Compare what happens with the red dye in the water bin with what happens to a hot air balloon surrounded by cool air.
In both cases, the phenomenon of convection is observed, but the processes are slightly different:
1. Red dye in a water bin: When red dye is dropped into a water bin, it spreads and dissipates throughout the water due to the process of diffusion. Although the dye molecules move in all directions, the process is relatively slow and random. The mixing occurs because of the unequal concentration of dye molecules in different parts of the water, aiming to achieve equilibrium.
2. Hot air balloon surrounded by cool air: A hot air balloon works based on the principle of convection. The air inside the balloon is heated, and since hot air is lighter than cool air, it tends to rise upwards. This movement creates an upward draft, causing the balloon to ascend. As the balloon rises, it encounters cooler air, which causes the heated air inside to expand and become less dense. This expansion displaces the cooler air, allowing the balloon to maintain its buoyancy and stay afloat.
In summary, the red dye in the water bin disperses due to diffusion, while in the case of a hot air balloon surrounded by cool air, convection occurs, causing the hot air to rise and displace the cooler air.