What is a planet?
A planet is a space object that orbits a star and has a large enough mass to have its own gravity.
What is a star?
A star is a space object that can create its own light and energy due to a fusion reaction.
What is an orbit?
An orbit is the path of a space object around another object in space.
What is circular motion?
Circular motion is the motion of an object along the circumference of a circle.
What is velocity?
Velocity is the speed and direction of an object. Velocity is a vector quantity.
What is tangential velocity?
Tangential velocity is the linear component of the speed of any object at a given instant that is moving along a circular path.
What is Newton’s Universal law of Gravitation?
Newton's law of universal gravitation states that every particle attracts every other particle in the universe with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.
What is Newton’s Second Law of Motion?
Newton’s Second Law of Motion describes how the application of force can change the motion of an object. The law is summarized by the equation F = ma, where F = force, m = mass, and a = acceleration.
What is an ellipse?
An ellipse is an oval shaped figure with two foci.
What does perihelion mean?
Perihelion is the point in an orbit when a space object is closest to the object it is orbiting.
What does aphelion mean?
Aphelion is the point in an orbit when a space object is farthest away from the object it is orbiting.
What is Kepler’s First Law of Planetary Motion?
Kepler’s First Law of Planetary Motion states that the path of the planets about the sun is elliptical in shape, with the center of the sun being located at one focus.
What is Kepler’s Second Law of Planetary Motion?
Kepler’s Second Law of Planetary Motion states that an imaginary line drawn from the center of the sun to the center of the planet will sweep out equal areas in equal intervals of time.
What is Kepler’s Third Law of Planetary Motion?
What is Kepler’s Third Law of Planetary Motion states that the ratio of the squares of the periods of any two planets is equal to the ratio of the cubes of their average distances from the sun.
What is a period?
The period of a space object is the length of time to complete one orbit or revolution around the body the space object is orbiting.
What is an astronomical unit?
One astronomical unit (au) is the average distance between Earth and the sun.
Grade 3 – 5 Lesson 1 Vocabulary
Gravity – an attractive force that pulls objects together due to the masses of the objects
Planet – a space object that orbits a star and has a large enough mass to have its own gravity
Star – a space object that can create its own light and energy due to a fusion reaction
Mass – a measure of the amount of matter in an object
Force – any push or pull
Contact force – a push or pull by objects touching each other
Non-contact force – a push or pull on an object when the object is not touched by the object creating the force
Orbit – the path of an object around another object in space
Ellipse – an oval shaped figure
Constant – does not change
Speed – how fast something is moving
Tangent – a line that touches a curve that is perpendicular to that point on the curve
People have been studying the sky for ages. Observing and predicting the motion of objects in space was some of the earliest science conducted by humans. In this module, you’ll investigate how objects in our solar system move and what makes them move. Don’t space out over these lessons, get started now.
