8TH GRADE SCIENCEHERMON MIDDLE SCHOOL

Force

Mass

● The amount of “stuff” in an object● Closely related to weight / how “heavy” something is

● Measured in grams (g)● Kilograms (kg), milligrams (mg), etc.

Inertia

● An object’s resistance to a change in motion● Based on an object’s mass

● The more mass an object has (more massive), the more inertia it has

● This is what keeps the dishes on the table when the table cloth is yanked out from underneath

● Newton’s First Law: Objects at rest will stay at rest, and objects in motion will stay in motion, unless they are acted upon by an outside (unbalanced) force

Force

● Defined as a PUSH or a PULL● Force (F) = Mass (m) * Acceleration (a)● Balanced forces will not change an object’s

motion● Unbalanced forces will change an object’s

motion● Units for force are NEWTONS (N)

● 1 N = 1 (kg * m) ÷ s²● Newton’s Second Law states that F=ma

Nerdy Humor

Friction

● A force that occurs when surfaces touch (are in contact)

● Always OPPOSES (works against) motion● If an object is moving, friction slows it down● If an object is at rest, friction makes it more difficult

to move

Static Friction

● Occurs between surfaces that are not moving (relative to each other)

● Friction that holds an object “still”

Sliding Friction

Rolling Friction

Fluid Friction

● Something moving across a “greased” surface● Air hockey puck● Ice skates● Skis

● Challenge: name 2 examples of fluid friction that would be acting on the above ship

Gravity

● A property of all matter● Similar to magnetism… BUT:

● VERY, VERY weak● Only attracts, does not repel

● Related to an object’s MASS● The more massive an object is, the more

gravitational pull it has

● Why can we feel Earth’s gravity, but nothing else’s?