Welcome To My School Study
Do You Know
1. Comfortable Reading Distance – 25 cm
For a normal human eye, the most comfortable distance for reading is about 25 cm.
Why 25 cm is important:
- At this distance, the eye can focus clearly without strain
- It is called the least distance of distinct vision
Understanding:
If a book is kept too close or too far, the eyes need to work harder to focus.
Importance:
Maintaining proper reading distance helps protect eyesight and reduces eye fatigue.
Example:
Most people naturally keep books or mobile screens around this distance while reading.
2. Braille System (For Visually Impaired Persons)
The Braille system is a special method used by visually impaired people to read and write.
How Braille works:
- It uses raised dots arranged in patterns
- People read these patterns using their fingertips
Importance:
Braille helps visually challenged persons gain education and independence.
Invented by:
Louis Braille
Example:
Braille books and signboards are used in schools and public places.
3. Cones in Retina (Sensitive to Bright Light and Colours)
Cones are special cells present in the retina of the eye.
Functions of cones:
- Detect bright light
- Help in colour vision
- Provide sharp and detailed images
Working condition:
Cones work best in daylight or bright light.
Difference from rods:
- Cones → colour vision and bright light
- Rods → dim light and night vision
Example:
Cones help us identify different colours in daylight.
4. Kaleidoscope (Based on Multiple Reflection)
A kaleidoscope works on the principle of multiple reflection of light.
How it works:
Mirrors placed inside the tube reflect light many times, creating colourful patterns.
Features:
- Produces beautiful symmetrical designs
- Patterns change when the tube is rotated
Uses:
- Toys
- Decoration designs
- Art and craft inspiration
Example:
Children use kaleidoscopes to observe colourful changing patterns.
5. Reading and Writing by Visually Challenged Persons
Visually challenged persons use the Braille system for reading and writing.
Special features of Braille:
- Made of raised dots
- Read by touching with fingers
- Helps in learning languages and mathematics
Importance:
It allows visually impaired individuals to study and communicate independently.
Example:
Braille is commonly used in books, elevators, and medicine labels.