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.
If the hole is larger, it is difficult to seal. If too large, place a small square of paper over the hole, then seal with Araldite.
Before sealing, you might want to test the weights first by sealing temporarily with blu-tack and dropping them in the liquids.
You may have to change the weights a little to suit.
In a 1000mL measuring cylinder pour in approximately 370 mL of copper sulfate solution (Relative Density approximately 1.10) and gently pour in the kerosene. Drop in the heavy one first…then the second heaviest…..and so on….(there is not enough room in the measuring cylinder to drop them in reverse). Label them 1, 2 and 3.

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