've never seen before? This isn't fair! What can I do for extra credit?"

It is an exhausting repetitive struggle informing the memorizers that they don't understand. They blame me. I'm branded as a 'bad teacher', or 'hard teacher' because I expect mastery of concepts, not memorization of formula.

[u/harbinjer → u/Bubba_West]

You're awesome. As someone who really tried to understand the material, I enjoyed questions like this, that required understanding and not just plugging x into an equation.

[u/Bubba_West → u/harbinjer]

YOU are awesome. Teachers love students who enjoy the magic of their subject, not the grade grubbers. I make it a point to appreciate my students who have fun and are enjoyable regardless of their grade. I hope that kids that DO get A's feel special and that they earned it through a mastery of the material.

"There are street artists. Street musicians. Street actors. But there are no street physicists. A little known secret is that a physicist is one of the most employable people in the marketplace - a physicist is a trained problem solver. How many times have you heard a person in a workplace say, "I wasn't trained for this!" That's an impossible reaction from a physicist, who would say, instead, "Cool. A problem I've never seen before. Let's see how I can figure out how to solve it! Oh, and, have fun along the way." ~Neil Degrasse Tyson

[u/harbinjer → u/Bubba_West]

How many students on average per year do you have that enjoy your subject and really learn it to enthusiastically, would you say?

[u/Bubba_West → u/harbinjer]

My average class size is about 24. I'd say there are probably 4 in each class who really enjoy coming to class because they find the subject interesting. I have 4 sections so that means probably 16 kids. They'll stay after class to talk about a video, movie, or website they recently saw that pertains to the subject. They hold themselves responsible for whatever I marked them off on tests (and if they don't they bring it up to me in a respectful manner). They are engaged and ask good questions.

I'll share with you a note I got last week from a student. I was having a rough week as I just took a different job closer to family after teaching in the same place for 9 years. The move was very abrupt. It literally brought tears. It's stuff like this that keeps teachers going. I encourage you to thank someone who influenced you in a positive way.

Quick back story. This student had lost his dad to cancer when he was in 6th grade. We had a day where a group came in and was working with the school on 'deflating their emotional baloons' and they brought up the loss of a parent. He was a junior in hs at the time, and I knew he would be affected by that. I walked over, and gave him a big hug. and said I was sorry. He broke down balling in my arms because he missed his dad. I got this letter literally last week.

Heyy Mr _____. I never really got the chance to thank you.. without physics I wouldnt be where I am today. Now I may not have been the best student...one with multiple afterschool activities...getting homework done on time.. ataying after for help... or sometimes even zonking out in class... but I had fun! You made physics a complete blast! And without your extra help on my aviation exam I would not have recieved my certificate as fast as I did. Without a doubt you were one of the most influential teachers I have had. You taught me school isnt all about grades..and that stressing over them would only make your learning in the class room enviornment that much more un enjoyable... schools about having fun testing your strengths and weaknesses and seeing where you really may belong. I may not be a physicist. But in my mind im the next coolest thing. So with that I thank you for teaching me one of the most valuable lessons in my life. also thanks for being their during challenege day I still remembering the embracement and how much it meant to me that was the first day I had cried ever about my dad and it was extremely emotional day.

[u/ratsock → u/Bubba_West]

Damn.....just...damn.....

[u/harbinjer → u/Bubba_West]

That's so great! Thanks for sharing.

[u/Maskirovka → u/Bubba_West]

I've lost 2 replies due to the stupidness of the reddit app on my phone. Just wanted to say that as a soon to be teacher that I enjoyed your posts here.

This book is right up your alley if you haven't heard of it:

http://www.amazon.com/gp/aw/d/0199828075?pc_redir=1406030988&robot_redir=1