What is the difference between html and html5 :)

HTML5 comes with some new features that didnt exsit in previous versions or sometimes it redifines some attributes that exsited before.HTML5 contains much better support for media such as, an audio and video tag ,in fact there is a cool feature here called preload.
the preload feature makes you have a fully loaded vedio upon the loading of the page .HTML5 supports local storage while lesser versions dont ,this feature allows advanced browsers to remember what u input in fields even if u close the browser or if u refresh it.one of the important features that emerged with html5 is the ability to use sectioning in your web page,as this can help you improve the document structure;sectioning is made easier in html5 by the elemnts that appeared in html5 like article,header,footer,aside.
html5 provides you of a support of regular expressions which can make validating forms a much easier process.
and ofcourse there are many many new elements that appeared in html5 and there are many elemnts that got obsolete  I highly recommned here the use of HTML5 cheat sheets as I really benifted from using them when I started learning HTML5, you can find them all  over the internet.

HTML5 is a newer version of the HTML coding language. At the same time, it is more advanced, with new features and changes to improve it. For the most part, both are same. If you know how to code in any older versions of HTML, for the most part you should be good in writing HTML5. But HTML5 has several goals which differentiate it from HTML4. More....HTML and HTML5

Here is the one liner:   

 

HTML5 is responsive :) used to design UI for tablet and mobile - case close

 

Few bullet points:

Upgrade of HTML specification

Symantic markup - giving meaning to markups

Native support for audio,video, geo location, Canvas

Made flash and other 3rd party redundant, because of the navtive feature

Support for devices

and many more.. basically the future of web.

• HTML & HTML5 are diffrent version of the markup language .
• Canvas : As the power computing is increasing day by day .People want load page faster and faster ,In coneventional method inorder to display something dynamicaly is done on server side and send to client as image .Dynamic image drawing was not possible .In HTML5 it use technique called canvas to draw web graphics  .Introduction of canvas lead to webbrowser game develoment 
• Video Tag : Now problem lies with videos  .more video player started to come in picture  .each webprovider satrted to use diffrent player , client browser need many plugin to watch the video . Inorder to standerdize in HTML5 introduced video tags .Now no need of plugin video player to play the video
• Input Field Verification : Usualy for input field verifcation javascripts are used that is an over head for the programmers aswell as to the  client as additional dailogs ,messed up codes.HTML5 introduces many additional fields to reduce such implementation . 

Some elements like , , are added to html5 which makes it easier to design webpages for video and audio content.
html5 is much more easier to learn.
here in html5 we dont need to mention the html version which we are using and the type(text/html).
u can design2d and3d graphics.
actually html5 is much more than this.

HTML is a markup language but HTML5 is new, there is no big difference in both of them.
HTML5 have some tags and attributes which his descents can't interpret

The best reference would be the W3 Consortium You will find there everything you need documented about the language, changes and differences from other versions: