sodium metal

[trish armstrong]

hi everyone,
Today we were trying to demonstrate the reaction that sodium has when it contacts water. Well we didn't get the reaction we expected. It just sizzled around the top for a couple of minutes and nothing. We started again, same thing, we ended up doing it 6 times to the same reaction. We tried wiping all the oil off, washing the demo beaker, different amounts.
The only thing that was different to last year,hope this isn't my fault, is that I changed the oil, as it was that milky that you couldn't see the sodium in the bottle. I replaced the oil with liquid parrifin oil. Did I do this wrong? Any ideas What is wrong with my metal???? Is there something we didn't do.
Trish.
Ps. we also put phenolphthalein in water.

[RosalieM]

That's all that usually happens... But maybe try a bigger chunk? Last year a teacher did that experiment with a reasonably sized piece and it exploded. Be careful not to explode the beaker though. I think we've done it in dissection trays in the past.

[trish armstrong]

Thanks Rosalie,
We usually have a few sparks sometimes a little explosion( we only use small amounts due to risk) But today not even that. I think I was just as disappointed as the boys in the back row, Usually it's exciting to watch what sodium does.
Trish

[lada]

I use parafin to keep Na. It does not always catch a light, because it has to be just the right combination of H2 to air or O2. Maybe using a little bit bigger piece Phenolphthalien is a good indicator to show the alkalinity
Lada

[Lyn]

Hi Trish,
The reaction you described is the usual reaction. If you want to show the bursting into flames place filter paper onto the surface of the water then place a small piece of sodium (rice grain size) onto the filter paper. It takes a short while to react and should burst into flames. If you cut the sodium to expose part of the surface to the air that also helps to make it more combustible. Any sodium larger than rice grain size needs to be done outdoors in metal containers, ie large coffee tins inside metal waste paper baskets out on the oval with all the right safety precautions. It's referred to as bucket chemistry. There has been previous discussion on this topic so check other forums.
Lyn.
Look under the forum on gunpowder for the reference to safety and sodium and big bangs.

[lizzieb]

We do this in large tote trays, behind an explosion screen, and with everyone wearing safety glasses. It can take several tries before getting a good reaction (ie explosion), and often nothing happens anyway (possibly due to humidity?)
The teachers usually cut the piece a bit larger every time, and wipe it dry with paper towel. When we've done it a few times with no result, there comes a time when we all decide it's safer to give up for the day!
The phenolpthalein's a good idea, and I'm going to suggest trying the litmus paper too. Thanks guys.

[Jen1]

We get a similar reaction with sodium and then do the same with potassium which gives a lovely purple flame. It demonstrates visually that reactivity of metals in group 1 of the periodic table increase as you move down the group. Then of course the kids want to see rubidium, cesium and francium so i have to tell them they are soooo reactive that they are to dangerous for our school to have them.
I remember once seeing brainiac do a demo with rubidium which exploded a toilet (or maybe a bath, cant remember now) and think that would be a good dvd to get.

[rae]

Hi Jen,
You can access the Brainiac program through Utube. We show the kids the rubidium prac a lot. They love it and so do I.

Lorrae

[Jen1]

Thanks for the info Lorrae,
unfortunately Utube is a banned website at school , but now I know where I can get it, I will find a way!!
Cheers
Jen

[rp]

Isnt potassium banned?

[Labbie]

YES banned in DET Schools in NSW.

[cactus155]

and also Tassie Schools as far as I know

[Jen1]

As far as I am aware, Potassium hasn't been banned in WA schools, yet..........

[rodannt]

I still have Potassium in Vic.........don't know if it is banned

[Robb]

Hi All,

We need to consider the schools outside NSW when we suggest that certain chemicals are banned as this can be missleading, to others and missleading information can be used and ordered in a Court of Law.

Just be careful with that one......

Sodium metal when purchased from reputable Chemical suppliers the pieces are quite large, as a person whom has used Caesium before I stress that using Sodium must be done by trained staff and those whom understand the effect of molten Sodium as some may become projected from the reaction. Large pieces are required to make a relative good explosion those pieces I am refering to are approx 2cm square. To some of you I do understand that these can be quite large but this gives(as mentioned above) a reputable bang. With this information I suggest that you read up on the molten state of Sodium and understand its reaction before progressing with the experiment. Some people did the experiment with complacency but my information to you is that you respect the Element for what it can do and what the effects of it are during and after the experiment. 20M radius when doing this experiment will be benifical only to give you a sefe buffer for you and students. Afterall it the students safety we need to consider.

The reaction after droping it in with pieces this big will be within 5 -10 seconds as larger pieces heat and warm the water substantially faster.

I hope this has given a safe and better option to you,

Cheers,

Robb.....

[macca]

Morning everyone,

Can anyone email me through private message, the main of a company and/or Phone No. where I can purchase some Sodium. Ours was every old and had to be disposed of during renovations, as we had nowhere safe to store it. Have a good week.

[Lyn]

Macca,
Try any of the following as a source for supply of sodium metal.
Labtek Qld, Westlab Vic, Science Supply Australia Vic, Omega Scientific SA.
You must have somewhere in your Science department catalogues for some of the above science supply companies.
Ajax Finechem lists suppliers for each state on their website.
ChemSupply SA has a downloadable price list for all of their chemicals.
Happy hunting.
Lyn.

[judimas]

yesterday, while I was reading this thread, there was a loud bang in the Quad. By the time I got out of my seat to look out the window there was alot of white smoke and delighted squeals and screams from the Kids. The physics teacher had just had her first go at demonstrating the reaction between water and sodium! She wasn't expecting to get such a voilent reaction. She managed to destroy the trough that she was using One of the men teachers who also managed to have a not quite so big explosion the day before. I told him that it was his fault ...his explosion stressed the glass!
I thought that it was ironic that this should happenjust as I was reading about Sodiun

Judith
PS the bio teacher destoyed a bucket a few weeks ago with sodium. This batch must be a fairly potent brew!

[kimmy]

Yes when we do sodium we normally do it in the quad with a 1cm block - a ice cream bucket (so it does not matter if get broken) and students standing away from it with safety glasses on . this produces a big flame and a even bigger bang . Lots of screems from classes around the school and many teachers complain later on . But as I say expect the unexppected in science. It is sometimes about fun not alway theory theory theory so they say.
Oh was sodium meant to be educational I thought it was for fun (LOL)

[Rowyrow]

my painful teacher asked if we had any sodium yesterday (we don't) so she has said she will get some from a school in town that she has a special relationship with. Don't know how she is going to get it here because im not going to pick it up and drive with it in my car!!!!! ( have already written off a 3month old car on my way home from work this year) Yes sodium is fun i remember at uni down in SA we had a lake and i don't really remember why but someone from the chem department chucked a big lump of it in the lake and scared the s@%T outta all the ducks and geese!