The four principles pertain to selection of the narrative format, the fleeting nature of spoken words, the environmental soundscape, and the difference between listening and hearing. These four principles are relevant to designers seeking to use only sound (audio) for instructional delivery.

There are three primary types of experimental design: Pre-experimental research design. True experimental research design. Quasi-experimental research design.

The purpose of the experimental research strategy is to establish the existence of a cause- and- effect relationship between two variables. To accomplish this goal, an experiment manipulates one variable while a second variable is measured and other variables are controlled.

Sound is a form of mechanical energy that travels in a longitudinal wave in a series of compressions (high pressure) and rarefactions (low pressure). The transmission of sound requires a medium such as air, liquid, or tissue.

Basic Sound Principles. Sound is a form of energy similar to light, which travels from one place to another by alternately compressing and expanding the medium through which it travels.

Sound is the transfer of energy from a vibrating object in waves that travel through matter. Properties of sound include speed, loudness, and pitch. The speed of sound varies in different media. The loudness of sound depends on the intensity of sound waves. The pitch of sound depends on the frequency of sound waves.

The basic properties of sound are: pitch, loudness and tone.

Properties of sound are speed, loudness, and pitch.

squeal

List three characteristics of shadow

• It depends on the shape of the object.
• It depends on the source of light whether it is plane parallel rays or spherical.
• It depends on the position of the object whether the object is at an infinite or finite distance.
• It depends on the position of the source of light.

Characteristics of a shadow :

• It depends on shape of the object.
• It depends on source of light whether it is plane parallel rays or spherical.
• It depends on position of the object whether the object is at infinite or finite distance.
• It depends on the position of source of light.

1) It depends on shape of the object. The shadow increases and decreases in the ratio same as the shape of the object. 2)It depends on source of light whether it is plane parallel rays or spherical. 3) It depends on position of the object whether the object is at infinite or finite distance.

Shadow: Opaque objects do not allow light to pass through them and cast dark patches behind them. These dark patches are called shadows….Characteristics of a Shadow:

• It is always black, regardless of the colour of the object used to make the shadow.
• It only shows the shape or outline of the object and not the details.

(1) There should be an opaque material. (2) There should be a source of light and screen. The object must be placed in the path of light. Then shadow is formed on the screen.

In a pinhole camera, image formed is inverted because the object is between radius of curvature and focus. What is the path of light? Answer: Straight line.

Light: Light is a form of energy which helps us in seeing objects. When light falls on an object, some of the light gets reflected. The reflected light comes to our eyes and we are able to see an object. Luminous Object: An object which produces light is called a luminous object, e.g. sun, bulb, etc.

The path of light is straight and the velocity of light is constant in uniform composition material such as glass. The path and the velocity of light changes when light enters another material such as air or water. The path of light can undergo many changes as light goes from its source to your eye.

From the cornea, the light passes through the pupil. The iris, or the colored part of your eye, controls the amount of light passing through. From there, it then hits the lens. This is the clear structure inside the eye that focuses light rays onto the retina.

Light travels in a straight line until something alters its path. Here are three ways light’s path can be altered: it can be refracted, reflected, or absorbed.

Light passes through the front of the eye (cornea) to the lens. The cornea and the lens help to focus the light rays onto the back of the eye (retina). The cells in the retina absorb and convert the light to electrochemical impulses which are transferred along the optic nerve and then to the brain.