When the air is heated inside the balloon, it expands, causing it to be lighter than the surrounding (and presumably) cooler air. One imagines however, that as the air inside the balloon is heated, some air is forced out (due to expansion), thus resulting in a decrease in the entire apparatus' overall mass (not to mention a decrease in mass due to any fuel's having been used to heat the air in the balloon).
The volum is similar, the mass is different.
When the heater is turned off, the air inside the balloon cools down, causing it to contract and the volume of the balloon to decrease. This decrease in volume creates less lift, causing the balloon to descend.
When you leave a balloon in the freezer overnight, the air inside the balloon cools down and contracts, causing the balloon to shrink. The particles in the air inside the balloon lose kinetic energy and move more slowly, resulting in a decrease in pressure and volume inside the balloon.
Yes, air is a mixture of gasses (roughly 80% nitrogen, 20% oxygen, with small amounts down to traces of carbon dioxide, water vapor, neon, argon, krypton, radon, carbon monoxide, methane, sulfur dioxide, hydrogen sulfide, various nitrogen oxides, etc.). Air has mass & weight. Air occupies a volume of space. Air moves and you feel it when it does (i.e. wind).
A syringe is similar to a balloon in effect on pressure. The more air you insert, the less space for fluid. The more pressure exerted on it, the less volume of air and the more the liquid would fill up the space.
If the volume of the air inside a balloon increases while the mass remains constant, the density of the air inside the balloon will decrease. This means that the air inside the balloon will become less dense.
The air will expand, increasing the volume
No, the mass of the deflated balloon is the same as the mass of the inflated balloon, as the only thing that changes is the volume and density of the air inside the balloon.
If the volume of the balloon doubles while the mass of helium remains the same, the density of helium inside the balloon would decrease by half. Density is calculated as mass divided by volume, so if volume doubles and mass stays the same, the density will decrease.
As a balloon rises in the air, the volume or size of the balloon increases. This is because the atmospheric pressure decreases as the balloon gains altitude, causing the air inside the balloon to expand and the balloon to inflate.
The volume of air inside a balloon decreases as the balloon is deflated or contracts. This is because the space available for the air to occupy shrinks as the balloon's surface area reduces, causing the air molecules to be more densely packed.
When air inside a balloon is heated, the molecules move faster, causing the air to expand and the balloon to inflate. The total mass of the air inside the balloon remains the same, but the density of the air decreases as it becomes less compact.
as is, a rock, because density is mass over volume and a hot air balloon has a lesser/similar mass (stuff) but is spread out (volume) more than a rock.
You need to measure the mass using appropriate equipment. You can measure the volume of a textbook and a container of milk by measuring its linear dimensions and calculating the volume. It is not at all easy to measure the volume of an air balloon. You cannot use displacement of a fluid (water) because when submerged, the balloon would be experiencing water pressure and so would occupy a smaller volume. You cannot measure it by allowing the air to escape and measure that volume of air because that air will no longer be experiencing the pressure exerted by the material (rubber?) of the balloon. I have no answer to this part. Once you have the mass and volume, the density is merely mass/volume.
No, the mass of a blown up balloon remains the same as the mass of the empty balloon. The only thing that changes is the distribution of air inside the balloon, which may affect its volume and density.
If you decrease the volume of a fixed mass of air inside a balloon by squeezing it, the molecules inside become more crowded, leading to an increase in air pressure. You can demonstrate this by inflating a balloon and then squeezing it - the balloon will become harder as the volume decreases, showing an increase in air pressure.
The volum is similar, the mass is different.