Our year 7 will be doing a practical assessment task which includes a station on density. The plan is to have a sealed container with Kerosense, Olive Oil, water and mercury layered and then add a marble . I'm a bit nervous about setting this up for a number of reasons including spillage/breakages, and then disposal/ clean up. Am I warranted in my worry??
Does anyone have any suggestion regarding an alternative density test like this? Or should I just not worry??
Hi Lorrae, try this for your density column:
Shampoo, Oil, Vinegar ( coloured RED), Detergent, Metho ( coloured blue) & Glycerol.
Pour the above solutions into a measuring cylinder or test tube and watch the changes.
You will end up with the different leves
Hope this helps
Narelle Divola
You can use a large measuring cylinder and an egg. Use either sugar or salt to make up a strong enough solution to float the egg. Test glycerine, oil, sugar/salt waterand metho and carefully drop the egg in. It should float somewhere in there!
For our density prac we use golden syrup, water and oil to which we add a couple of jelly beans, wing nuts, lego blocks and peanuts. This works well. The teacher handles the peanuts.
How do the teachers think you are going to dispose of that???? That prac seems like it has come out of one of those text books that you find covered in dust and written in black and white, typed manually You know the kind I mean.
Tell them to get with the 21st century, no one uses mercury like that anymore.
Re Mercury:
Its important to ask the teacher if you can have a look at his/her Risk Assessment for this prac, before you begin to prepare
If its you that completes the Risk Assessment for this prac, then I assume that once you check the hazards of Mercury, you will not use it as part of the density column.
In other words, dont use mercury!
Over the years I have used coloured canola or cooking oil , also coloured oil(oil soluble food dyes eg chocolate dyes) , same with water. I use golden syrup, honey, kerosene, glycerine.
One I use from year to year is
add honey( or golden syrup) carefully to the bottom(as it sticks to the glass), then water (colour the water with a drop of red food colouring)then parrafin oil, and lastly add kerosene.
If you want to have more fun with the column,
Then carefully add
a piece of plastic (small fingernail sizes) from an white ice cream container lid .
1 piece of expanded poystyrene
1 piece of lead shot
1 piece of zinc foil
1 piece of blue tac
1 piece of cork
1 piece of copper foil
1 piece of wood (twig, paddlepop stick , balsa etc)
1 grain of wheat
1 unpopped and one popped popcorn
the list goes on really.
Its just to give them an idea that there are varying densities all around us
AND you can enjoy the show without worrying that you will have to deal with the mercury afterwards!
WHAT!!!!!
As I read it I wondered where this teacher has been for the last 10 years!!
This prac is a definite NO-NO
maybe this teacher needs a refresher course in the new regulations ..or something more immediately painful!
I will be going with something along the lines of your suggestions I just need to find something that will sit above the bottom layer so will be playing with that. I have heeps of time as it's not until week 8.
Hi All
I am going to show my ignorance here, where do I buy dyes that colour oil? It was mentioned about chocolate dyes?
We have a prac this afternoon with coloured water, coloured saturated salt solution and coloured oil.
I was thinking of leaving the oil the yellow it is (Coles Vegetable Oil).
I generally leave the oil un-coloured as well. The colours are only to highlight the different layers so the yellow helps it stand out. Other than chocolate colouring the only thing I can think of is the sudan stain which is used in senior classes for testing foods for fats and oils. It is red.
I raced home at lunch and grabbed some powdered food dye. Tried mixing with acetone before adding to two litres oil and it changed colour. Thanks for the tips. Fingers crossed for last period.
You know the kind I mean.
