Just keep your mouse over the glass and it will disappear. When it glows, it disappeared. Nothing really happens after that.
The Dancing Feet Spell is currently not usable on Pottermore. However, it most likely corresponds to Tarantallegra, a spell Draco Malfoy uses on Harry in Chapter 11 of Chamber of Secrets.
Chapter Fourteen - Cornelius Fudge.
The title of chapter 9 in Harry Potter and the Chamber of Secrets is 'The Writing on the wall'. The topics in it are Mrs Norris, Filch's cat, being found petrified and there being writing on the wall in blood. There is more to it but I suggest you read the whole book in order to understand it properly.
In chapter 8 on the top stair
Curses and Countercurses is in Chapter 12, Moment 2 (Christmas at Hogwarts), lying on the bench.
Chapter 5 of Harry Potter and the Chamber of Secrets was released on the 18th September 2012.
You don't interact with the diary in this chapter.
Chapter 5-11 were released on the 18th September 2012.
The hairpin is collected in chapter 4 of Harry Potter and the Chamber of Secrets in the moment titled "Lucius Malfoy". It can be found in the hair of the blonde girl.
You have to click on the spells coming from the wands. They are identified by the colours.
It is open now, you should be able to access it so long as you have finished the previous chapters.
You have to catch as many pixies as possible (up to 10) within 50 seconds.
The Dancing Feet Spell is currently not usable on Pottermore. However, it most likely corresponds to Tarantallegra, a spell Draco Malfoy uses on Harry in Chapter 11 of Chamber of Secrets.
Chapter 5 was locked for a long time as it had not been released. It should be open now, if you still can't access it make sure you have completed chapter 4.
The baked bean flavoured Bertie Bott's bean can be found in the moment "Harry's Escape" which is the first moment of Harry Potter and the Chamber of Secrets chapter 3.
Mudbloods and Murmurs
The Worst Birthday