০৬
Hand in Hand
Why anything sticks to anything else. Chemical bonds from the electron outward — salt, water, diamond and DNA all explained by the same idea.
97 pagesEnglish + BanglaFree
Download
📚 E-Books Featured
Science for Young Readers · ০৪
A River Inside the Wire
Electricity from the atom to the power station, in 141 pages and 54 chapters — with an interactive edition whose figures you can actually pull apart.
Editions
Free to read and free to share — in families, in schools, in reading circles.
English interactive edition
English · HTML · 141 pages · 3.2 MB
English edition (PDF, for print)
English · PDF · 141 pages · 3.7 MB
Bangla interactive edition
Bangla · HTML · 141 pages · 3.4 MB
Bangla edition (PDF, for print)
Bangla · PDF · 141 pages · 3.9 MB
This edition runs in your browser — drag the sliders, build the circuits, watch the figures move.
Highlights
- Interactive edition — 18 figures you can drag, build and break
- 141 pages, 18+ hand-drawn figures
- Bangla and English editions
- Free to read, free to share — at home, in school, in reading circles
- Written for class 7–8, and for any adult who was never shown the picture
About this product
What this book is about
Everyone knows electricity flows through a wire. Almost nobody can say what is actually moving, or why a thicker wire helps, or where the energy in a battery was sitting before it became light. This book answers all of that from the ground up, and it takes 141 pages to do it properly.
It starts inside the atom, with the electron that nobody can see, and ends at a power station with a turbine the size of a house. In between: charge, current, voltage, resistance, Ohm's law, circuits in series and parallel, magnetism, induction, generators, transmission, and finally the wall socket in your own room. Fifty-four short chapters, each about two pages, so no single idea is ever asked to carry more than it can.
The metaphor the title borrows — a river inside the wire — is used carefully and then deliberately broken. Water is a good picture of current right up to the moment it becomes a lie, and the book says exactly where that moment is. That honesty is the point.
The interactive edition
This volume is the first in the series to ship twice: as a printed-page PDF, and as a self-contained interactive edition that opens in your browser. In the interactive version, eighteen of the figures are alive. Drag a slider and watch Ohm's law rebalance in front of you. Build a circuit and see where the current goes. Change the field and watch the induced current change with it.
Both editions come from a single source, so the words and the figures are identical — the interactive one simply lets you push on them. It needs no internet connection once loaded and nothing is installed.
What is inside
- The atom, the electron, and what "charge" physically means
- Current, voltage and resistance, each with a picture you can test
- Ohm's law, built rather than stated
- Series and parallel circuits, and why your house is wired the way it is
- Magnetism and induction — the trick that makes generators possible
- From the power station to your wall socket
- Activities, a numbers table, a glossary, a quiz and the sources
Built with
BanglaSVG figuresHTML → PDFInteractive
More from this series
View details
০১
A Brain in a Glass Bowl
Living brain cells, grown in a dish, learning to play a video game — and what that tells us about thinking itself.
41 pagesBanglaFree
Download
০২
Letters Made of Light
Every star you look at is a letter posted years ago. This book is about how big the universe really is — and why small does not mean unimportant.
73 pagesBanglaFree
Download