Math CentralQuandaries & Queries


Question from linda, a parent:

I'm getting married We are having a sand ceremony The empty bottle we are using holds 800ml.I have bags of colored sand each bag is 30g. There is 7 people participating in this ceremony .What I need to find out is how many grams of sand i need for 7 people to participate to fill this jar.

Congratulations on your wedding,

The answer to your question depends very much on the density of the sand in the bags. I looked at Mass, Density or Specific Gravity of Bulk Materials, a site in the UK and found that the density of dry sand is 1602 Kg/m3 . There are 1000 grams in a kilogram, 100 centimetres in a metre and one cubic centimetre is a millilitre so the density of dry sand is

The bottle holds 800 ml so you need 1.602 * 800 = 1282 grams to fill the bottle. Since there are 7 people who will participate this is 1282/7 = 183 grams each.

Since each bag weight 30 grams, dividing 183 by 60 means each person will need 6 bags of sand.

I hope this helps,

PS: Email us a photo of the ceremony if you feel inclined. We'd love to add it to this page. Best wishes!

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