Scientific Method and Variables
In an experiment to test how fertilizer affects plant growth, what is the independent variable?
The amount of fertilizer.
What is a force?
A push or pull that acts on an object.
What is Newton’s First Law also called?
The Law of Inertia.
What force pulls objects toward Earth?
Gravity
Why do seatbelts protect passengers in a crash?
Inertia keeps passengers moving unless a force stops them.
A student tests if listening to music while studying improves test scores. What is the dependent variable?
test scores
What unit is used to measure force?
Newton (N).
State Newton’s Second Law.
Acceleration of an object is affect by force and mass
why are astronauts floating inside the space station
due to microgravity
If a swimmer pushes water backward, why do they move forward?
Newton’s Third Law (action-reaction).
A scientist studies how different water temperatures affect fish activity. What is the independent variable?
The water temperature
What is the force that opposes motion between two surfaces?
Friction.
Give an example of Newton’s Third Law.
A rocket launching (gases goe down, rocket moves up).
What type of friction slows down objects moving through air?
Air resistance
Why does a skateboarder eventually stop even if they don’t push the ground?
Friction and air resistance slow them down.
Why do scientists repeat experiments?
To ensure reliability and accuracy of results.
What happens when forces acting on an object are balanced?
The object stays still or moves at a constant speed
What will happen to an object in motion if no external force acts on it?
It will keep moving in a straight line at the same speed.
What happens to gravity as the distance between two objects increases?
Gravity decreases.
Why do cyclists wear streamline shaped helmets and tight clothing?
To reduce air resistance (friction with air) and move faster.
A scientist tests if fertilizer increases plant height. What is the controlled variable?
Type of plant, amount of water, amount of soil
What tool is used to measure force?
Spring scale.
What law explains why it’s harder to push a full shopping cart than an empty one?
Newton’s Second Law.
Why is it harder to walk on ice than on a rough surface like concrete?
Because ice has less friction
Why do car tires have grooves instead of being completely smooth?
To increase friction and provide better grip on the road, especially in wet conditions.