Transcript document

Big Ideas: Physical & Chemical Sciences
Earth & Space Changes

Danielle has four different metal cubes. The
mass in grams (g) and the volume in cubic
centimeters (cm3) of each cube are shown
below.
Metal Type
Gold
Lead
Iron
Aluminum
Mass in grams
(g)
96.5
110.0
158.0
108.0


Density definition = ratio of mass to volume
Density = Mass/Volume
◦
◦
◦
◦
Gold 96.5g / 5.0cm3 = 19.3g/cm3
Lead 110.0g / 10.0cm3 = 11g/cm3
Iron 158.0g / 20.0cm3 = 7.9g/cm3
Aluminum 108.0g / 40.0cm3 = 2.7g/cm3
◦ Answer = A. gold
20


The graph below shows the relationship
of the mass in grams (g) of three liquids
at the same temperature and with the
same volume.
What conclusion about density can be
drawn from this graph?
◦ Density is not always related to mass and
volume.
◦ Substances of different volumes have the
same density.
◦ It is less difficult to measure the density of
liquids than of solids.
◦ Equal volumes of different substances may
have different densities.
15
10
A
5
0
A
B
C

Answer = Equal volumes of different
substances may have different densities.

A test tube is placed into containers of water with
different temperatures. The water plug in the glass
tubing will move up as the temperature increases.
Which statement explains why
the water plug in the glass
tubing moves upward as
temperature in the test tube
increases?
F. The water plug becomes more dense.
G. The air pressure decreases in the test
tube.
H. The capillary action moves the water plug.
I. The air molecules in the test tube increase in energy.

Answer = The air molecules in the test tube
increase in energy.
◦ (Heat transfers from the water through the glass of
the tube. The increase in the thermal energy
provides more kinetic energy to the gas molecules
and they move faster and farther, needing more
space in which to move. Thus, the plug is pushed
upwards.)


Mr. Molina’s class
studied the mass and
volume of three
liquids.
What is the
difference in density
between the least
and the greatest
density of the
liquids?
Liquid
Mass
Volume
(grams) (cm3)
Corn
Syrup
10.8
10.0
Salad
Oil
23.0
25.0
Vinegar 30.3
30.0

Density = mass/volume
◦ Corn syrup
 10.8g / 10.0cm3 = 1.08g/cm3
◦ Salad oil
 23.0g / 25.0cm3 = 0.92g/cm3
◦ Vinegar
 30.3g / 30.0cm3 = 1.01g/cm3
◦ Answer = corn syrup (1.08g/cm3) – salad oil
(0.92g/cm3) = 16g/cm3

Atoms are made of subatomic particles.
Which of the following subatomic particles
has the least mass?
◦ A. electron
◦ B. neutron
◦ Answer = A. electron
C. nucleus
D. proton

The movement between points A to D is
generally horizontal motion. Between points B
and C the vertical motion accelerates. What is
the force behind this acceleration?

Answer = gravity
◦ (Newton’s Law – An object moving in a straight line
will continue to move in a straight line at a constant
speed unless acted upon by an outside force.)

If the flight of the ball was such that the hole
and flag were missed, the ball would roll past
the hole until it eventually stopped. What force
acts on the ball to change its motion and cause
it to stop?

Answer = friction
◦ (Friction always opposes motion – again, Newton’s
Law - An object moving in a straight line will
continue to move in a straight line at a constant
speed unless acted upon by an outside force.)


There is only one fish in the fishbowl below. When
Joseph looks down at the fish, the image he
observes is closer to the surface than the actual
location of the fish.
Which wave characteristic does Joseph’s
observation demonstrate?
◦ A. amplitude
◦ B. diffraction
C. reflection
D. refraction

Answer = D. refraction
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
The picture below shows a bird sitting on a
post near an ocean pier. Water waves are
moving past the bird. Every 20 seconds (s),
10 waves pass by the bird. Each wave has a
wavelength of 3.0 meters (m).
What is the frequency, in hertz (Hz), of the
water waves as they pass the bird?

Answer = number of events (waves) / time (s)
= 10 waves/ 20 seconds= 0.5Hz

Mason and his friends were playing baseball
outside his house when they saw lightning and
heard thunder rumbling in the distance. They
wanted to know how far away the storm was, so
they went inside, and as soon as they saw the next
lightning flash, they started counting seconds until
they heard the thunder. For every three seconds
they counted, they know the storm was about one
kilometer away. Which of the following properties
did Mason and his friends us to determine the
distance of the storm?
◦ F. speed of light
◦ G. speed of sound
H. speed of the storm
I. speed of the lightning

Answer = speed of sound
◦ Distance = speed x time
◦ Distance = 340.29 m/s x time


Gail’s cross-country coach advised her to eat
well-balanced meals in order to have plenty
of energy for their upcoming track meet. To
which transformation of energy is Gail’s
coach referring?
Answer = C. Chemical energy to mechanical
energy


Quinn has a container for making frozen juice
bars. He pours juice into the container and
then puts the container into the freezer for
12 hours. What happens to the juice
molecules in the container during these 12
hours?
Answer = They lose kinetic energy.


A calorimeter is a device used to measure the
energy content of food. In a calorimeter, a
measured amount of food is burned, heating
a known mass of water. The temperature
change of the water is measured with a
thermometer. Which type of energy present in
food can be measured by the calorimeter?
Answer = chemical


When electric power is carried over long distances through
power lines, the electrical energy decreases as the distance
increases. This energy decrease occurs because the current
encounters resistance in the wires.
What happens to the electrical energy as it travels through the
power lines?
◦ The energy converts into thermal energy and is released into the
atmosphere.
◦ The energy converts into electromagnetic energy and is released as
microwaves.
◦ The energy is transferred to the current’s electrons as the power lines are
grounded.
◦ The energy is transferred to the air as light energy as it travels along the
power lines.

Answer = The energy converts to thermal
energy and is released into the atmosphere.


An oscilloscope is an instrument that can be
used to display the properties of waves.
Melanie studies four pictures of waves from
an oscilloscope.
Which picture shows waves with the shortest
wavelength?

Answer = H. III



Thomas and Kelsey are using a jump rope
to model a typical wave. The wave they
produce has a frequency of 4.2 hertz (Hz),
an amplitude of 2.5 meters (m), and a
wavelength of 5 m. What is the velocity, in
meters per second (m/s), of this wave?
Answer (reference sheet:
wavelength = velocity / frequency)
◦ velocity = wavelength x frequency
◦ Velocity = 5 x 4.2 = 21m/s


Leah is using a 3.4-meter (m) ladder to
paint the exterior of her house. Leah has a
mass of 50 kilograms (kg). The acceleration
due to gravity is equal to 9.8 meters per
second squared (m/s2). What force, in
newtons (N), odes Leah exert on the ladder
when she is standing on it?
Answer
◦ Force = mass x acceleration
◦ Force = 50kg x 9.8m/s2 = 490N


Chris and Luis each have a body mass of 60
kilograms (kg). They are standing next to
each other on a stage. Each boy exerts a
force of 588 newtons (N) on the stage. What
is the total force, in newtons (N), that the
stage exerts on both boys?
Answer = 588N + 588N = 1176N
◦ (Newton’s Law – Every action force has an equal
and opposite reaction force. The force of the two
boys push down on the stage and the stage
pushes back.)


Sam drops a rubber ball from the top of a staircase to his
friend, as shown in the picture below. The speed of the ball
increases as it gets farther away from Sam’s hand.
What is the best explanation for the increase in the speed of
the ball?
◦
◦
◦
◦
Electric forces are acting on the ball.
Air resistance is accelerating the ball.
Magnetic forces are pushing the ball.
Gravitational force is pulling on the ball.

Answer = I. Gravitational force is pulling on
the ball.


Two cars accelerate at a
rate of 3 meters per
second squared (m/s2).
The mass of each car, in
kilograms (kg), is shown
in the chart below.
How many more newtons
(N) of force (kg x m/s2)
are needed to accelerate
the car with the larger
mass?
Car
A
Mass
(kg)
1250
B
2000

Answer
◦ First calculate the force required for both cars
 F = m x a = 1250kg x 3 m/s2 = 3750N
 F = m x a = 2000kg x 3 m/s2 = 6000N
◦ Then, to find the extra force required to accelerate
the car with more mass, subtract the above two
answers.
 6000N – 3750N = 2250N


Lisa is seated at the front of a train. The train is
traveling northbound at a steady speed of 40.2
kilometers/hour )km/hr). While the train is in
motion, Lisa gets up from her seat and walks
toward the back of the train at a steady rate of 2.4
km/hr.
What is Lisa’s actual rate of speed, relative to the
ground, in km/hr in a northbound direction at the
time that she is walking toward the back of the
train?

Answer = 40.2km/hr – 2.4km.hr =
37.8km/hr
◦ (The forces acting on Lisa are in opposite
directions. Her actual motion across the ground
is a result of the net force.)


Melissa wants to help her friend lift a box using a
board and a rock.
Where should Melissa position the fulcrum in order
to minimize the amount of force needed to lift the
box?
◦
◦
◦
◦
A. point A
B. point B
C. point C
D. point D

Answer = D. Point D


Amanda placed a small television on a metal
rolling cart. On her way to the library, her
friend
Carlos stepped in front of the cart. Although
Amanda stopped suddenly, the television
stayed in place on the cart. What kept the
television on the cart when she stopped
suddenly?
Answer = A. friction



Paula is using an inclined plane to move a 30newton (N) box
What is the ideal mechanical advantage (IMA) of the
inclined plane when it is used to move the box?
Answer = (IMA = distance / height) = 6m / 2m = 3


Using a string, a ball, and a hollow tube for a
handle, LaTanya makes the model shown below.
Holding the handle’s center, she swings the ball in
a circle to show how a planet orbits a star. She
knows that the orbit of a planet depends upon the
gravitational pull of the star.
Which model component illustrates the effect of
gravity?
◦ F. the ball
◦ G. the string
H. the handle
I. the rotation direction

Answer = G. the string
◦ (The string keeps the ball from flying away just as
does the gravity of the star.)