100 Days of 8th Grade Science

What is the force that pulls objects toward the center of the Earth?

• Friction

• Gravity

• Magnetism

• Inertia

Answer explanation

The force that pulls objects toward the center of the Earth is gravity. It is a fundamental force that attracts masses towards each other, and in this case, it pulls everything towards the Earth's center.

Tags

NGSS.MS-PS2-4

What is the term for a push or pull on an object?

• Force

• Energy

• Mass

• Speed

Answer explanation

The term for a push or pull on an object is 'Force'. It is a fundamental concept in physics that describes the interaction that causes an object to change its motion.

Tags

NGSS.MS-PS2-1

Which of the following is an example of a physical change?

• Burning wood

• Rusting iron

• Melting ice

• Baking a cake

Answer explanation

Melting ice is a physical change because it involves a change in state from solid to liquid without altering the chemical composition. In contrast, burning wood, rusting iron, and baking a cake involve chemical changes.

What is the term for the force of attraction between all matter?

• Inertia

• Friction

• Net force

• Gravity

Answer explanation

The force of attraction between all matter is called gravity. It pulls objects toward each other, and is responsible for keeping planets in orbit and objects on the ground, unlike inertia, friction, or net force.

Tags

NGSS.MS-PS2-4

Which has more mass, Earth or the Moon?

• Earth

• Moon

• The same

Answer explanation

Earth has significantly more mass than the Moon. Specifically, Earth's mass is about 81 times greater than that of the Moon, making Earth the correct choice.

Tags

NGSS.MS-ESS1-3

What is the next logical step engineers would take to design and produce a smaller laptop computer after identifying the need?

• Build a new type of laptop battery

• Research current laptop technology

• Build a prototype computer

Answer explanation

The next logical step is to research current laptop technology. This helps engineers understand existing designs, components, and limitations, which is essential before developing a smaller laptop.

Tags

NGSS.MS-ETS1-1

What is a simple model that lets you test out your design called?

• Protoplasm

• An archetype

• A prototype

• A proton

Answer explanation

A prototype is a simple model used to test and validate design concepts. It allows designers to explore ideas and gather feedback before finalizing the product, making it the correct choice in this context.

Tags

NGSS.MS-ETS1-4

What is the most likely cause if a new type of refrigerator designed to use less electricity is not working correctly after being sold?

• The proper cost analysis was not performed.

• The designers did not test other types of machines.

• They did not rigorously test and modify the prototype.

Answer explanation

The most likely cause of the refrigerator's issues is that they did not rigorously test and modify the prototype. Proper testing is essential to identify and fix potential problems before the product is sold.

Tags

NGSS.MS-ETS1-4

What step might be included when optimizing a design solution?

• Drawing models

• Testing a prototype

• Analyzing data

• All of the above

Answer explanation

Optimizing a design solution involves multiple steps, including drawing models to visualize ideas, testing prototypes to evaluate functionality, and analyzing data to inform decisions. Therefore, 'All of the above' is the correct choice.

Tags

NGSS.MS-ETS1-3

NGSS.MS-ETS1-4

What is the next step after completing research in the engineering design process?

• Define the problem

• Develop a possible solution

• Build a prototype

• Test your solution

Answer explanation

After completing research, the next step in the engineering design process is to develop a possible solution. This involves brainstorming and creating potential designs based on the findings from the research.

Tags

NGSS.MS-ETS1-4