Experiments

The card remains attached to the rim of the glass and does not allow the water to flow out is due to Atmospheric pressure. Atmospheric pressure is the force that holds the card in place. The card stays on the upside-down glass because the pressure of the air molecules pushing up on the card is greater than the weight of the water pushing down.

When the flames inside the bottle become extinguished due to lack of oxygen, the gas inside the bottle cools. This cooling causes the pressure of the remaining gas inside the bottle to become less than outside atmospheric pressure. At that point, atmospheric pressure pushes the egg inside the bottle.

Two identical balloons are inflated to different diameters and connected by means of a tube. A valve controls the flow of air through the tube. When the valve is opened, air will flow from the balloon at higher pressure to the balloon at lower pressure. The lower pressure balloon will expand. The smaller balloon has the higher pressure. So, when the valve is opened, the smaller balloon pushes air into the larger balloon. It becomes smaller, and the larger balloon becomes larger. The airflow ceases when the two balloons have equal pressur

This science experiment will demonstrate how the pressure of the air outside is stronger and that can crush a bottle.

This amazing experiment works on surface tension. Surface tension is a thin sheet or skin formed by water. Surface tension tightly holds the water molecules together. Thus, if the surface tension of the water remains undisturbed, it will be able to support the paper clip. Thus, the paper clip is not actually floating, it is simply being held on the water surface due to surface tension. Several insects such as grasshoppers and water spider use this “sheet” to walk across water.

Capillary action is important for moving water (and all of the things that are dissolved in it) around. It is defined as the movement of water within the spaces of a porous material due to the forces of adhesion, cohesion, and surface tension.

The surface tension of water molecules actually allows water molecules to bond together enough to help keep the water from leaking out of the holes in the bottle. With the help of the surface tension, and the difference of air pressure outside of the bottle and inside the bottle is why the water does not leak out of the bottle.

1. Drop the Clip :  A paper clip on the surface of water will float but if you add a drop of soap in water it sinks because the soap breaks the surface tension of water.
2. Soap Powered Paper Boat: A paper water boat can be made to move in water using soap drops as it will break the surface tension and water molecules force the boat to move.
3. Do Not Open: When we make holes in a plastic bottle full of water, the water does not drip out as surface tension holds the water but if we open the cap of the bottle, air pressure from top makes the water drip.

class 11

Centre of mass or centre of gravity determines an object's stability. If the line of action of the centre of mass falls outside of the object's base, then the object topples.

When the rice is inside the bottle, there are grains next to one another, but there is a little bit of space, an air pocket, in between each grain and its neighbor Which allows the chop stick to slide out of the bottle. When the rice is packedmore tightly, the friction between each piece of rice and its nearest neighbors increased. At some point, the friction between the chop stick, rice and bottle was so great that it is strong enough to resist slipping and pick up the bottle.