8th Grade Science Final

What is Newton's Third Law of Motion?

For every action, there is an equal and opposite reaction.

What do unbalanced forces do?

They change motion and accelaration (speed or direction).

How do balanced forces affect motion?

There is no change in motion.

What happens when you push a wall?

The wall pushes back equally.

What influences the strength of electromagnetic forces?

Charge, current, magnet strength, and distance.

How do opposite charges interact?

They attract each other.

What do like charges do to each other?

They repel each other.

What forces act at a distance?

Gravity, electric forces, and magnetic forces.

What do gravitational fields affect?

They affect mass.

What do electric fields affect?

They affect charge.

What is potential energy?

Stored energy due to position.

What happens to gravitational potential energy when the height increases?

It increases.

Give an example of an object with high gravitational potential energy.

A book on a high shelf.

What happens when two objects interact?

Energy can transfer.

What occurs when a moving car hits a parked car?

Energy transfers from the moving car to the parked car.

Is energy lost during interactions?

No, energy is just transferred or transformed.

What happens to motion energy when an object falls?

It changes from potential to kinetic energy.

What is the cycle length of moon phases?

Approximately 29.5 days.

What causes day and night?

Earth's rotation.

What causes the seasons?

The tilt of Earth's axis and varying sunlight angles during its orbit.

In which galaxy is Earth located?

The Milky Way galaxy.

How was the solar system formed?

From a spinning disk of gas and dust pulled together by gravity.

What can cause changes in ecosystems?

Natural or human causes.

What is natural selection?

Traits that help survival/reproduction become more common due to environmental pressures.

How do adaptations occur?

Helpful traits become more common over generations due to DNA changes (mutations).

How can anatomical similarities indicate evolution?

They suggest a common ancestor.

What does the geologic time scale organize?

Earth’s history using rock layers and fossils.

What is the Law of Superposition?

Deeper rock layers are older than shallower ones.

What do simple waves consist of?

Repeating patterns: wavelength, frequency, amplitude.

What is wavelength?

The distance from peak to peak in a wave.

How is amplitude defined?

The height from rest to peak in a wave.

What do sound waves require to travel?

A medium (like air, water, or solids).

Can sound travel in a vacuum?

No, sound cannot travel in a vacuum.

What can light do when it interacts with materials?

It can be reflected, absorbed, or transmitted.

What is a characteristic of digital signals?

They are more reliable than analog signals.

What human activity contributes to climate change?

Releasing greenhouse gases like CO₂, mainly from burning fossil fuels.

What is the goal of science?

To understand natural events through evidence and testing.

What defines an adaptation?

A trait that helps an organism survive and reproduce.

What is the difference between natural and artificial selection?

Natural selection happens in nature based on survival, while artificial selection is human-driven.