How do you calculate the percentage of air in sand?

Well from what I have learnt. You can find out by doing an experiment. Add 100 cm3 of sand to a measuring cylinder then add 100 cm3 of water. Shake it up and measure the solution with the cylinder. To find the air percentage just put the result over 200 and divide it by 100% and that's your air percentage.

I'm not sure how accurate this is but bear in mind I'm just an 11th grader trying to get through Biology. Hope this helped.