- Periscope
- Bird in the Cage
- Musical Tubes
- Shortest Path
- Wave Motion
- Colour Disc
- Sympathetic Swing
- Double Cone
- Lever Mechanism
- Advantages of Pulley
- Gyroscope
- Sun Dial
- Echo Tube
- Archimedes Pump
- Angular Momentum
- Newton's Wheel
1. MECHANICAL ADVANTAGES BY PULLEYS
Pulleys are simple machines used to gain mechanical advantage in lifting heavy loads. The
simplest pulley system consists of a single pulley wheel and a rope. While this basic setup does
not increase the lifting force.
To increase the lifting force, a more complex system involving two or more pulleys can be used.
In this setup, one pulley is fixed to an overhead beam, while the others are attached to the load.
This arrangement is the foundation of a system known as a "block and tackle." The blocks refer
to the pulleys and the tackle refers to the rope. The effort required to lift the load is significantly
reduced if the amount of rope that needs to be pulled increases proportionally.
2. ARCHIMEDES PUMP
The Archimedes pump also known as the Archimedes screw is a simple machine designed to
raise water from a lower level to a higher level. This ingenious device converts kinetic energy
into potential energy, enabling the efficient transport of water against gravity.
The Archimedes pump operates through a rotating spiral tube which is positioned at an angle
within a cylindrical casing. As the tube rotates, the centrifugal force generated by this motion
causes water to flow upward through the spiral. This continuous rotation lifts the water from the
lower end of the tube to the higher end, effectively raising the water level.
3. BIRD IN A CAGE
The Bird in a cage illusion is a fascinating demonstration of the phenomenon known as
persistence of vision. This effect occurs when pictures of a bird and an empty cage are pasted on
opposite sides of a metal sheet, which can be spun around a vertical axis using a handle fixed at
the base. When the metal sheet is spun at low speeds, the bird and the cage are seen separately,
alternating in succession. However, when the sheet is spun at a sufficiently high speed, the
observer perceives a steady image of the bird inside the cage. This optical illusion is due to the
persistence of vision where the human eye retains an image for 1/16 th second after it has
disappeared.
4. COLOUR DISC
The Colour Disc model is a captivating demonstration that illustrates how different colours
absorb heat differently. This simple yet effective model with sections painted in various colours.
By exposing the disc to a source of heat, you can observe how the colours react differently to the
heat, providing insights into the principles of heat absorption.
When the disc is exposed to a source of heat, such as sunlight, the colours absorb the heat at
different rates. Darker colours, such as black, absorb more heat compared to lighter colours, such
as white.
5. DOUBLE CONE
When you place a double cone at the narrow end of a 'V' shaped rail, it starts moving towards the
wider end, giving the illusion that it is moving uphill. However, this is not the case. The key to
understanding this phenomenon lies in the centre of mass of the double cone.
At the narrow end of the rail, the double cone’s centre of mass is elevated. As the double cone
moves along the rail towards the wider end, it appears to rise, but in fact, its centre of mass is
descending. The double cone effectively sinks into the 'V' shaped path resulting in a downward
motion of its centre of mass. This descent is in line with the law of gravity which states that
when an object is unsupported, it will move in a way that lowers its centre of mass.
6. GYROSCOPE
A Gyroscope demonstrates the principles of angular momentum and rotational stability. A simple
gyroscope model is constructed with a bicycle wheel with handles and a chair. The handles are
attached to the bicycle wheel for easier spinning ensuring the wheel can spin freely. When the
wheel is spun, it demonstrates angular momentum. Sitting on the chair hold the bicycle wheel
and have someone spin it rapidly. Lift your feet off the floor and tilt the wheel. The chair will
turn in the opposite direction of the tilt due to the conservation of angular momentum. Tilting the
wheel in different directions will cause corresponding movements of the chair.
7. LEVER MECHANISM
A Lever model consists of a beam of different lengths. The heavy load is attached at one end. By
applying a small force (effort) over a greater distance at the other end, the lever can lift the large
load.
8. WAVE MOTION
A wave motion model demonstrates the fundamental principles of how waves travel through different
mediums showcasing the behaviour and properties of waves in a visually and physically engaging
manner. This model can depict a variety of wave forms such as longitudinal and transverse waves
as well as how they interact with their surroundings.
The wave motion model typically consists of a series of connected elements such as metal tubes
arranged in a line. These elements can move to simulate the motion of particles in a medium
through which a wave travels.
9. SUN DIAL
A sundial is an ancient timekeeping device that uses the position of the sun to indicate the time
of day. It operates on the principle of the sun casting a shadow on a marked surface with the
position of the shadow correlating to the time. A sundial consists of curved plate known as the
dial and a stick. The stick is positioned pointing towards the celestial pole. As the sun moves
across the sky, the stick casts a shadow on the dial. The position of this shadow on the marked
dial indicates the time of day.
10. PERISCOPE
A periscope is an instrument for observation over, around or through an object, obstacle or condition that prevents direct line-of-sight observation from an observer's current position. A periscope works on the basis of laws of reflection of light. Any object in the line of sight reflects the light making it visible in the periscope.
The mirrors are placed at an angle of 45° such that when light falls on one of the mirrors it gets reflected back making it fall on the other mirror which further gets reflected back to the observer’s eyes.
11. ECHO TUBE
Reflection of sound is a phenomenon where sound waves upon encountering a barrier, bounce back towards their source. This effect commonly known as an echo. It can be demonstrated through a simple model using pipes.
To hear a clear echo of a sound, there must be a minimum time lag of 1/10th of a second between the original sound and its echo. Here, we have used tubes of 18 meters length. Given that the velocity of sound is 340 meters per second, the sound wave travels a total of 36 meters (18 meters each way). The sound wave takes more than 1/10th of a second to travel this distance and return to our ears resulting in a clear echo in this tube.
12. NEWTON’S COLOUR DISC
The Newton’s Colour Disc is a fascinating demonstration of the principles of colour mixing and the composition of white light. This device consists of a rotating disc painted with seven distinct colours. When spun rapidly, it provides a visual representation of how white light is composed of various colours.
13. SHORTEST PATH
The cycloidal path demonstrates that a ball travelling along this path reaches its destination faster than one on a straight path due to the gravity effect. The cycloid is the curve that minimizes travel time between two points.
There are two path one is cycloidal path and a straight-line path. Place two balls at the top of the paths and release them simultaneously, though the cycloidal path is longer than the straight-line path, the ball released in the cycloidal path reaches the bottom first. The ball in the cycloidal path gains more initial acceleration due to gravity than in the straight-line path so it reaches the bottom first.
14. ANGULAR MOMENTUM
The operation of this device relies on the principles of centrifugal force and rotational inertia. It features a rotatable platform with a circular rim and a centrally positioned seat on a vertical axis. On either side of the seat, two rods hold smoothly movable weights. When the device is set to rotate at a high angular speed, the person holding the weights experiences a centrifugal force pulling the weights outward.As the weights slide outward the rotational speed decreases. Conversely, when the weights are pulled back towards the body the rotational speed increases. The moment of inertia is greater when the weights are farther from the axis, resulting in a slower spin. When the weights are brought closer to the axis, the moment of inertia decreases, causing the angular speed to increase.
15. SYMPATHETIC SWING
This is based on the principle of coupled resonant pendulums. One of the pendulum is pulled back some distance and let go. As it swings back and forth, observe that the other pendulum also begins to move picking up speed and amplitude with each swing. Notice that the originally moved slows down with each swing and eventually stops, leaving the second pendulum briefly swinging by itself. Then the process begins to the second one is stopped. The motion is transferred back and forth between the two until them come to a halt eventually because of friction.
16. MUSICAL TUBES
Musical tubes are instruments that uses the basic concept that, the pitch of any vibrating material being inversely proportional to the length of the same. This concept is used in string instruments as well. The role of a musician is to control these variables in order to produce a given frequency from the instrument that is being played.
A set of pipes of varying lengths are suspended at top. Each of them produces sound of a particular pitch, when the pipes are struck one by one gently. The pitch produced depends on the length of the pipe. Longer the pipe, lower the pitch. When the pipes are struck, the air molecules inside of them vibrate, producing the sound.