corn starch
You could increase the air pressure inside a bag by decreasing the volume of the bag, adding more air molecules to the bag, or increasing the temperature of the air molecules inside the bag.
The air pressure is the same, inside or outside the paper bag.
You can increase the air pressure inside the bag by reducing the volume of the bag or adding more air molecules to it. This can be done by squeezing the bag to decrease its volume or blowing air into the bag to increase the number of air molecules present inside.
The chip bag is sealed, and no air can get inside it. The air pressure decreases as you get higher, so the air inside the bag expands to equalize the pressure on the outside of the bag.
The mass of the bag with air will be the sum of the mass of the bag itself and the mass of the air inside it. The mass of the air can be estimated by knowing the dimensions of the bag and the density of air at the given conditions.
The bag does not collapse because the air pressure acting on the inside of the bag is equal to the air pressure outside the bag (There are the same number of air molecules per unit volume inside the bag as outside). However if you had filled the bag with air at high altitude where the air pressure is lower, then sealed it and brought the bag down to sea level you would find that the higher external air pressure (there are fewer air molecules per unit volume inside the bag than outside) would begin to compress the bag down to a smaller volume. This in turn would compress the air inside the bag leading to an increase in its pressure. This decrease in volume will continue until the air inside the bag is compressed to the point where its pressure is equal to that of the external air pressure. For further information on this topic it may be worth searching for the term "Combined Gas Law" which will explain the relation between pressure, temperature and volume.
As the bag of balloon rises, the pressure inside the bag of balloon decreases. Air pressure generally decreases as the altitude increases.
Talcum powder or baby powder is a common type of powder that is often packaged in a bag for easy application.
When the air inside a zip-loc bag freezes, it contracts and takes up less space. This can cause the bag to shrink or become more rigid. Once the air warms back up, it will expand and the bag will return to its original state.
When a sealed bag is compressed, the air inside the bag gets more tightly packed, which increases its pressure. Even though the volume of the bag may decrease due to compression, the air molecules inside become more densely packed, leading to increased pressure.
When a sealed bag is compressed and more space is available in the bag, the air pressure inside the bag decreases. This is because the air molecules are now occupying a larger volume, leading to a lower pressure.
If you blow air into a bag, the air fills the bag, causing it to expand. This increase in volume occurs because the air molecules inside the bag move apart and create pressure against the bag's walls. If the bag is sealed and you continue to blow air into it, the pressure will increase until the bag may burst if it exceeds its elastic limit. Conversely, if the bag is porous or has a hole, the air will escape, and the bag won't fully inflate.