Any gas which is less dense than air. Even hot air will suffice.
Helium is a lighter element compared to air, helium also has fewer molecules than air.
There are actually a number of ways to make a balloon lift, without helium. Hydrogen is even less dense than helium (but has the disadvantage of also being highly flammable). And since hot air is less dense than cooler air, you can lift a balloon just by heating air. Since hot air is less expensive than either helium or hydrogen, that is a popular technique.
Anything less dense than air (hydrogen, helium, hot air).
chips
To lift 400 pounds, you would need approximately 74.3 cubic feet of helium. Helium is lighter than air, so it provides lift when contained in a balloon.
There are actually a number of ways to make a balloon lift, without helium. Hydrogen is even less dense than helium (but has the disadvantage of also being highly flammable). And since hot air is less dense than cooler air, you can lift a balloon just by heating air. Since hot air is less expensive than either helium or hydrogen, that is a popular technique.
because helium has less density
Helium balloons float down due to the weight of the balloon being greater than the lift force generated by the helium inside. As the helium inside the balloon slowly leaks out over time, the lift force decreases, causing the balloon to float down.
Helium gas is commonly used to make balloons float because it is lighter than air and creates lift. The helium gas in the balloon is less dense than the surrounding air, causing the balloon to rise.
a helium balloon is forced upward by buoyancy. a object is forced upward by a force equal to the weight of the fluid it displaces. this also applies to gases. the gas helium is lighter than average atmospheric air, that is that equal volumes of atmospheric air and helium do not weigh the same. This means that the volume displaced by the balloon is heavier than the balloon itself. since the air weighs more it applies more force upwards on the balloon than the balloon applies downwards on the air, therefore it rises. However, a helium balloon will not go down unless a force such as large air resistance (heavy wind etc.) is applied to it. hope this helps.
Yes, a balloon that is half-filled with air and the other half with helium will float because helium is lighter than air. The helium will cause the overall density of the balloon to be lower than the surrounding air, resulting in it floating.
The helium weighs less than air- so when the balloon is filled, it displaces the heavier air, and floats. Just as a bit of wood weighs less than water, and floats on water. In a vacuum, a helium filled balloon would not float (but it may pop)