Electricity flows easily through metal wires. Copper, aluminum, and silver are good conductors of electricity. Electricity can also flow easily through some salt, acid, or alkaline solutions. When electricity flows…
Electromagnetic radiation is made from two sorts of energy— electrical and magnetic. As the radiation moves outward from its source, its energy constantly changes from strong to weak and back…
Before scientists discovered how to generate electricity, people had to use other sources of energy. For centuries, people burned wood or coal to heat their homes and cook their food.…
There are two kinds of electrical charge—positive and negative. An object that gains electrons has a negative charge. An object that loses electrons has a positive charge. Two charges of…
A battery may have just one cell or more than one. Many flashlight batteries, have only one cell. Each cell is made up of three main parts. Do you know…
The baby in the picture hasn't been born yet. It is still lying inside its mother's womb.How could a photograph like this have been taken? The photograph was taken using…
Nothing we know of can travel faster than light. An object traveling at the speed of light can travel around the world about seven and a half times in one second.The…
When you look around your home, you will see lots of different colors. Most people like to have plenty of color in their home. Colors can make a room look…
Shut your eyes tight—all you can see is darkness. Now open your eyes again. If it is daytime, you will see that light is all around you. What is Natural…