Knowing the World Around Us

Answer

The seven sense organs are: eyes (vision), ears (hearing), nose (smell), tongue (taste), skin (touch, warmth, cold, pain), kinesthetic system (body position and movement), and vestibular system (balan…

Answer

The adequate stimulus for the eye is light waves. The visual receptors—rods and cones—are activated only by light energy within the visible spectrum (approximately 400–750 nanometers). This light is r…

Answer

1. **Cornea**: Transparent front layer that allows light to enter and helps focus it. 2. **Iris**: Colored ring of muscle that controls the size of the pupil and regulates light entering the eye. 3. *…

Answer

Rods are responsible for vision in low light (scotopic vision) and detect motion but not color. Cones work in bright light (photopic vision), allow color vision, and provide sharp detail. There are ab…

Answer

Visual adaptation is the process by which the eye adjusts to different light intensities. In bright light, the iris contracts the pupil to reduce light entry. In dim light, the pupil dilates to allow …

Answer

The two main physical characteristics of sound waves are: 1. **Frequency**, which determines the pitch of the sound (measured in Hertz, Hz), and 2. **Amplitude**, which determines the loudness or inte…

Answer

The human ear can typically hear sounds ranging from 20 Hz to 20,000 Hz. Young people are most sensitive to frequencies in the middle range. Sensitivity to high frequencies decreases with age.

Answer

1. **Outer ear**: Includes the pinna and auditory canal; collects sound waves. 2. **Middle ear**: Contains the eardrum (tympanic membrane) and three small bones (ossicles—malleus, incus, stapes); ampl…