Appositive: Robert H. Goddard, a pioneer in American rocketry, was first to use gasoline and liquid oxygen instead of gunpowder as fuel. (5)

Noun: Robert H. Goddard, a pioneer in American rocketry, was first to use gasoline and liquid oxygen instead of gunpowder as fuel. (3)

Appositive: In 1957 a Soviet rocket launched Earth’s first artificial satellite, Sputnik I. (2)

Noun: In 1957 a Soviet rocket launched Earth’s first artificial satellite, Sputnik I. (2)

Appositive: Satellite pictures, exact maps of Earth, can pinpoint the spread of plant diseases. (4)

Noun: Satellite pictures, exact maps of Earth, can pinpoint the spread of plant diseases. (2)

Appositive: Meteorologists, scientists who study weather, can predict dangerous storms using radio waves converted to pictures. (4)

Noun: Meteorologists, scientists who study weather, can predict dangerous storms using radio waves converted to pictures. (1)

Appositive: Communication satellites, receivers and transmitters of radio waves, make communication possible from continent to continent. (6)

Noun: Communication satellites, receivers and transmitters of radio waves, make communication possible from continent to continent. (2)

Appositive: Geostationary satellites, satellites that orbit at the same speed as Earth’s rotation, are used for telecommunications, weather forecasting, and even spying. (10)

Noun: Geostationary satellites, satellites that orbit at the same speed as Earth’s rotation, are used for telecommunications, weather forecasting, and even spying. (2)

Appositive: Space probes, satellites that travel close to other worlds, were first launched in 1959 when the first probe raced past the moon. (7)

Noun: Space probes, satellites that travel close to other worlds, were first launched in 1959 when the first probe raced past the moon. (2)

Appositive: In 1974 the Mariner 10 came within 203 miles of Mercury, the planet closest to the sun. (6)

Noun: In 1974 the Mariner 10 came within 203 miles of Mercury, the planet closest to the sun. (1)

Appositive: Probes of Mars, the planet most like Earth, help us understand our own planet. (5)

Noun: Probes of Mars, the planet most like Earth, help us understand our own planet. (1)

Appositive: Voyager 1 and Voyager 2 were probes that photographed the planet Jupiter. (1)

Noun: Voyager 1 and Voyager 2 were probes that photographed the planet Jupiter. (1)

Appositive: Few countries have launch sites, points from which a rocket can carry a satellite into space. (11)

Noun: Few countries have launch sites, points from which a rocket can carry a satellite into space. (2)

Appositive: My aunt Helene bought a farm outside Toledo. (1)

Noun: My aunt Helene bought a farm outside Toledo. (1)

Appositive: The comics, Seth and Josh, kept us in stitches for hours. (3)

Noun: The comics, Seth and Josh, kept us in stitches for hours. (1)

Appositive: She moved to Albany, the capital of New York. (5)

Noun: She moved to Albany, the capital of New York. (1)

Appositive: During first and second periods I have my best courses, science and math. (3)

Noun: During first and second periods I have my best courses, science and math. (1)

Appositive: Kimane, the soccer captain, got an award. (3)

Noun: Kimane, the soccer captain, got an award. (1)

Appositive: I watched a documentary about Hank Aaron, the baseball great who broke Babe Ruth’s home run record. (10)

Noun: I watched a documentary about Hank Aaron, the baseball great who broke Babe Ruth’s home run record. (2)

Appositive: Walden is my favorite book by the naturalist Henry David Thoreau. (3)

Noun: Walden is my favorite book by the naturalist Henry David Thoreau. (1)

Appositive: My fingers, cold sticks of ice, were frostbitten from being out in the cold too long. (4)

Noun: My fingers, cold sticks of ice, were frostbitten from being out in the cold too long. (1)

Appositive: I write for our student newspaper Hall Pass. (2)

Noun: I write for our student newspaper Hall Pass. (2)

Appositive: Was that your famous relative, the mountain climber? (3)

Noun: Was that your famous relative, the mountain climber? (1)

Appositive: My oldest brother, Tim, is on leave from the air force. (1)

Noun: My oldest brother, Tim, is on leave from the air force. (1)

Appositive: My cat Huckleberry lived for almost twenty years. (1)

Noun: My cat Huckleberry lived for almost twenty years. (1)

Appositive: Let’s see the theater’s new production, Arsenic and Old Lace. (4)

Noun: Let’s see the theater’s new production, Arsenic and Old Lace. (1)

Appositive: Rami, my best friend, is moving out of town. (3)

Noun: Rami, my best friend, is moving out of town. (1)

Appositive: The dancers, members of Ms. Contreras’s class, leaped and twirled through the audience. (5)

Noun: The dancers, members of Ms. Contreras’s class, leaped and twirled through the audience. (1)