Vocabulary #10 (Stars)

Definitions:

1. star: a large, hot ball of gases, wich is held together by gravity and gives off its own light
2. parallax: the apparent shift in an object's location when viewed from two positions
3. light-year: the distance light travels in a year
4. constellation: a number of stars that appear to form a pattern
5. magnitude: the brightness of a star
6. nebula: a cloud of gas and dust in space
7. supernova: a star that explodes
8. black hole: a object whose gravity is so strong that light cannot scape

Sentences and illustrations:

1. Stars are at different distances from Earth.

2. The closer the star is, the greater the parallax.

3. Astronomers use the light-year unit to describe the distances in space.

4. For example, Rigel is a star in the the constellation Orion.

5. The word magnitude is used to describe the brightness of a star.

6. A star begins its life as a nebula.

7. A supernova is a star that explodes.

8. When a star colapse it becomes a black hole.

Vocabulary #9 (The outer Solar System)

Definitions:

1. comet: a ball of ice that orbits the Sun
2. meteroid: a small asteroid (rocky object that orbits the Sun), wich may be far out in the solar system or close to the inner planets
3. meteor: a meteroid that enters Earth's atmosphere and burns with streak of light
4. meteorite: any part of a meteoroid that reaches Earth's surface

Sentences and illustrations:

1. Comets come from the outer fringes of the solar system.

2. Meteoroids are often called small asteroids.

3. We usually see the meteor as a bright streak of light.

4. Meteorites are usually classified into three types.

Vocabulary #8 (The inner Solar System)

Definitions:

1. planet: a large body orbiting a star, such as the Sun
2. solar system: a star, such as the Sun, and all the objects orbiting it
3. asteroid: a rocky, metallic object that orbits the sun
4. Kepler's laws: laws that summarize the movement of the planets

Sentences and illustrations:

1. We can detect planets from the sunlight reflected off them.

2. The solar system is the Sun and all of the planets, moons, and other bodies travel around it.

3. Asteroids are too small to be considered planets.

4. The astronomer Johannes Kepler stated three laws that summarize the motion of planets (Kepler's Laws).

Vocabulary #7 (The Moon in motion)

Definitions:

1. phase of the moon: the shape of the lighted part of the Moon seen from Earth at any time
2. lunar eclipse: a blocking of a view of the full Moon when the moon passes into Earth's shadow
3. solar eclipse: a blocking out of a view of the Sun when Earth passes through the Moon's shadow
4. tide: the regular rise and fall of the water level along a shoreline

Sentences and illustrations:

1. The phase of the moon that you see depends on the position of the Sun, the Moon, and Earth with respect to each other.

2. Twice a month the Moon crosses the plane of Earth's orbit, when this takes place at full moon  the Moon might pass through Earth's shadow; this causes a lunar eclipse.

3. For a solar eclipse to occur, the Moon must be in straight line between the Sun and Earth.

4. Tides are caused by the pull of the Moon's gravity on Earth.

Vocabulary #6 (Earth and the Sun)

Definitions:

1. rotation: a complete spin on axis
2. International Date Line: the 180 degrees line of longitude
3. standard time zone: a belt 15 degrees wide in longitude in wich all places have the same time
4. revolution: one complete trip around the sun

Sentences and illustrations:

1. It takes about 24 hours for Earth to make one rotation.

2. The International Date Line was created as the location where a new day begins.

3. There is 1 hour difference between time zones that are next to each other.

4. Earth takes 365 1/4 days to revolve, or travel on its orbit, once around the sun.

Vocabulary #4 (How inclined planes work)

Definitions:

1. inclined plane: a straight, slanted surface that is not moved when used
2. screw: an inclined plane wrapped around a central bar
3. wedge: one or a combination of two inclined planes that is moved when is used
4. compound machine: a combination of two or more machines
5. efficiency: a ratio of the work done by a machine compared with the work put into the machine

Sentences and illustrations:

1. A ramp is an example of an inclined plane.

2. An screw's  mechanical advantage is very high.

3. A wedge may have one or two slanted surfaces.

4. A pair of scissors is an example of a compound machine.

5. To calculate efficiency you need to make a radio.

Vocabulary # 5 (The Tools of Astronomers)

Definitions

1. universe: everything that exists
2. telescope: a device that collects light and make distant objects appear closer and larger
3. refraction: the bending of waves as they go from one substance to another
4. reflection: the bouncing of waves of a surface
5. wavelenght: the distance from one peak to the next in a wave
6. frequency: the number of waves that pass through a point in a second
7. electromagnetic spectrum: waves of light in order by wavelenght

Sentences and illustrations

1. The content of the universe include stars, galaxies, and planets.

2.  Astronomers observe the universe and try to explain it by using telescopes.

3. Refraction of light is the basis of eyeglasses and some telescopes.

4. Mirrors and some telescopes use reflection.

5. Wavelenght is measured in meters.

6.  Frequency is measured in cycles per second, or hertz.

7. Electromagnetic spectrum shows waves of light in order of their wavelenght.