GRAVITATION AND WEIGHTLESSNESS: BASIC SCIENCE: WEEK 9

By the end of the lesson, students should be able to:

Explain the meaning of gravitational pull and weightlessness.
outline the effects of the gravitational pull
describe the effect of gravitation pull on stone, feather, and book.

GRAVITATION AND WEIGHTLESSNESS: BASIC SCIENCE: WEEK 9

MEANING OF GRAVITATIONAL PULL AND WEIGHTLESSNESS

Gravitational Pull:

Gravitational pull, also known as gravity, is the force by which a planet or other body draws objects toward its center. It is the reason why objects fall to the ground when dropped. The strength of gravity depends on the mass of the object exerting the force and the distance between the objects. The more massive the object, the stronger its gravitational pull.

Weightlessness:

Weightlessness, or zero gravity, is the sensation experienced when there is no force of gravity acting on the body. This typically occurs when an object or person is in free fall, such as astronauts in space orbiting the Earth. Although gravity is still acting on them, they are in a continuous state of free fall, creating the sensation of weightlessness.

GRAVITATION AND WEIGHTLESSNESS: BASIC SCIENCE: WEEK 9

Effects of Gravitational Pull

Gravitational pull has several key effects:

Keeps Planets in Orbit: Gravity is the force that keeps planets in orbit around the sun and moons in orbit around their planets.

Formation of Stars and Planets: Gravity is crucial in the formation of stars and planets, pulling together gas and dust to form these celestial bodies.

Tides: The gravitational pull of the moon causes ocean tides on Earth.

Human Physiology: Gravity affects human bodies, influencing blood circulation and muscle and bone density.

Projectile Motion:

Objects thrown or propelled follow a curved trajectory due to the gravitational pull.

Effect of gravitational pull on stone, feather, and book

The gravitational pull acts on all objects equally, but the effects observed can differ due to factors like air resistance.

STONE:

When a stone is dropped, it falls quickly to the ground because it is relatively dense and heavy. The gravitational pull acts on it strongly, and because it has a high mass, it experiences less air resistance relative to its weight, allowing it to fall rapidly.

FEATHER:

A feather falls much more slowly than a stone due to its lower mass and higher surface area relative to its weight. Although the gravitational pull on the feather is the same, air resistance significantly slows its descent. In a vacuum, where there is no air resistance, a feather would fall at the same rate as a stone.

BOOK:

A book falls similarly to a stone but might experience a bit more air resistance due to its flat shape and larger surface area compared to a stone. However, it will still fall relatively quickly because of its higher mass compared to a feather. Like the stone, the gravitational pull on the book is significant, and air resistance only slightly affects its fall.

Gravitational pull is a universal force acting on all objects, causing them to be attracted towards the center of the Earth or other celestial bodies. Weightlessness is experienced when this gravitational force is not felt, such as in free fall. The effect of gravity on different objects varies due to their mass and the resistance they encounter from the air.