Hazel: Hi, everyone.
I'm so excited to say that I'm with Emilia at Sancton Wood School,
and we're going to be bringing Science with Hazel to the lab.
So we'll be showing you lots of practicals.
Emilia is going to introduce herself.
Emilia: Hi. My name is Emilia. I am a lab technician.
I work in this school, Sancton Wood School in Cambridge.
I am also stem ambassador,
which means I go in other schools to introduce science to the kids, and we have a lot of fun together.
I have also an Instagram page, @emilia.science,
and follow me to see all my experiments and videos.
Hazel: Yeah, you should absolutely follow her.
Emilia: Thank you.
Hazel: It's awesome.
In this video, Emilia and I are going to be testing for positive ions.
So it's effectively a flame test which proves which metal you have.
You hold the various samples in the Bunsen burner,
and dependent on the colour the flame turns,
you can use that to identify which metal.
So, from an exam point of view, you might need to provide a method,
and so your flame test method is to use a clean nichrome wire,
which you're going to dip in hydrochloric acid
to make sure it's doubly clean.
Then you place the sample on the nichrome wire.
And the crucial thing is that
the Bunsen burner needs to be a roaring blue flame.
And you can hear it roaring.
(roaring)
However, because we're in a lab, there's actually a slightly easier way for us to do that.
So don't worry that our method is slightly different.
The colours will still be exactly the same as the ones you need to state,
but try and list the method that I've just described.
Emilia: There are several ways in which you can perform this.
Usually, I do it soaking the splint in a solution of ethanol for some hours,
and then I dip the splint in the powder.
So, this one is copper chloride.
Hazel: Here's our roaring blue flame.
(roaring)
Wow.
Oh, my goodness.
And that fantastic green-blue colour is due to the copper ions present.
Gosh, that's amazing. I like that.
Second one ...
it's lithium chloride this time.
And this is a wonderful colour.
Look.
Hazel: So, with lithium, we can see this very characteristic crimson colour.
Emilia: Third one is potassium chloride.
Hazel: Potassium, this is burning with a beautiful lilac flame.
Try and remember for me that when you have potassium in cold water,
it produces a lilac flame,
and when you burn potassium in a flame test, it also produces a lilac flame.
Emilia: [Fourth] one is sodium chloride.
Hazel: So, regular table salt now.
Yeah, we get a lovely orange-yellow flame here.
Emilia: And last one is calcium chloride.
Hazel: Calcium chloride burns with a brick red orange flame.
And do you make sure you learn these colours nice and accurately,
as well as that simple method I described at the beginning.
(music)
