D. How was Velcro discovered? Related: Mangoes Round the Year - Expla...
How was Velcro discovered?
Velcro, a fastening system that consists of two strips of fabric, one with tiny hooks and the other with tiny loops, was discovered through a combination of observation and curiosity.
1. The Inspiration
In 1941, a Swiss engineer named George de Mestral went on a hunting trip with his dog. After returning home, he noticed that both he and his dog were covered in burrs, tiny seeds with hooks that easily stuck to clothing and fur. This incident sparked his curiosity and led him to understand the mechanics behind burrs' ability to cling to surfaces.
2. The Investigation
George de Mestral examined the burrs under a microscope and discovered that they contained tiny hooks that latched onto the loops in fabric or animal fur. Intrigued by this natural fastening mechanism, he decided to replicate it artificially.
3. The Experimentation
De Mestral began experimenting with various materials to recreate the hook-and-loop system. He eventually settled on using nylon, a strong and durable synthetic fabric. He designed one strip with thousands of tiny hooks and another with thousands of tiny loops that would interlock when pressed together.
4. The Success
After several years of trial and error, de Mestral successfully created what we now know as Velcro. He named it by combining the words "velvet" and "crochet" to describe the fabric's soft texture and hook-like features.
Mangoes Round the Year - Explanation (Hindi)
1. Introduction
Mangoes are a popular and delicious fruit that is typically associated with the summer season. However, advancements in technology and agricultural practices have made it possible to enjoy mangoes throughout the year.
2. Improved Cultivation Techniques
Farmers have adopted improved cultivation techniques to extend the mango-growing season. They use methods such as high-density planting, pruning, and grafting to increase the productivity and yield of mango trees. These techniques allow for multiple harvests in a year.
3. Controlled Environment
In regions where mangoes are not traditionally grown, controlled environment agriculture (CEA) is used to create ideal conditions for mango cultivation. CEA involves growing mangoes in greenhouses or indoor farms where temperature, humidity, and lighting can be controlled to mimic the natural growing conditions.
4. Hybrid Varieties
The development of hybrid mango varieties has also contributed to mangoes being available year-round. These hybrids are bred to have desirable characteristics like disease resistance, early maturity, and extended fruiting periods. By growing different hybrid varieties, farmers can ensure continuous mango production.
5. Global Sourcing and Transportation
With the expansion of global trade and transportation networks, mangoes can be sourced from different countries and regions. This allows consumers to access mangoes from areas where they are in season, even when local availability is limited.
6. Preservation and Processing
To make mangoes available