Understanding light and sight

State the device used to overcome the limitation of sight

Understanding sound and hearing

State the device used to overcome the limitation of hearing

Introduction Our human senses are limited. Especially for science our sense of vision is very limited. Much of the world and the universe is either too far away or too small for us to observe with our naked eyeballs. As we so often do, we overcome our limitations with tools (ah, technology). In 1609 when Galileo capitalized on centuries of experimentation with glass optics by popularizing a practical telescope; he not only provided something that extended the human sense of sight but also opened new worlds for us to discover – the very small and the very far away.

We’re still at it, producing the tools – scientific instrumentation – to help us extend our senses into realms that we could previously only imagine. Today we can ‘see’ billions of years into the past through powerful instruments such as the Kepler and Hubble Space Telescopes. We can also see the the incredibly small, down to the very molecules and atoms that make up our physical universe. Through many kinds of scientific instrumentation such as chromatography, tomography, and spectrometry (usually supported by computers) we explore our bodies, the chemistry of life, and many other things that are mostly unavailable to our normal senses. Inventions and improvements in scientific instrumentation frequently have major impact on research, technology in general, and ultimately may help to solve scientific mysteries and practical problems.

Limitation of sight for human

Optical illusion Blind spot Cannot see trough opaque object Not able to see too tiny objects Not able to see too distance objects too

Optical illusion

An optical illusion (also called a visual illusion) is characterized by visually perceived images that differ from objective reality. The information gathered by the eye is processed in the brain to give a perception that does not tally with a physical measurement of the stimulus source. There are three main types: literal optical illusions that create images that are different from the objects that make them, physiological illusions that are the effects of excessive stimulation of a specific type (brightness, colour,

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OBJECTIVE OF THIS PROJECT

size, position, tilt, movement), and cognitive illusions, the result of unconscious inferences. Pathological visual illusions arise from a pathological exaggeration in physiological visual perception mechanisms causing the aforementioned types of illusions

The blind spot

When the image fall on the blind spot, they cannot be seen. This is because there are no photoreceptors on it.

Optical instruments

Optical instruments used to overcome the limitation of sight.

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The Technology Devices Used To Overcome The Limitation Of Sight

MICROSCOPE

An instrument used to see objects that are too small for naked eye. The first microscope invented by Zacharias Janssen. The science of investigating small objects using such an instrument is called microscopy. Microscopic means invisible to the eye unless aided by a microscope. There are many types of microscopes, the most common and first to be invented is the optical microscope which uses light to image the sample. Other major types of microscopes are the electron microscope (both the transmission electron microscope and the scanning electron microscope) and the various types of scanning probe microscope. Magnify small organism such as fungi, bacteria, virus and all others organism which can’t be seen with naked eyes.

TELESCOPE

A telescope is an instrument that aids in observation of remote objects by collecting electromagnetic radiation (such as visible light). The main function of the telescope is see far objects in the universe such as moon.

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BINOCULAR

Binoculars , field glasses or binocular telescopes are a pair of identical or mirror -symmetrical telescopes mounted side-by-side and aligned to point accurately in the same direction , allowing the viewer to use both eyes ( binocular vision ) when viewing distant objects . Most are sized to be held using both hands, although sizes vary widely from opera glasses to large pedestal mounted military models. Many different abbreviations are used for binoculars, including glasses, nocs, noculars, binos and bins. Unlike a (monocular) telescope, binoculars give users a three-dimensional image: for nearer objects the two views, presented to each of the viewer's eyes from slightly different viewpoints, produce a merged view with an impression of depth.

PERISCOPE

A periscope is an instrument for observation from a concealed position. In its simplest form it consists of an outer case with mirrors at each and set parallel to each other at a 45 degree angle. More complex periscope, using prisms instead of mirrors and providing magnification, operate on submarines.

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Ultrasound machine

Ultrasound is an oscillating sound pressure wave with a frequency greater than the upper limit of the human hearing range (energy generated by sound waves of 20,000 or more vibrations per second). Ultrasound is used in a large array of imaging tools. Often used for medical diagnostics, ultrasound uses sound waves that are far above the frequency heard by the human ear. A transducer gives off the sound waves and reflected back from organs and tissues, allowing a picture of what is inside the body to be drawn on a screen. Ultrasound can be used to look for for medical imaging, detection, measurement and cleaning, tumors, analyze bone structure, or examine the health of an unborn baby. Ultrasonic is the application of ultrasound.

x-ray

X-radiation (composed of X-rays) is a form of electromagnetic radiation. X-rays were found to be able to penetrate through materials of light atoms like flesh. The heavier atoms like metal absorb them. A beam of high energy electrons crashes into a metal target and x-rays are produced. A filter near the xray source blocks the low energy rays so only the high energy rays pass through a patient toward a sheet of film. Along with the sheet of film, a second sheet of film prevents the scattered x-rays from fogging the picture. Calcium in bones is considered a type of metal and when photographic film is placed on the body, this allows the technician to take the picture and an x-ray is developed to solve or analyze the problem. These rays were found to be harmful to the skin and soon new ways of medical imagers were developed.

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MAGNIFYING GLASS

A magnifying glass (called a hard lens in laboratory contexts) is a two-sided convex lens is used to produce a magnified image of an object. A convex lens bends light by bringing it in one side at one angle and sending it out the other at a different angle, forming an inverted image at the focal point of the lens. The bulge of the convex lens gathers light from a wide area and condenses it so the image on the other side is sharp and bright. The distance to the place where the image forms is called the focal length of the lens. The distance between the object viewed and the lens is the focal length of the object.

If you look through the lens at the object, you'll see an image that is right-side up and larger than the original. This is because the simple lens of the magnifying glass is using the retina and lens of your eye to create a virtual image, that appears to be closer to the convex lens of the magnifying glass. Magnifying glasses used by people who need to measure using magnifying glasses put a scale over the item being measured, as in the linen tester, used by printers to check paper and colour registers, shown above. Use a measure by laying it next to the object before using your magnifying glass. The magnification of a magnifying glass depends upon where it is placed between the user’s eye and the object being viewed and the total distance between them.

Conclusion

Sight is very important for human beings to ensure their survival.with sight,human beings can differentiate danger from enemies from face reaction or action.

Limitation of hearing for human

A person with normal sense of hearing can olny detect sound between 20 Hz and 20,000Hz(hertz)

Different people have different range of hearing.As we grow older,our range of hearing decreases.

There is also a limit how far our ears is able to hear sounds from a distance.

We also cannot hear very soft sound like heartbeats.

The limitation of hearing can be overcome by using hearing aid.

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LIMITATION OF HEARING

- A person with normal sense of hearing can only detect sounds between 20 Hz and 20 000

Hz (hertz ) .

- Different people have different ranges of hearing . As we grow older , our range of

hearing decreases .

- There is also a limit to how far our ear is able to hear sounds from a distance .

- We also cannot hear very soft sound like our heartbeat .

- The limitations of hearing can be overcome by using hearing aids .

The Technology Devices Used To Overcome The Limitation Of Hearing

Stethoscope

The stethoscope is an acoustic medical device for auscultation or listening to the internal sounds of an animal or human body. It is often used to listen to lung and heart sounds. It is also used to listen to intestines and blood flow in arteries and veins. In combination with a sphygmomanometer, it is commonly used for measurements of blood pressure.

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Microphone

A microphone is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal. Microphones are used in many applications such as telephones , tape recorders , karaoke systems , hearing aids , motion picture production , live and recorded audio and engineering , FRS radios , megaphones , in radio and television broadcasting and in computers for recording voice , speech recognition , VolP and for non-acoustic purposes such as ultrasonic checking or knock sensors .

Loudspeaker

A loudspeaker (or “speaker” ) is an electroacoustic transducer that produces sound in response to an electrical audio signal input . Non-electrical loudspeakers were developed as accessories to telephone systems , but electronic amplification by vacuum tube made loudspeakers more generally useful .

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HEARING AIDS

A hearing aid is an electroacoustic device which typically fits in or behind the wearer’s ear and is designed to amplify and modulate sound for the wearer . Similar devices include the bone anchored hearing aid and cochlear implant .

EARPHONE/ HEADPHONE

Headphones are a pair of small loudspeakers that are designed to be held in place close to a user’s ears . Headphones either have wires for connection to a signal source such as an audio amplifier , radio , CD player , portable media player or mobile phone , or have a wireless receiver , which is used to pick up signal without using a cable .

Conclusion

Hearing ensure human being can enjoy different type of sound such as wind blowing,bird singing,wolf howling,dog barking and ect.

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