Non-Contact Forces Review

Non-Contact Forces

Understanding Gravity, Magnetism, and Electric Forces

Review - Forces

• All objects are either in motion or still.

• To change an object's movement, apply a force.

• Forces can be strong or weak.

• As the mass of an object increases, you need to exert more force to change its movement.

Dropdown

An object that is moving is called ​

Select answer

,

but an object that is not moving is called ​

Select answer

.

Multiple Choice

To make a still object move, we need to apply ____.

• A force

• Sunscreen

• Early

Dropdown

A pull moves an object ​

Select answer

you,

but a push moves an object ​

Select answer

you.

Multiple Choice

Which force will move an object more?

• A strong force

• A weak force

Classifying Forces

• Scientists classify forces to make them easier to study.

• The classifications of forces are:

  • Contact Forces

  • Non-contact Forces

• Contact forces involve one object touching another object.

• Non-contact forces do not require the objects to touch. They work across a long distance.

Multiple Choice

Forces are classified as:

• Permanent

  Temporary

• Helpful

  Harmful

• Contact

  Non-Contact

• True

  False

Dropdown

​

Select answer

forces are exerted by objects that are touching,

while ​

Select answer

forces are exerted across a distance.

Distance and Force Strength

• Gravity, Magnetism, and Electric Forces are all examples of non-contact forces.

• All 3 forces are affected by distance.

• As distance increases, the strength of a non-contact force decreases.

• All 3 forces create a field.

• Only objects inside the field can be affected by the force.

Multiple Select

Choose the non-contact forces:

• Gravity

• Magnetism

• Electric Forces

• Pulling a rope

• Pushing a cart

Multiple Choice

Objects that are ___ attract more strongly.

• Close Together

• Far Apart

Multiple Choice

As two objects move farther apart, a force's strength will ___.

• Increase

• Decrease

• Stay the Same

Multiple Choice

Objects are only affected by non-contact forces if they are ___ the field.

• Inside

• Outside

• Under

Multiple Choice

To learn about Electric, Magnetic, or Gravitational Fields, ____.

• We can observe them directly.

• We have to make inferences.

Affected Objects

• Gravity acts on all objects all the time.

• Gravity pulls the strongest on objects with a high mass.

• Magnetism only acts on metal objects.

• Electric forces only act on charged objects.

• Objects become temporarily charged when they gain or lose electrons.

Multiple Choice

___ objects can be affected by gravity.

• Hot

• Cold

• All

Multiple Choice

Objects that are ___ attract more strongly.

• High Mass

• Low Mass

Multiple Choice

As two objects get heavier, Gravity's pull will ___.

• Increase

• Decrease

• Stay the Same

Multiple Choice

___ objects can be affected by magnets.

• Plastic

• Metal

• All

Multiple Choice

An object that exerts a magnetic force is called a ___.

• Magnet

• Magneto

• Mag-lev

• Magical

Multiple Choice

___ objects can be affected by electric forces.

• Charged

• Neutral

• All

Dropdown

Objects become ​

Select answer

charged when they gain or lose ​

Select answer

.

Attract or Repel?

• To attract is to pull objects towards each other.

• To repel is to push objects away from each other.

• Gravity can only attract objects.

• Magnetism and Electric Forces can attract or repel.

  • Opposites attract.

  • Matching repel.

Dropdown

​

Select answer

means to pull towards, while ​

Select answer

means to push apart.

Multiple Choice

Gravity can ____.

• Attract Only

• Repel Only

• Either attract or repel

Dropdown

Gravity's force is best described as a ​

Select answer

,

so it moves objects ​

Select answer

Earth's center.

Multiple Choice

Magnetism can ____.

• Attract Only

• Repel Only

• Either attract or repel

Multiple Choice

Electric forces can ____.

• Attract Only

• Repel Only

• Either attract or repel

Dropdown

​

Select answer

poles or charges attract,

but ​

Select answer

poles or charges repel.

Non-Contact Forces on Earth

• Earth has a huge mass, so it exerts a gravitational force that pulls all objects towards Earth's center. We measure this force using weight.

• Earth has a liquid metal Outer Core, so it exerts a magnetic force. When we use a compass, the magnetic force helps us navigate.

• In Earth's atmosphere, clouds rub together to transfer electrons, creating an electric force. The quick transfer of electrons around clouds creates a shock called Lightning.

Multiple Choice

On Earth, gravity pulls everything towards Earth's center because ___.

• Gravity can only ever pull down.

• The magnets from the core cause the gravity.

• Nothing on Earth has a bigger mass than Earth.

Multiple Choice

___ is a measure of mass X gravity.

• Volume

• Density

• Weight

Dropdown

On the moon, your ​

Select answer

will be the same,

but your​

Select answer

will be different than on Earth.

Multiple Choice

Earth's magnetic field is created by liquid metal in the ___.

• Crust

• Mantle

• Outer Core

• Inner Core

Multiple Choice

The magnetic ends of Earth are called ___.

• North Pole and South Pole

• East Pole and West Pole

• Attract Pole and Repel Pole

Multiple Choice

An Ancient Chinese invention that uses magnets to help humans navigate is ___.

• GPS

• A compass

• A map

Multiple Choice

Lightning is an example of the effects of ___.

• Electric Forces

• Magnetism

• Gravity

• Contact Forces

Multiple Select

Lightning can travel from ___.

(Pick all that apply!)

• Negative Clouds to Positive Clouds

• Positive Clouds to Negative Clouds

• Negative Clouds to Positive Ground

• Positive Clouds to Negative Ground

• Negative Ground to Positive Clouds