8th Grade physical Science Review

When automobiles are designed, engineers try to maximize their fuel efficiency. Even with modern technology, today's most efficient vehicles can only attain about 30% efficiency. That means of all the chemical energy of the fuel put into an automobile, only 30% of the fuel results in car motion. Which statement best explains why this happens?

• Most of the energy becomes chemical energy.

• Most of the energy is transformed into mass.

• Much of the energy is transformed into heat.

• Much of the energy is destroyed.

Tags

NGSS.HS-PS3-2

NGSS.HS-PS3-4

How is the balloon able to pick up the pieces of paper?

• Frictional force is overcoming gravitational force.

• Magnetic force is overcoming electrical force.

• Electrical force is overcoming gravitational force.

• Gravitational force is overcoming magnetic force.

Tags

NGSS.MS-PS2-4

Light waves can be reflected, refracted and absorbed. Which of the following is an example of light waves being absorbed?

• A ray of light travels from the Sun to Earth's atmosphere.

• A mirror changes the direction of a light ray.

• A magnifying lens increases the image size of a penny.

• A road's black pavement becomes hot in the sunlight.

Tags

NGSS.MS-PS4-2

The part of an atom that would be found outside the nucleus is the _______.

• electron

• positron

• proton

• neutron

Tags

NGSS.MS-PS1-1

Scientists use rovers to study Mars. The rovers are able to move and collect information from different locations on the planet. The following image shows a Mars rover. One Mars rover is named Curiosity. Curiosity had a mass of about 900 kg and a weight of about 8,800 newtons when it was on Earth. If Earth has a stronger gravitational pull than Mars, what is true about the mass and weight of Curiosity now that it is on Mars?

• Its mass is the same, but its weight is different than it was on Earth.

• Its mass and weight are both different than they were on Earth.

• Its weight is the same, but its mass is different than it was on Earth.

• Its mass and weight are both the same as they were on Earth.

Tags

NGSS.MS-ESS1-2

NGSS.MS-PS2-4

A student was studying chemical reactions. He followed these steps in an investigation:

Label one test tube X and another similar test tube Y.

Fill each test tube with 25 mL of the same acid solution.

Add 25 mL of the same salt solution to each test tube.

Carefully place test tube X in a beaker of water on a hot plate and increase the temperature.

Place test tube Y in a test tube holder on the table.

Record observations.

The student observed that a color change in test tube X occured faster than in test tube Y. Why did this happen?

• Raising the temperature increased the number of particles in the test tube.

• When the temperature was raised, the particles collided faster.

• Raising the temperature increased the air pressure around the test tube.

• When the temperature was raised, the particles became lighter.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

Using the propeller, a person can wind up the rubber band so that it is wound and tight. Upon release of the propeller, the rubber band quickly unwinds causing the propeller to spin and aid the toy plane in flight. Which statement best describes what energy transformation occurs upon release of the toy airplane's propeller?

• Potential energy is being transformed into kinetic energy.

• Kinetic energy is being transformed into potential energy.

• Thermal energy is being transformed into mechanical energy.

• Mechanical energy is being transformed into chemical energy.

Tags

NGSS.MS-PS3-5

The image is of a heating can. When the activating button is pushed, water mixes with calcium oxide. This produces calcium hydroxide in a chemical reaction which gives off heat. The heat warms up the food. What happens when this reaction occurs in the closed can?

• The mass of the can and its contents increases.

• The mass of only the food in the can decreases.

• The mass of the can and its contents remains the same.

• The mass of the can and its contents decreases.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A scientist wants to break down a newly discovered element. She wants to break it down to the smallest particle that retains the element's chemical properties. What particle would the scientist end with after this process?

• a proton

• a molecule

• an atom

• an electron

Tags

NGSS.MS-PS1-1

Two satellites are orbiting Earth. Both satellites have a mass of 1500 kg. Satellite X is traveling at a speed of 3,000 m/s and maintains an orbit 35,000 km from Earth. Satellite Y is traveling at a speed of 3,500 m/s and maintains an orbit of 25,000 km from Earth.

Which statement best describes the satellites?

• The two satellites are experiencing the same gravitational force.

• The two satellites are too far away from Earth to experience a gravitational force.

• Satellite X is experiencing a greater gravitational force than satellite Y.

• Satellite Y is experiencing a greater gravitational force than satellite X.

Tags

NGSS.MS-ESS1-2

NGSS.MS-PS2-4