Raj is standing on the edge of a cliff that overlooks a valley, facing towards the horizon where the sun is setting. He is holding a helium-filled balloon with a string that is not tied to his wrist. If Raj releases the balloon, what will happen to the balloon and why? Respond very briefly.
The balloon will rise upwards and away from Raj. Helium is lighter than air, so the buoyant force caused by the surrounding air is greater than the gravitational force acting on the helium balloon, causing it to ascend. Since Raj is standing at the edge of a cliff and there is likely to be an airflow rising along the cliff face, the balloon may also drift away horizontally from Raj, carried by the upward breeze. Additionally, if there is any wind blowing in the direction of the sunset, the balloon will be pushed further in that direction.