sieves

[strewth]

Hi all
I need to find some way to grade marble chips into 3 or 4 sizes for surface area comparisons.
There must be some cheap and cheerful way to achieve this without buying expensive graded sieves. I'd appreciate any ideas, thoughts, supplier info.
Thanks in advance
Ruth

[RosalieM]

We just do this experiment (if I'm thinking of the right thing) using marble chips and calcium carbonate. Well, they are both calcium carbonate, but one is a fine powder and the other is the marble chips. The kids use acid to compare the different reaction rates between the different surface areas. The powder produces a lot more gas. If you need 3 or 4 'grades' I'd go for 3. Use the calcium carbonate powder, the marble chips, and then roughly crush a few of the marble chips into smaller pieces as the middle sized chips. I hope this helps and I have the right idea of what you were asking

[ELIZABETH]

We do this one with soluble aspirin - so much easier.

[strewth]

Thanks Rosalie
That might work for what our guys want. Just wanting a quick easy separation of sizes !!
Cheers
Ruth