⚖️ BALANCE
What does it mean for an object to be balanced?
The forces acting on the object are balanced enough for the object to remain stable.
What is motion?
Motion is a change in an object's position.
What is one important job of an airplane's wings?
The wings interact with the air and help create forces that affect the airplane's motion, including helping produce lift.
What can a force do to an object's motion?
A force can change an object's motion by causing it to start, stop, speed up, slow down, or change direction.
A soccer ball is sitting still. You kick it, and it starts moving. What scientific idea just happened?
A force changed the ball’s motion.
A sculpture is not perfectly symmetrical, but it remains standing. Does that automatically mean it is unbalanced?
No. An object can be asymmetrical and still be balanced if it remains stable.
A student pushes a stationary box and it begins moving. What caused the change in motion?
The student's push was a force that changed the box's motion.
Why does air matter when an airplane is flying?
Air interacts with the airplane's wings, creating forces that affect the airplane's motion.
Why did we use a control airplane during our investigation?
The control airplane gave us something to compare with the airplane in which we changed a variable.
You are riding in a car when the driver suddenly stops. Your body wants to keep moving forward. What concept explains this?
Inertia.
A sculpture begins to tip after its weight is changed. What might this tell you about the forces acting on it?
Changing the weight distribution affected the balance of the sculpture, causing it to become unstable and tip.
What is inertia?
Inertia is the tendency of an object to keep doing what it is already doing unless a force changes its motion.
What is lift?
Lift is a force that helps an airplane move upward and stay in the air.
A scholar adds weight to a paper airplane and the airplane flies differently. What should the scholar do before claiming that the added weight caused the difference?
The scholar should compare the changed airplane with the control and make sure the test was conducted fairly, with only the intended variable changed.
You build a sculpture that looks a little crooked, but it stays standing. Is that possible?
Yes! An object can be asymmetrical and still be balanced.
Why might changing the position of an object's weight affect whether it remains balanced?
Moving the weight changes how the weight is distributed, which can change the balance of the object.
A moving ball eventually stops. Explain why this does not mean inertia “disappeared.”
Inertia did not disappear. A force acted on the ball and changed its motion, causing it to stop.
An airplane changes direction while flying. What does this tell us about forces and motion?
The airplane's motion changed, so a force affected its motion and caused it to change direction.
A scholar says, “My airplane flew better because I changed the force.” What evidence would make this explanation stronger?
Specific observations or measurements showing that changing the force caused a difference in the airplane's motion.
You make two paper airplanes. One has heavier wings, and one has lighter wings. You launch them with the same force. What could you investigate?
How the change in weight affects their motion/flight.
Two sculptures have the same amount of weight. One remains standing, while the other tips over. What could explain the difference?
The weight may be distributed differently in the two sculptures. The position of the weight can affect whether an object remains balanced.
A toy car is moving forward. A student pushes it from the side, and the car changes direction. What happened to the car's motion, and what caused the change?
The car's motion changed because a force acted on it and changed its direction.
Two paper airplanes are launched with similar force. One stays in the air longer than the other. What is one variable the scientists could investigate to determine why?
They could investigate a variable such as the shape of the wings or the weight of the airplane, while keeping other conditions similar.
A scholar changes both the weight of an airplane and the force used to launch it. The airplane flies farther. Can the scholar confidently say that the added weight caused the airplane to fly farther? Why or why not?
No. The scholar changed two variables, so they cannot tell which change caused the difference. They should change only one variable at a time.
You change the weight and the launch force of your paper airplane. It flies farther. Can you say which change caused it? Why?
No. Because two variables were changed, you cannot tell which one caused the difference. You should change only one variable at a time.