Greg wrote the following paper about the science involved in designing roller-coaster
rides. Read Greg’s paper and look for any revisions he should make. When you finish
reading, answer the questions that follow.
It Takes Science
(1) Imagine being on a roller-coaster track. (2) You feel the cars slowly
climbing to the top of a large hill. (3) Suddenly the roller coaster plunges steeply.
(4) It bends and turns as it swiftly follows the curves of the track. (5) Happy
screams fill the air as the brief but thrilling ride comes to an end. (6) Riding on a
roller coaster may last only a few minutes. (7) Planning a new roller-coaster ride,
however, takes several years. (8) Science and a lot of other things are needed to
design a fun and working roller coaster.
(9) Ride design begins with a computer program. (10) The program
calculates the forces that will affect the roller-coaster cars as they move along the
track. (11) Designers must understand the limits these forces create when building
and improving roller coasters. (12) Designers use their knowledge of friction,
gravity, and the laws of motion to make the ride act in a way they plan. (13) This is
the reason there are often large hills on roller coasters. (14) Designers take
advantage of gravity to generate speed on their ride as cars lower these slopes.
(15) Gravity causes the cars to increase their speed as they go down the hill.
(16) Speed alone is not enough for a fantastic roller coaster, though.
(17) Designers often add loops and twists to rides. (18) However, roller coasters
must be safe as well as exciting. (19) My favorite roller coaster in Texas has a drop
that is over 200 feet long. (20) Friction and gravity are key factors in determining
how far designers can push the limits of a ride. (21) Will the cars have enough
speed to complete the loop? (22) Will the cars move too fast to stay on the track
during an abrupt turn? (23) These are questions designers must use science to
answer.
(24) Another aspect designers need to consider is which material to use to
build the roller coaster. (25) Steel roller coasters can be built with steeper hills than
wooden roller coasters can handle. (26) Steel roller coasters are generally faster
9 of 24 Set 1
Grade 8, Revising
than wooden ones. (27) Steel also allows wheels to ride more smoothly over a track
than wood does. (28) Additionally, steel is stronger than wood. (29) Steel can
withstand the forces of a car pressing against the track in tight turns and loops
better than wood can. (30) There seem to be a lot of advantages with steel.
(31) Even the smallest detail must be considered when building new roller
coasters. (32) For example, too much paint on a track can cause friction. (33) This
is a problem because it affects the roller coaster’s speed. (34) Jeff Pike, president of
Skyline Attractions, states, "The one thing that will slow down a steel coaster is a
buildup on the track rails." (35) A good track will have worn paint. (36) This makes
the coaster move more quickly.
(37) As science and technology advance, designers are constantly searching
for ways to build faster and more complex roller coasters. (38) Designers are
excited and hopeful about the possibilities of roller-coaster designs. (39) "Everybody
is going higher and taller," says Kent Seko, a roller-coaster designer with Arrow
Dynamics. (40) Designers aim to set new records with each new roller coaster they
design because that is their objective.
(41) The sky is the limit when it comes to roller-coaster design. (42) Yet, one
thing remains constant. (43) A well-designed roller coaster relies on knowledge of
the laws of force and motion to ensure the ride is an amazing experience for
everyone on board.
10 of 24 Set 1
Grade 8, Revising
7 Greg would like to provide a more effective controlling idea for his paper. Which sentence
should replace sentence 8 to effectively state the controlling idea of this paper?
A Quite a bit of knowledge is needed to figure out how the best roller coasters work.
B Hard work, science, and having lots of other skills are needed to design popular roller
coasters.
C Roller coasters have to be fun, so the scientists who design and build them must know
something about amusement parks.
D Designing an exciting roller-coaster ride involves imagination and creativity, but it also
requires using science.