I just had to edit. I left the E out of Daltrey!! Heresy. 
The results:
Answers given by @Cleoriff
Q1 The oldest member of The Who
I double checked about the original members as I wanted to make sure we weren't talking about The Detours or The High Numbers.
A: Oldest member - Roger Daltrey who was born in March 1944 (the same year as me) John Entwhistle was the second oldest born in Oct 1944
- correct = awarded 
Roger Daltrey born 1 March 1944; John Entwistle born 9 October 1944
Q2 The first European to land in Australia
A: Willem Janszoon (a Dutch explorer) He landed on the western side in the 1600's. (James Cook landed on the East coast in the 1700's)
- correct = awarded
William Janszoon landed on western side in 1606; Cook explored east coast in 1770 [this was the QI-type question this week]
Q3: What in geography is a Cataract?
Good job you said Geography as I know more about eye cataracts!
A: A waterfall or any fast moving water over a steep drop.
- correct = awarded
Q4) Element in the periodic table with atomic number 3?
I really, really struggled with this. I know the first 3 numbers are said to be involved in the big bang. In no particular order they are Lithium, Hydrogen and Helium. (why you couldn't give me 6, 7, or 8,
I'll never know!!)
My answer is a guess....
A: Lithium 
(I went for this as Lithium is a type of medication, a battery and the forum is powered by Lithium) Apologies to those who did chemistry, I was only involved in biochemistry..
- correct = awarded
hydrogen has atomic number 1; helium atomic number 2; lithium atomic number 3
Q5) Where was the first British Show held in 1895?
It was held at Tunbridge Wells Agricultural Show (also known as the Horseless Carriage Show)
(My dad told me his grandfather went to it)
- correct = awarded
Q6) Who was Catherine Earnshaw married to in Wuthering Heights?
A: Edgar Linton. I never liked this book, it was a nightmare of relationships!!
- correct = awarded
tricky question, as most people think it must be Heathcliffe [given Kate Bush song, although she does not sing Cathy married Heathcliffe]
Congratulations @Cleoriff - not only are you awarded , but also as you correctly answered all six questions, you are the first player to be awarded the
Silver Thinker
What a fluke that was.....Lithium was an honest guess and thought it was the one I would get wrong. 
I actually knew the first explorer as it was a quiz question I got wrong when I was in Spain (at a quiz night)
Well I can go to bed happy now...
Congratulations and sleep well @Cleoriff
I can reveal that when I was sorting out the chemistry question last weekend, I came across lithium by chance, and given it is the name of this forum provider, thought it would be a suitable question.
Fix! 
Seriously, well done @Cleoriff , the first to get all 6 correct 
Oh wow, that's impressive @Cleoriff congratulations! 
→ Access for You: Registration - Find out how to register for our Access for You service.
→ Want to chat with other fellow-minded members? Head to our Off-topic section for some interesting chit-chat.
→ Check out our Priority board for tickets & offers updates, and to discuss all things Priority-related!
→ Welcome to O2! - New to O2? Find out all you need to know to get started!
If you'd like to take part, why not register? 
@Cleoriff has shown that the Silver Thinker award can be won.
How did those playing along do? Did you find the chemistry question the most difficult or another one? Your feedback is welcome.
The White Room Thursday Quiz is open to everyone. Why not put your name forward as a contestant?
All you have to do is send me [ @Mi-Amigo ] a private message [pm] and your name will be entered into the draw made by @EmilieT . The questions cover a range of subjects and different levels of difficulty.
Next week`s questions will be chosen by me this weekend from the following categories
PEOPLE; HISTORY; GEOGRAPHY; NUMBERS; LITERATURE; OLYMPICS
[no chemistry question - in case you get chosen again @Cleoriff ]
Yes I see no Chemistry....however you have Numbers....
