Space

Unit Review Sheet

Facts and Definitions

Lesson 1: Our Solar System

• A system is made up of parts that interact to function as a whole.
• The atmosphere is a thin layer of gases that protects us from the heat and radiation of the Sun.
• An ellipse is the shape of an oval.
• The planets of our solar system are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
• An astronomical unit is 93 million miles, the distance from Earth to the Sun.
• Our solar system is in the Milky Way galaxy.
• The Earth rotates (spins) on its axis — this takes one day (24 hours).
• The Earth revolves around the Sun — this takes one year (365 days).

Lesson 2: The Sun

• The Sun is the largest object in the solar system and is a giant ball of gas.
• A solar eclipse occurs when the Moon moves in front of the Sun and the day becomes as dark as night. You can even see stars in the middle of the day.
• The Sun is made up of 70% hydrogen and 28% helium.
• The gravitational pull of the Sun and inertia help keep the planets in orbit.
• Daytime occurs when a geographical location is hit by the rays of the Sun.
• Nighttime occurs when the rays of the Sun do not hit a geographical location.
• The seasons are determined by how directly the Sun's rays hit a geographical location.

Lesson 3: The Moon

• The Moon orbits the Earth.
• The Moon does not emit light but reflects light from the Sun.
• The Moon influences the ocean tides on Earth.
• The lunar cycle is one complete orbit of the Moon around the Earth and is characterized by the Moon's different phases.

Lesson 4: What Else Is in Space?

• A constellation is a group of stars that is said to resemble an animal, object, or mythical character.
• A galaxy is a collection of stars, gas, and dust.
• An asteroid is a small celestial body made up of rock that orbits the Sun.
• A meteoroid is a small chunk of an asteroid, piece of comet, or dust that burns within the Earth's atmosphere. Once it enters the atmosphere, it is known as a meteor and is seen as a falling or shooting star. Meteor chunks that hit the ground are known as meteorites.
• A comet is composed mainly of dirt, gas, and ice and travels in an elliptical orbit. Comets look like they have tails when they are close to the Sun.
• A dwarf planet orbits the Sun but is much smaller than a planet.

Lesson 5: Exploring Space

• Russia and the United States have the most advanced space programs in the world.
• NASA stands for National Aeronautics and Space Administration.
• Sally Ride was the first American woman to go into space.
• Neil Armstrong was the first man to walk on the Moon in 1969.
• John Glenn was the first American to orbit our planet.

Final Project: A Tour of the Solar System

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