What are groups of hundreds to billions of stars held together by gravity called?
Galaxies
100
This is a piece of rock from a comet or asteroid that enters Earth's atmosphere.
Meteor
100
Seasonal changes are caused by the ______ of a planet's axis and its revolution around the sun.
Tilt
100
In the Metric System, what are the base units for measuring volume, mass and meter?
Liter, Gram and Meter
100
This is when a solid gains heat and becomes a liquid.
Melting
200
Our sun is a ____________ sized star. It is the closest star to Earth. It is just one of many start in the galaxy known as the _______________.
What is medium and Milky Way.
200
This is a meteor that hits Earth's atmosphere.
Meteorite
200
Stars are born by the gravitational attraction of gases in a ______________.
Nebula
200
A ____________ is something that is kept the same throughout an experiment. A ______________ changes.
Control, variable
200
This is when a liquid loses heat and becomes solid.
Freezing
300
Stars are spinning clouds of mostly ____________ and __________ that radiate ______ and ________.
Hydrogen, Helium, Heat, Light
300
The greater the ___________ of an object, the greater the gravitational attraction.
Mass
300
Distances to stars are so great that they are calculated by how far light travels in a year. This unit of measurement is called a ____________ __________.
Light year
300
What is an international system of measurement based on the number 10?
The Metric System
300
This is when liquid gains heat and becomes a gas.
Evaporation
400
How many recognized constellations are there?
88
400
What do we call a revolution period that takes one object to travel around another?
A year
400
Our _________ ___________ contains the sun, planets, comets, asteroids, and natural satellites (moons).
Solar system
400
Name the 5 steps of the scientific method.
Problem, hypothesis, experiment, observation and conclusion
400
This is when a gas loses heat and becomes a liquid.