physics

Optical illusions are visuals that tend to be deceptive to the eye and brain.

Antonie van Leeuwenhoek first discovered microbial life in the 1600s using a simple, single lens microscope that he made himself. This video gives instructions to build your own working Leeuwenhoek microscope, including the actual lens itself, using simple materials you likely have around the house.

The blind spot in our eyes is a tiny functional area about the size of a pinhead, where the optic nerve passes through the surface of the retina. This area has no photoreceptor cells that detect light, which creates the blind spot 

Two eyes give us a wider field of vision. It also helps us perceive the depth which forms a 3D impression and enhances the ability of assessing distinct position of object.

Binocular vision is a vision formed by using two eyes where there is an overlapping field of view.

When light travels from one medium to another, the speed of its propagation changes, as a result, it ‘bends’ or is ‘refracted’. Now when light passes through a prism, it is refracted towards the base of the triangle.

When there is no water in the glass, the light from the coin experiences very little refraction and we can see the light from the penny. When there is water in the glass, the light from the coin experiences refraction (bending) and reflection (total internal reflection, TIR) such the light it is not able to reach the observer’s eyes. A small amount of refraction occurs as the light leaves the coin and travels through the bottom of the glass, then refraction occurs again as it enters the water. When refraction occurs at the side of the glass there is Total Internal Reflection because of the angle of incidence. The light ends up traveling at such an angle that we are unable to see the coin.

Total internal reflection is the phenomenon which occurs when the light rays travel from a more optically denser medium to a less optically denser medium.

Fermat's principle states that “light travels between two points along the path that requires the least time, as compared to other nearby paths.” From Fermat's principle, one can derive (a) the law of reflection [the angle of incidence is equal to the angle of reflection] and (b) the law of refraction [Snell's law].

When a ray of light travels from one medium to another medium, it changes its path because it has different speed in different media. This phenomenon is called refraction of light.

When light passes from one medium to another, say air, a glass of water, then a part of the light is absorbed by particles of the medium, preceded by its subsequent radiation in a particular direction. This phenomenon is termed a scattering of light. The intensity of scattered light depends on the size of the particles and the wavelength of the light.

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.

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.

All that is holding the two books together is friction.  This is the same force that acts to stop you sliding a book across a table. When you interleave the two books there is a small force pulling the two books together created by the spine of the book.a table.  This compressive force will create a frictional force between every place the pages are interleaved, if there are 50 interleavings a small frictional force will be multiplied by 50 to create a huge force that you can't overcome with pure muscle.

Paper helicopters spin because of the earth’s gravity, lift, and configuration of the rotors. When dropped, the helicopter’s mass experiences gravity, and it naturally falls to the floor which causes paper blades to bend slightly upward due to lift. The lift force of the air pushes on each of the blades equally but in opposite directions, horizontally and vertically. As a result of the horizontal equal, opposite, and offset forces, the helicopter spins around as it descends.

When the bottle filled with water is dropped, the water and air inside the bottle will fall at the same rate due to gravity

Gravity is the force that attracts objects towards each other and the reason that everything that goes up must come down. Because the magnetic force between the magnet and the paperclip is stronger than the force of gravity between the paperclip and the ground, the paperclip remains in the air.

 According to Newton’s third law of motion, the walls of the balloon will exert an equal and opposite reaction force on the air molecules inside the balloon. This reaction force causes the balloon to expand and become inflated.

The coin-card experiment is a classic physics experiment that demonstrates the property of inertia of rest and frictional force.

Magnetic levitation is a method by which an object is suspended with no support other than magnetic fields. The magnetic force is used to counteract the effects of the gravitational acceleration and any other accelerations.

Hooke’s law states that the strain in a solid is proportional to the applied stress within the elastic limit of that solid.

What is the floating ball in the magnetic field?

Buda Ball is a magnetically levitating sphere that hovers in mid-air. Designed to lower our stress levels, Buda Ball floats and rotates hypnotically in an invisible magnetic field, creating a soothing, time-stopping visual experience: a reminder to live in the present momen