Albert Einstein theoretically proposed the existence of gravitational waves in the year 1915.

They are thin strands of wire made of shape memory alloys. They can contract by 5% when electric current is passed through them.

The scales on the wings of a morpho butterfly contain nanostructures that change the way light waves interact with each other, giving the wings brilliant metallic blue and green hues.

Manipulation of colours by adjusting the size of nano particles with which the materials are made.

The constituent particles of atom are called sub atomic particles. Therefore electron, proton and neutron are sub atomic particles. Later it was understood that protons and neutrons are made up of quarks. These quarks are also sub atomic particles. Recently it is discovered that the Higgs particles or God particles give mass to many particles like protons, neutrons etc.

Advantages of Robotics:
(i) Robots are more precise and error free in performing the task.
(ii) Robots never get tired like humans. It can work for 24 x 7. Hence absenteeism in work place can be reduced.
Disadvantages of Robotics:
(i) Unemployment problem will increase.
(ii) Robots can perform defined tasks and cannot handle unexpected situations.

(i) The scales on the wings of a morpho butterfly.
(ii) Peacock feathers.

(i) Gravitational waves are the disturbances in the curvature of space-time and it travels with speed of light.
(ii) Any accelerated charge emits electromagnetic wave.
(iii) Similarly any accelerated mass emits gravitational waves but these waves are very weak even for masses like earth.
(iv) The strongest source of gravitational waves are black holes. The discovery of gravitational waves made it possible to study the structure of black holes since it is the strongest source of gravitational waves.
(v) In fact, the recent discoveries of gravitational waves are emitted by two black holes when they merge to a single black hole.
(vi) In fact, Albert Einstein. theoretically proposed the existence of 'gravitational waves' in the year 1915. After 100 years, it is experimentally proved that his predictions are correct.

There are two ways of preparing the nanomateials, top down and bottom up approaches

(i) Particle physics deals with the theory of fundamental particles of nature and it is one of the active research areas in physics.
(ii) Initially it was thought that atom is the fundamental entity of matter.
(iii) In 1930s and it was established that atoms are made up of electrons, protons and neutrons.

(i) Nano-robots in blood stream to perform small surgical procedures, to fight against bacteria, repairing individual cell in the body.
(ii) It can travel into the body and once after the job is performed it can find its way out. Chinese scientists have created the world's first autonomous DNA robots to combat cancer tumours.

The innovation in medical diagnosis has taken leaps and bounds due to integration of technology and basic physics. A few of such advancements are discussed below:
Virtual reality :
Medical virtual reality is effectively used to stop the brain from processing pain and cure soreness in the hospitalized patients. Virtual reality has enhanced surgeries by the use of 3D models by surgeons to plan operations. It helps in the treatment of Autism, Memory loss, and Mental illness.
Precision medicine (or) customised health care :
In this approach, individual variability in genes, environment and life style for each person are aken into account for disease treatment and prevention. Hence, it is possible to customise health care. Medical decisions, treatments, practices or products and others are tailored to the individual patient.
Health wearables :
It is a device used for tracking a wearer's vital signs or health and fitness related data, location, ete. Medical wearables with artificial intelligence and big data provide an added value to healthcare with a focus on diagnosis, treatment, patient monitoring and prevention.
Artificial organs :
An artificial organ is an engineered device or tissue that is implanted or integrated into a human. It is possible to interface it with living tissue or to replace a natural organ. It duplicates or augments a specific function or functions of human organs so that the patient may return to a normal life as soon as possible.
3D Printing :
Advanced 3D printer systems and materials assist physicians in a range of operations in the medical field from audiology, dentistry orthopedics and other applications
Wireless brain sensors :
Wireless brain sensors monitor intracranial pressure and temperature and then are absorbed by the body. Hence there is no need for surgery to remove these devices.
Robotic surgery :
Robotic surgery is robotically assisted surgery helps to overcome the limitations of pre-existing minimally-invasive surgical procedures and to enhance the capabilities of surgeons performing open surgery.
Smart inhalers :
Inhalers are the main treatment option for asthma. Smart inhalers use bluetooth technology to detect inhaler use, remind patients when to take their medication and gather data to help guide care.

a) Human Robot :
Robots are made to resemble humans in appearance and replicate the human activities like walking, lifting, and sensing, etc.
The important part of human Robots are :
(i) Power conversion unit : Robots are powered by batteries, solar power, and hydraulics.
(ii) Actuators: It converts energy into movement. The majority of the actuators produce rotational or linear motion.
(iii) Pneumatic Air Muscles : They are devices that can contract and expand, when air is pumped inside.
(iv) Muscle wires : They are thin strands of wire made of shape memory alloys. They can contract by 5% when electric current is passed through them.
(v) Sensors: Generally used in task environments as it provides information of real-time knowledge.
(vi) Electric motors : Different types of motors are used. The most often used ones are AC motor, Brushed DC motor, Brushless DC motor, Geared DC motor etc,. They are used to actuate the parts of the robots like wheels, arms, fingers, legs, sensors, camera, weopons, systems, etc.
(vii) Robot locomotion : It provides different types of movement to the Robot. They are,
(a) Legged.
(b) Wheeled.
(c) Combination of Legged and Wheeled Locomotion.
(d) Tracked slip/skid.
(viii) Controller : lt is known as the "brain" which is run by a computer program. It gives commands for the moving parts to perform the job.
(vi) Piezo Motors and Ultrasonic Motors : It is used for industrial robots.
(x) Artificial Intelligence : The artificial intelligence is introduced into robots to bring in human like behavior in robots. Now they work on,
(a) Face recognition.
(b) Providing response to player's actions in computer games.
(c) Taking decisions based on previous actions.
(d) To regulate the traffic by analyzing the density of traffic on roads.
(e) Translate words from one language to another.
b) Industrial Robots :
There are six types of industrial robots.
(i) Cartesian.
(ii) Selective Compliance Assembly Robot Arm (SCARA).
(iii) Cylindrical.
(iv) Delta.
(v) Polar.
(vi) Vertically articulated.
Again six-axis robots are ideal for Are Welding, Spot Welding, Material Handling and Machine Tending and other applications. They can work for 24 x 7, stronger and faster than humans. However, humans cannot be replaced by robots in decision making.

The key components in Robots are power conversion unit, actuators, controller, sensors, manipulators and necessary software. 
The following diagram clearly explains the functions of the key components.
Most Robots are composed of 3 Main parts:
i) The controller:
It is known as the 'brain' which is run by computer program. It gives commands for the moving parts to perform the job.
ii) Sensors:
It tells the robot about its surroundings. It helps to determine the sizes and shapes of the objects around, distance between the objects and directions as well.
iii) Mechanical parts:
It makes the robot to move, grab, turn and lift. It consists of motors, pistons, grippers, wheels and gears.

Advantages of robotics:
(i) The robots are much cheaper than humans.
(ii) Robots never get tired like humans. It can work for 24 x 7. Hence absenteeism in work place can be reduced.
(iii) Robots are more precise and error free in performing the task.
(iv) Stronger and faster than humans.
(v) Robots can work in extreme environmental conditions: extreme hot or cold, space or underwater. In dangerous situations like bomb detection and bomb deactivation.
(vi) In warfare, robots can save human lives.
(vii) Robots are significantly used in handling materials in chemical industries especially in nuclear plants which can lead to health hazards in humans.
Disadvantages of Robotics:
(i) Robots have no sense of emotions or conscience.
(ii) They lack empathy and hence create an emotionless workplace.
(iii) If ultimately robots would do all the work, and the humans will just sit and monitor them, health hazards will increase rapidly.
(iv) Unemployment problem will increase.
(v) Robots can perform defined tasks and cannot handle unexpected situations.
(vi) The robots are well programmed to do a job and if a small thing goes wrong it ends up in a big loss to the company.
(vii) If a robot malfunctions, it takes time to identify the problem, rectify it, and even reprogram if necessary. This process requires signi cant time.
(viii) Humans cannot be replaced by robots in decision making.
(ix) Till the robot reaches the level of human intelligence, the humans in work place will exit.