Or have you walked on a gravel path? Maybe you had a headache and had to take ... Scientists classify any collection of small ...

Or have you walked on a gravel path? Maybe you had a headache ... hard particles—such as puffed rice, sand grains or pills—as a granular system. Even though everyone has interacted with ...

Or have you walked on a gravel path? Maybe you had a headache ... hard particles – such as puffed rice, sand grains or pills – as a granular system. Even though everyone has interacted with ...