no
Modern hot air balloons do not have sand bags because the air input is easily controlled for lift. Hot air balloons used to have sandbags to weigh them down until lift off and sand was gradually dumped to gain height in the air.
Sand is porous, so air get get through it, but mud can keep air out.
The brick falls faster through the air than loose sand because each grain of sand has to overcome air resistance which is proportionally larger for the small particles.If you put both brick and sand into the same size box then they will fall at the same rate.
I think water,sand and air
Sand is made form a mixture of mineral grains (mainly quartz or calcite) which are themselves compounds. If there is water or air flowing though the sand at a fast rate, then it can also be a suspension.
rock + water= sand
I think you mean why does hot sand heat the air by convection... The sand is heated by the sun, and the air is touching the sand, which is hot, so by convection, the sand is heating the air.
stone and air
Yes, sand has a lot of air in it. That is why when you pour water on sand, the water goes right through it.
air
because in air there is heat and in sand its dark and cool
Sand is heavier than air, so it won't remain in the air forever.
air+rock
Modern hot air balloons do not have sand bags because the air input is easily controlled for lift. Hot air balloons used to have sandbags to weigh them down until lift off and sand was gradually dumped to gain height in the air.
Sand helps aerate (introduce air into and leave pockets for air) into soil.
Sand is porous, so air get get through it, but mud can keep air out.
you add air with rock Air +Rock