Vsauce! Kevin here. Kids in the U.S. haven't always had summers off. In rural areas, they went to school in summer and winter to help during planting and harvesting while urban kids went year round.
In the mid 1800's schools shifted to a standardized fall-spring schedule, allowing for family vacations and to give relief from buildings with no air conditioning, and doctors at the time supported this, saying that summers off would also help protect kids' brains from overuse. Meanwhile, kids are getting smarter.
The "Flynn Effect," shows that IQ scores improve markedly with each generation. Professor James Flynn found that if students a hundred years ago took today's IQ test, they'd average 70. While if students today took the test 100 years ago, they'd average 130.Explanations include better healthcare, nutrition and more schooling...
"福林效应“显示每一代人的智商都有显著提高，James Flynn 教授发现，若100年前的学生接受今日的IQ测试，他们平均只有70，而今天的学生参与100年前的测试，其均值高达130，其原因包括医疗饮食条件改善及更多教育……
And the fact that people before the scientific age were often adverse to classifying things they couldn't use and didn't routinely engage in hypothetical or abstract thought. Neuropsychologist A.R.Luria tested this on a socially isolated farmer about a hundred years ago, and it went something like this.
What do a chicken and a dog have in common? Nothing? A chicken has two legs, a dog have four. Chicken have wings, dogs don't!
Okay you've explained how they're different but how are they alike? They are not? Is there one word though that you could use for both of them? Nope. What about "animal"? Would the word "animal" fit? Yes.
Online courses are commonplace now，but Sir Isaac Pitman actually established the first distance learning course in the 1840's.Pitman taught shorthand by mailing postcards to students and correcting the answers that they mailed back. In the 1920s, educational radio programs were considered textbooks in the air. And today there are over 2200 courses available online around the world for free.
今日 在线课程已十分普遍, Sir Isaac Pitman在19世纪40年代开设了首个远程学习课程，Pitman通过邮寄明信片教学生速记并批改他们邮回的明信片，在20世纪20年代,教育广播节目被视作“空中的课本“,今天,全世界共有2200多个在线课程，并且免费。
While South Korea is using robot teachers to help children with learning disabilities, a kindergarten in Switzerland is bringing education back to its roots. Literally, they have a school outside in the forest where kids attend rain or snow learning to build fires and shelters alongside their ABCs.