we have two really quite unusual elements

which you might not have seen before.

We have Osmium (76)

which is one of the few metals that's blue

and this is a very beautiful crystalline example.

if you look (at it), it sparkles

as you move your head.

Osmium is one of the densest metals.

It has arguably the highest melting point.

There is some argument whether it's Iridium (77) or osmium. They are very close together

and they are both very high.

The other element is the hardest one to get hold of

of any element up to Uranium (92)

and this is Thorium, which is element number 90.

So, this was a present from Max Whitby

and Theo Gray

who are specialists in preparing samples of the elements.

Thorium is particularly hard to transport.

You can't send it through the post, because it's radioactive,

so they gave it to me and I brought it back to Nottingham in my pocket.

I was slightly worried that there might be anti-terrorist radiation-meters,

but I think the plastic is sufficiently thick that you can't get any radiation out from it.

We'll be making a video quite soon about Thorium,

but it's quite interresting. The sample here are more wires

than a lump

and it's a slight black-ish colour which quite surprised me.

The Osmium was a present from a fan.

I was at a conference

and he jumped up from the audience as I was walking through and said 'I have a present for you'

and whipped out some Osmium from his pocket.

I was amazed!

For day ten, we have two really exciting elements: Osmium; Thorium,

day nine: periodic table handkerchief,

a charred piece of wood,

seven: a fan from a fan,

six: element carbon,

five: a glowing plectrum,

four drinking vessels,

three chemical badges,

two periodic table bedcovers,

and one piece of tartaric acid from a Swiss wine barrel.

Let's see what we get for day eleven.

[Professor Mike Merrifield] ...cluster, so a pair of stars in tight orbit around one another.

The Sun then encounters this binary star.

One of the things we know about those --

what are called "free body encounters," so a binary star

has a third star coming into it -- is that the third star can

get kicked out at high speed. And in fact, typical speed

you'd expect the sun to get kicked out at in that case

is around 20 kilometres per second!