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Answer For Diagnostic

1. R- Pain receptors, P- Touch receptors, S-

Pressure receptors

2. Sensation, regulation, or protection.

3. Thickness of epidermis, concentration of

sensory cells.

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Light

Speed of light 3.0 x 10^8 m/s

Or 300,000km/s

Can travel through vacuum (electromagneticwave) can travel without medium.

Properties of light: travel in straight line

Prove: the formation of shadow, eclipse ofsun, and eclipse of moon.

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Light Travelling in Straight Line

The Prove for light travelling in a straight line:

- the formation of shadow

- the eclipse of the sun- the eclipse of the moon

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Shadow

(A small light source dont produce

Umbra and Penumbra)

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Umbra and Penumbra

(the shadow from a large light source)

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Application of the properties of light

Sundails make use of shadows to tell time

A sundial is a device that measures time by theposition of the Sun. In common designs such asthe horizontal sundial, the sun casts a shadowfrom its style onto a surface marked with linesindicating the hours of the day. The style is thetime-telling edge of the gnomon, often a thin rodor a sharp, straight edge. As the sun moves across

the sky, the shadow-edge aligns with differenthour-lines. All sundials must be aligned with theaxis of the Earth'

http://en.wikipedia.org/wiki/Gnomonhttp://en.wikipedia.org/wiki/Gnomonhttp://en.wikipedia.org/wiki/Gnomon

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Horizontal Sundails

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The sundial dates back to the Egyptian Period,

around 1500 B.C. It was also used in ancient

Greece and Rome. In central Europe it was the

most commonly used method to determine

the time, even after the mechanical clock was

developed in the 14th century. The sundial

was actually used to check and adjust the timeon mechanical clocks until late into the 19th

century

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Transparent, Translucent, Opaque

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Stereoscopic vision

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Stereoscopic Vision Used when both eyes are used to view an object

Human beings and predators (tigers, dogs, owls,cats etc)

Animal with stereoscopic vision- both eyes in the

front of their head Advantage of stereoscopic:

To see things in three dimensions

To estimate distance accurately

Large field of stereoscopic vision

Helps predators to pounce accurately on their prey

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Monocular vision

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Monocular vision is used when we look at things

only with one eye

Herbivorous animals such as cows, zebras, deer and

horses have mainly monocular vision.

Advantage: can see a large area (to detectpredators)

Disadvantage: cannot judge distance accurately,

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Devices to Overcome the Limitations

of Sight

Eyes are not perfect, can not see in any

condition

I F i

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Instrument Function

Magnifying Glass It is a biconvex lens with short focal length

It enlarges an object for viewing

Microscope It use two biconvex lenses- the objective lens and

the eyepiece lens

It is used to magnify very tiny specimens such as

cells and microorganisms

Binoculars They are used to see objects which are far away e.g.

to watch horses running in a race

Periscope It is used by submarines to see what is above the

surface of the sea. It is also used to see things on

the other side of a wall

X-ray machine It is normally used in hospitals to take pictures e.g.

to detect any fracture in bones or injury in the body

An x-ray of the chest is taken to detect tuberculosis

of the lungs

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Ultra sound

scanning machine

It is a machine which scans the internal organs of

the body such as the gall bladder and liver

Contact lens Some people wear contact lenses instead if

spectacles to correct their eye sight

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Periscope

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Sound can travel through solids, liquids and

gases.

Sound can travel at about

5000 m/s in solids

1300 m/s in liquids

300 m/s in air

D t th ti l i lid i l l t

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Due to the particles in solid is closely compact,

the vibration of sound can be pass (propagate)

quickly from one particle to particle.

There is no sound travelling pass vacuum,

because sound need medium to propagate.