Investigating Force and Splash Height

A student wants to investigate how the force with which a ball is thrown affects how high of a splash it makes in a pool. Which table BEST represents how the investigation should be set up?

• A) Independent variable: Type of ball; Dependent variable: Weight of the ball; Controlled variables: Force the ball is thrown with, Height the ball is thrown from

• B) Independent variable: Height of the splash; Dependent variable: Force the ball is thrown with; Controlled variables: Type of ball, Height the ball is thrown from

• C) Independent variable: Weight of the ball; Dependent variable: Type of ball; Controlled variables: Height of the splash, Force the ball is thrown with, Height the ball is thrown from

• D) Independent variable: Force the ball is thrown with; Dependent variable: Height of the splash; Controlled variables: Weight of the ball, Type of ball, Height the ball is thrown from

Answer explanation

Choice D correctly identifies the independent variable as the force with which the ball is thrown, and the dependent variable as the height of the splash. It also includes relevant controlled variables, ensuring a valid investigation.

Tags

NGSS.MS-PS2-2

Students conduct experiments to investigate friction. Which experiment will best test the effect of friction on objects?

• Drop two balls from the same height at the same time

• Roll two marbles on the carpet from the same starting point at the same time and with the same amount of force

• Roll three marbles across three different surfaces from the same starting point at the same time and with the same amount of force

• Release two balls from the top of a ramp at the same time

Answer explanation

Rolling three marbles across different surfaces allows for direct comparison of friction effects, as each surface will provide varying resistance. This setup isolates the variable of surface type while controlling other factors.

Tags

NGSS.MS-PS2-2

Students investigate force. The masses they use begin at rest on the ramp. The setup the students use is shown. Which change will reduce the amount of force needed to move the masses?

• Decrease the height of the ramp

• Increase the height of the ramp

• Add an additional mass

• Pull the spring scale with two hands

Answer explanation

Decreasing the height of the ramp reduces the gravitational potential energy acting on the mass, which in turn decreases the force needed to move it. A lower ramp angle means less force is required to overcome gravity.

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

A student conducts the investigation shown in the diagram. In this experiment a paper cup hangs from a string tied to a single uncooked spaghetti noodle. The student measures and records the mass of a penny. The student then adds pennies to the paper cup one at a time. Which question is the student most likely trying to answer with this investigation?

• How many spaghetti noodles will it take to hold up the mass of a penny?

• How much force will it take to break the spaghetti noodle?

• How long should the string that holds the paper cup be in order to support the greatest mass of pennies?

• How does the distance between the two chairs affect the amount of force it takes for the spaghetti noodle to break?

Answer explanation

The student is adding pennies to measure the force exerted on the spaghetti noodle. This directly relates to how much force it will take to break the noodle, making that the most likely question being investigated.

Tags

NGSS.MS-PS2-2

A student builds the circuit shown. The student closes Switch 1 and Switch 3. Which lightbulb will glow? Select ONE correct answer.

• L1

• L2

• L3

• L4

Answer explanation

Closing Switch 1 and Switch 3 completes the circuit for L1, allowing current to flow through it. Therefore, L1 will glow, while L2, L3, and L4 will not receive power.

Students create the circuit shown. What do the lightbulb and the bell do when the switch is left open?

• The lightbulb glows, and the bell rings.

• The lightbulb glows, and the bell does not ring.

• The lightbulb does not glow, and the bell rings.

• The lightbulb does not glow, and the bell does not ring.

Answer explanation

When the switch is open, the circuit is incomplete. Therefore, the lightbulb does not receive power and does not glow, while the bell, which may require a complete circuit to ring, also does not ring.

Tags

NGSS.MS-ETS1-1

Students made the circuit shown. Cutting the wire at which numbered position would allow two of the lightbulbs to remain lit?

• Position 1

• Position 2

• Position 3

• Position 4

Answer explanation

Cutting the wire at Position 2 creates a break that allows current to flow to two lightbulbs while isolating the others. This configuration keeps two bulbs lit, making Position 2 the correct choice.

A group of students builds the electric circuit shown. Which switches must be closed for Bulb 1 to remain dark but Bulb 2 to produce light?

• Switch 1 only must be closed.

• Switches 1 and 3 must be closed.

• Switches 2 and 3 must be closed.

• Switches 1, 2, and 3 must be closed.

Answer explanation

For Bulb 1 to remain dark, Switch 1 must be open. Closing Switches 2 and 3 allows current to flow through Bulb 2, lighting it up. Thus, the correct choice is that Switches 2 and 3 must be closed.

Which circuit shown will produce light when the switch is closed?

• A

• B

• C

• D

Answer explanation

Circuit B completes the circuit when the switch is closed, allowing current to flow and light to be produced. The other circuits either have a break or do not connect the light properly.

Tags

NGSS.MS-ETS1-2

A group of students is building the circuit represented in the diagram. What object can be used at Position X for the buzzer to sound when Switch K is closed?

• A power source

• Another bulb

• An insulated wire

• Another switch

Answer explanation

A power source is necessary to provide the electrical energy needed for the buzzer to sound when Switch K is closed. Without a power source, the circuit cannot complete, and the buzzer will not activate.