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 Mass in grams (g)

Gold 96.5

Lead 110.0

Iron 158.0

Aluminum 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

0

5

10

15

20

A B C

A

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.

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.)

Liquid Mass(grams)

Volume(cm3)

CornSyrup

10.8 10.0

SaladOil

23.0 25.0

Vinegar

30.3 30.0

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?

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 C. nucleus◦ B. neutron D. proton

◦ Answer = A. electron

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 C. reflection◦ B. diffraction D. refraction

Answer = D. refraction

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 H. speed of the storm◦ G. speed of sound 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.

Car Mass(kg)

A 1250

B 2000

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?

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 30-newton (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 H. the handle◦ G. the string I. the rotation direction

Answer = G. the string◦ (The string keeps the ball from flying away just

as does the gravity of the star.)