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Lesson 4: Fields

# Fields

Review your understanding of fields and the forces that create them in this free article aligned to NGSS standards.

## Key points:

• A field represents empty space around an object where a non-contact force, like gravity or an electric force, could exist.
• The idea of fields was created to help explain how objects can exert forces on each other, even when they’re not touching each other.
• Fields exist around objects with certain properties.
• Gravitational fields exist around objects with mass.
• Electric fields exist around objects with charge.
• Magnetic fields exist around magnetic objects.
• Each location in a field has a magnitude and direction. We can represent this by drawing field lines at different points around an object. These field lines can then be used to help explain the forces that an object would experience in that location.

## Want to join the conversation?

• Wouldn't dark energy be classified in physics? It is a type of energy after all and the opposite of gravity, right? Actually, what specifically is dark energy? Give me a vote if you think this is interesting. And give it to :P. He also gets the credit for answering this question. Thank you :P!
P.S - Could someone please give me one more vote? That is all I need. Thank you very much.
• that's scary
• What makes the earth orbit around the sun
• The gravity from the sun.
• In the video, they said that the closer an object gets to another object's field of gravity, then the object will feel a stronger pull of gravity. Is that what happens inside black holes? Is that why even light cannot escape? I think it might be because of how much mass the black hole has right?
• Yes, the black hole is very, very dense. This means its mass is very large. Because of this, it sucks in everything near it. Even light.
• how can you tell where a gravatational force is?
• Anywhere something has mass.
• can you guys also upvote me
• If an object has enough mass could it collapse on itself? And could that object have a moon that would exert enough gravitational force on the object for it to prevent the object from collapsing on itself?
• Yes, when and object collapses in on itself, whoch is usually a star, it either goes supernova, and spreads the matter everywhere, sometimes making a nebula, collapses, becoming a black hole, or becomes a neutron star but I forgot how that one worked. And also I don't think a moon or planet or even other star could prevent a dying star from collapsing or exploding, as it would need to take away it's matter from it. A black hole could.
• What makes the earth orbit around the sun?
• Gravity