Gulliver’s Nutrition
Why did the King of Lilliput serve 1728 meals to Gulliver? This is because the volume of two objects that resemble each other in three dimensions is proportional to the cube of length. Since Gulliver’s height … more
Serial Parallel Circuit 3
Resistance Electrical resistance is a property of a material that impedes the flow of electric current. The unit of resistance is the ohm(Ω). When a voltage of 1V is applied, the conductor’s resistance that allows a … more
Dissolution Process
Dissolving Dissolving means that the solute diffuses into the solvent and mixes. It is a common case that salt or sugar is dissolved in water. Solvents are often liquid, mostly water. The Earth’s atmosphere is a … more
Rectifier Circuit
Diode Diodes are electronic components that pass current in only one direction. The direction in which current can flow through the diode is called ‘forward,’ and the direction in which current cannot flow through the diode … more
The principle of LED
LED LEDs are electronic devices that emit photons. LEDs have higher efficiency and longer life than bulbs. Basically, LEDs have a structure like a p-n junction diode. The p-n junction diode is made by attaching a … more
Spring Scales
A spring scale is a tool that measures the mass and gravity of an object using the spring’s elastic force. The spring of this scale is lengthened by gravity and shortened by elasticity. You can find … more
Why the smaller the cell, the larger the area
Cell division Multicellular organisms like humans are made up of cells of varying shapes and functions. Most cells are so small that they can see them only under a microscope because once they reach a certain … more
Wrinkles in living organisms
Respiratory organ To maintain life, we absorb oxygen from the air. And we export carbon dioxide from the body. Human respiratory organs include the nose, organs, bronchi and lungs. Each bronchus in the lung continues to … more
Conservation of Mechanical Energy
Potential energy The potential energy of an object is the energy stored in an object or system. Denoted as Ep. Generally speaking, potential energy refers to potential energy caused by gravity and is proportional to an … more
Potential energy due to gravity
Potential energy due to gravity Lifting heavy objects increases the potential energy of the object. The amount of work done when lifting an object of mass m by height h can be obtained as (Potential energy … more