Liquid density...help required!

[Ocean Breeze]

Hi I am trying to think off the cuff quickly here, so if anyone has any ideas that would be SO helpful.

I am trying to quickly put together a liquid density column, for a junior class... its a sideways extension to the lessons they have already completed .
They have been looking at matter, solids liquids and gases, and also density.
I have a few dems for them , but thought that they could do a prac in making a density of liquids column. No measurements or calculations, just something pretty so that they can see some different liquids settle out at different levels in a tall glass measuring cylinder.

I need at least 3 liquids that will form bands.Different densities of liquid.
I thought that I could use cooking oil, water, and ?
I could either colour the water with food colouring to make it different, or colour the oil with sudan III. I tried metho, but it just mixes with the water.
Anything that is both hydrophobic as well as fat-phobic? :-k

Please any ideas, I have to draw up the lesson plan soon!

[J]

Just a stab in the dark, because you're in a hurry - Kerosene? - Diesol?

Julie

[J]

I just found this and plagiarised from another site. Maybe it's what you need. Good luck.

Julie

Density layers/floating demonstrations:
1. Gas jar with layers set up as follows:
Pink tinted meths as the top layer
Paraffin Oil
Green coloured water
Honey at the base
Then, gently drop in a marble which will sink to the bottom.
Followed by a 10c coin which sits on top of the honey.
Then a piece of Perspex (cut up biro tube) which sits on top of the water.
Then a piece of flat plastic which sits on top of the paraffin oil.
Finally a polystyrene ball which floats on top of the meths.
2.Set up a jar with marble-glycerol (or golden syrup)-perspex (acrylic)-water-candle wax-paraffin (or olive oil)-small dob of petroleum jelly-methylated spirits-wood.
3. Use a strong copper sulfate solution eg saturated, with kerosene on the top and 3 ping-pong balls. Two of the ping-pong balls have been filled with a certain amount of lead shot. So, one ball will sink to the bottom, one will float in between the copper sulfate & kero and the unweighted ping-pong will sit on top of the kero.
Firstly with the ping-pongs, the empty one should weigh ~2.13g and will float on top of the kero. The other two I filled with very small lead shot (2mm diameter) by drilling a very small hole in each and filling one to a total weight (ball plus shot) of 32.49g and the other 24.42g. Seal with Araldite.

[Jazz]

Hi,
Use table this website it has density for heaps different chemicals chose one
http://us.mt.com/mt/filters/application ... 05d031.jsp

[Ocean Breeze]

YOOZ are big SHOOOGE geniuses. I am about going off by head here... SO many things going on at once!
I have decided to trial the honey, coloured water, paraffin oil/(or canola depending) and a bit of kerosene on top. Have the densities from table, and so have a rough idea of what layers will settle at.
Will let you know how it goes.
Ta Guys!

[RosalieM]

try using glass tubes instead of a measuring cylinder. we have just finished doing this with year seven. we used glycerine, salt water, tap water and metho with a different colour in each. put one end of the tube in a piece of potato and use droppers (i found the disposable pipettes worked best). the kids had to work out the order to put them in the tube by trial and error. the teacher demonstrated the technique using the same substances but with different colours so the kids couldnt just copy. you have to make sure the liquid runs down the side of the tube rather than straight into the previous layer. You can also use different concentrations of salt solutions to do this as well.
Rosalie

[souj]

Hi Rosalie,
What diameter glass tubing do you use and where might I get something like that?
Thanks,
Jodie

[Ocean Breeze]

I had one class run yesterday with my set-up. Went well. We used large test tubes, clamped on a retort stand. Teach & I pured the honey in 1 st, so that it didnt stick to the sides on the way into the tube. The students then poured in colured water, then paraffin oil, then blue kero last.
They then dropped in small pieces of lead, zinc, plastic and wood.
I gave the teacher a list of the densities of all the liquids and solids that we used, so they could think through their observations

[RosalieM]

They are about 5mm diameter on the inside. I'm not sure where the tubes came from. I only started this year and they already had them. I think they are the same glass tubes that are used in stoppers in test tubes etc. Someone else might know where to get them from.
Rosalie

[souj]

Thanks Rosalie. I only ask because I'm after some rigid transparent tube with a diameter of approx. 50mm- sounds like what you are using is much too small for my needs. Thanks for answering anyway!

[RosalieM]

I just noticed some glass tubing in the Q Stores catalogue while I was looking for something else. I don't know what diameters it goes up to but it was under General Glassware - Tubing. This information may not be of any use to you but thought I'd pass it on anyway.
Rosalie