Fall Final Review Physical Science

D=m/v

density equals mass divided by volume

V=d/t

velocity equals distance divided by time

A=(Vf - Vi)/t

acceleration equals change in velocity over time

F=ma

force equals mass times acceleration

P=mv

momentum equals mass times velocity

atom

the smallest unit of an element that retains its properties

scientific law

A statement that describes a natural event and is always true

model

a representation used to understand or explain an object idea, or process

hypothesis

a testable prediction based on observations before an experiment is conducted

independent variable

the variable that is changed or controlled in an experiment

dependent variable

the variable that is measured or observed

control variable

a variable kept constant to ensure a fair test when conducting an experiment

experiment

a procedure designed to test a hypothesis

pure substance

a matter with a fixed composition; either an element or a compound

element

a pure substance that cannot be broken down into any simpler substances

compound

a substance made of two or more elements chemically combined

homogeneous mixture

a mixture that is uniform throughout

matter

anything that has mass and takes up space

trace evidence

small pieces of evidence found at a crime scene

delta

a triangular ridge pattern found in fingerprints

class evidence

evidence that narrows down a suspect to a group

individual evidence

evidence that can be traced back to a single person or source

core

the center of a fingerprint patern

net force

the combination of all forces acting on an object

friction

a force that opposes motion

instantaneous speed

speed at a specific moment in time

intertia

the tendency of an object to resist a change in motion

pie graph

a graph that shows how a part relates to a whole

a title, labeled axes, and units

every graph must have____

observation

The step of the scientific method in which information is obtained through the senses

They help visualize, explain, or predict a phenomena

Why are scientific models important?

Repeated measurements that are close together

What makes a number precise?

meter

SI unit for length

second

SI unit for time

Kelvin

SI unit for temperature

water

What is an example of a pure substance?

saltwater

What is an example of a mixture?

smoothie

What is an example of a Homogeneous mixture?

salad

What is an example of a Heterogeneous mixture?

arches

fingerprint patterns in which ridge lines enter on one side and exit on the other side

Physical evidence

any evidence found at a crime scene

loops

Fingerprint patterns in which ridge lines enter on one side and exit on the same side

The shape and elongation of the drop

when analyzing blood drops, the angel of impact can be determined by ____

hair, fibers, glass

examples of trace evidence

latent print

an invisible impression left on a surface from the natural oils and sweat on a person's friction ridge skin (fingers, palms, feet), becoming visible only through development techniques like powder or chemical fuming, crucial for linking a suspect to a crime scene

plastic print

a visible, three-dimensional fingerprint impression left in a soft, moldable surface like wax, wet paint, soap, putty, or mud, capturing the ridges and valleys of the finger directly, and is easily preserved through casting

patent prints

fingerprint impressions left on surfaces when a substance like blood, paint, ink, or dirt transfers from the ridges of a finger, making the print clearly visible to the naked eye without special processing

when its speed or direction changes

When does an object accelerate?

Balanced forces

forces that even out, resulting in 0 net force or change to the objects motion

Unbalanced forces

forces that produce a net force other than 0, change the movement of the object

Newton

SI unit for force

always—between any two masses

When does gravitational force act?

Fluid friction

air resistance is a type of ____

net force __

the acceleration of an object is directly proportional to ___

at the same rate

if there is no air resistance, two objects with drastically different masses would fall ____

Law of Inertia

What is Newton’s First law also known as?

Objects resist changes in motion unless acted upon by an external force

What does Newton’s first law state?

inertia increases

When mass increases,____

attractive

gravity is a _____ force

F = ma; acceleration depends on force and mass

What is Newton’s second law?

the greater the acceleration

the less mass,____

for every action, there is an equal and opposite reaction

What is Newton’s third law?

gravity and forward velocity

what is projectile motion caused by?

momentum is conserved unless an outside force acts on the system

What is the law of conservation of momentum?