# What is Inertia for Kids?

What is Inertia for Kids?
Inertia is a nice and easy physics lessons for kids and children. In physics, inertia is part of Isaac Newton’s First Law of Motion simply stating that a particular object at rest will stay in that state unless otherwise a force is put on it for the object to move. And similarly, inertia also involves the state of moving objects and that these objects will continue to move unless some force will make it stop moving.

In common application, inertia calculates the amount of resistance of a particular object to a change in velocity or to the objects’ momentum. For a moving object for example, momentum refers to the measurement of how hard or how easy it is to stop the object from moving. In scientific terms, momentum takes into consideration the mass of the object and this is multiplied with the speed or velocity of movement. Using this formula, the greater the mass and speed of the object is, the harder will be the force to make it stop. Like when you think of cars, bigger cars like trucks and SUVs will have greater mass and will require more force to stop it when compared with smaller cars. Not to mention that speed is also taken into account. The faster the car is moving – the greater force is also required to stop it.

For kids, an easy example to demonstrate inertia would be objects that they can relate to, like a starfish. Though starfishes can crawl pretty slowly at the bottom of the ocean floor, most kids see them as just “non-moving” animals. So using starfish as an example, one can tell kids that the starfish will remain on the bottom of the ocean floor unless some force will make it move somewhere else like on the shores. When kids see starfishes on the shores, it can be explained to them that the waves and force of the water brought the starfish from the bottom of the ocean to the shore line. The starfish would have “stayed at rest” at the ocean floor if not for the waves. And similarly if not for the sand on the shoreline, the starfish would have continued to float and move on water.