science 8 sem 1

bru

Science

The study of the behavior and structure of the physical and natural world through observation and experimentation.

Scientific Method/Scientific Inquiry

A way to ask and answer questions by making observations and doing experiments.

Variable

A factor that can change in an experiment.

Independent Variable

The factor that is changed by the experimenter.

Dependent Variable

The factor that is affected by and measured due to the independent variable.

Constant

Factors in an experiment that do not change.

Control

The standard, untreated group used for comparison.

Observation

The process of using one’s senses to gather information.

Hypothesis

An educated guess based on knowledge and observations.

International System of Units (Metric System)

A global measurement system built on seven base units.

Qualitative Data

Data that describes characteristics without using numbers.

Quantitative Data

Data that includes numerical measurements.

Pie (Circle) Graph

A circular graph divided into portions, often used to show percentages.

Line Graph

A graph used to show changes over time.

Bar Graph

A graph using rectangular bars to compare quantities.

Scientific Method Step 1

State the problem.

Scientific Method Step 2

Form a hypothesis.

Scientific Method Step 3

Conduct an experiment.

Scientific Method Step 4

Analyze the data.

Scientific Method Step 5

Draw conclusions.

Controlled, Valid Experiment (Super Bubbles)

No, because results were inconsistent and measurements were unprofessional.

Control Group (Super Bubbles)

The regular bubble soap group.

Constants (Super Bubbles)

The amount of water used.

Dependent Variable (Super Bubbles)

Bubble size (diameter).

Independent Variable (Super Bubbles)

Type of bubble soap used.

Type of Data Collected (Super Bubbles)

Quantitative data.

Scientific Inquiry in Super Bubbles

They tested a claim by conducting an experiment.

SI Base Unit for Time

Seconds.

SI Base Unit for Length

Meters.

SI Base Unit for Force

Newtons.

SI Base Unit for Mass

Kilograms.

50 kg in grams

50,000 g.

4630 mg in grams

4.63 g.

0.42 km in meters

420 m.

Scientific Theory

Explains why something happens.

Scientific Law

Describes what happens.

Repetition

When the original scientist repeats their experiment.

Replication

When a different scientist repeats an experiment.

Best Graph for Plant Growth Data

Line graph.

X-axis Label for Plant Graph

Weeks.

Y-axis Label for Plant Graph

Plant height.

Independent Variable (Plant Experiment)

Type of fertilizer.

Dependent Variable (Plant Experiment)

Plant growth.

Conclusion from Plant Data

Fertilizer B caused the most growth.

Reference Point

A fixed point used to determine an object’s position.

Position

The place where an object is located.

Acceleration

The rate at which velocity changes.

Average Speed

Total distance divided by total time.

Displacement

The change in position from a reference point.

Distance

The total path length traveled.

Instantaneous Speed

The speed at a specific moment in time.

Speed

Distance traveled per unit of time.

Velocity

Speed in a given direction.

Motion

A change in position relative to a reference point.

Distance vs. Time Graph Slope

Represents speed.

Distance vs. Time X-axis

Time.

Distance vs. Time Y-axis

Distance.

Increasing Speed on Distance-Time Graph

Curved line upward.

Decreasing Speed on Distance-Time Graph

Curve leveling off.

Constant Speed on Distance-Time Graph

Straight diagonal line.

Stopped on Distance-Time Graph

Horizontal line.

Speed vs. Time Graph Slope

Represents acceleration.

Speeding Up on Speed-Time Graph

Diagonal line upward.

Slowing Down on Speed-Time Graph

Diagonal line downward.

Constant Speed on Speed-Time Graph

Horizontal line.

Cyclist Travel Time (800 km)

6.3 days.

Satellite Acceleration

−625 m/s².

Average Speed (Round Trip Cyclist)

22.5 km/h.

Displacement (Round Trip Cyclist)

0 km.

Clara’s Speed

66.7 m/s.

Mason’s Race Time

16.7 minutes.

Elvis’s Bike Distance

30 m.

Speed Racer’s Speed After 10 s

500 m/s.

Ball Drop Time

2.5 s.

Roller Coaster Acceleration

37.5 m/s².

Karen’s Velocity

5 m/s north.

Race Winner

Albert.

Runner Who Rested

Charlie.

Rest Time

5 seconds.

Bob’s Race Time

14 seconds.

Albert’s Average Speed

8.3 m/s.

Stopped Line on Speed-Time Graph

Line U.

Highest Speed on Speed-Time Graph

20 m/s.

Lines Showing Acceleration

R and V.

Line Showing Decrease in Speed

T.

Acceleration of Line R

5 m/s².

Force

A push or pull.

Contact Force

A force requiring physical contact.

Noncontact Force

A force that acts without physical contact.

Balanced Forces

Equal forces that cause no change in motion.

Unbalanced Forces

Unequal forces that cause motion.

Gravity

The force that attracts objects toward Earth’s center.

Mass

The amount of matter in an object.

Weight

How heavy an object is due to gravity.

Friction

A force that resists motion between surfaces.

Net Force

The total force acting on an object.

Inertia

An object’s resistance to changes in motion.

Newton’s First Law

Objects stay at rest or in motion unless acted on by a force.

Newton’s Second Law

Force causes acceleration in the direction of the force.

Newton’s Third Law

Every action has an equal and opposite reaction.