IB Physics SL S2.1 Exploring and designing Questions

SLSL HLHL

Practise IB Physics SL S2.1 by turning a physics question into a testable plan with variables, controls, apparatus and safety.

7 questions in this syllabus scope, with question parts counted together.

Exam points & syllabus

Exam points

Identify and hold fixed the physical properties that affect the result, naming the actual object, such as the nail, wood, bob or ball.
Explain a control by linking it to the dependent variable and isolating the independent variable’s effect; do not rely on “fair test” alone.
Use multiple values of the independent variable to test its relationship with the measured outcome or to plot the proposed graph.
Improve a limited range by extending the named variable’s range, as in selecting stars with a wider range of surface temperatures.
Give a measurable control, such as release angle or cable length; “same cable” or “same rod” without a stated feature can be insufficient.
Read control choices in their experimental context: a number of oscillations is accepted in the rod task but rejected in the stated pendulum task.

Covered syllabus points

S2.1.1—Exploring S2.1.2—Designing investigations S2.1.3—Controlling variables

Exam points

Identify physical factors that set a fitted constant, such as the load, paper thickness or number of wraps in the cylinder-collapse investigation.
Choose a control that belongs to the stated setup; for the pendulum task, initial amplitude or a specified bob property is accepted.
Name the object when specifying a control: for rebound tests, control the ball’s drop height, speed or a stated ball property.
Vary the independent variable to test the relationship or construct a graph; repeated readings at only one value do not provide that variation.
When the assessed weakness is the data range, propose a wider range of the named independent variable, such as stellar surface temperature.
Explain a control by linking it to the dependent variable and the need to isolate the effect of the variable being changed.
Specify a measurable feature to keep constant, such as release angle or cable length; “use the same apparatus” alone may be insufficient.

[Maximum number: 1]

A student studies the relationship between the centripetal force applied to an object undergoing circular motion and its period T.
The object (mass m ) is attached by a light inextensible string, through a tube, to a weight W which hangs vertically. The string is free to move through the tube. A student swings the mass in a horizontal, circular path, adjusting the period T of the motion until the radius r is constant. The radius of the circle and the mass of the object are measured and remain constant for the entire experiment.

The student collects the measurements of T five times, for weight W. The weight is then doubled ( 2 W ) and the data collection repeated. Then it is repeated with 3 W and 4 W. The results are expected to support the relationship

W=\frac{4 \pi^{2} m r}{T^{2}}

State why the experiment is repeated with different values of W.

In reality, there is friction in the system, so in this case W is less than the total centripetal force in the system. A suitable graph is plotted to determine the value of m r experimentally. The value of m r was also calculated directly from the measured values of m and r.

In order to draw a graph« of W versus $\frac{1}{\mathrm{~T}^{2}}$ »

OR

to confirm proportionality between « W and $T^{-2}$ »

OR

to confirm relationship between « W and T »

OR

because W is the independent variable in the experiment

OWTTE.

[Maximum number: 1]

A group of students uses pressurized air to move a piston that forces a nail into a block of wood. A gauge is used to measure the pressure P of compressed air above atmospheric pressure. The nail enters the wood perpendicular to its surface.

The students use a ruler to measure the length of the nail which remains above the surface of the wood as shown. The depth of the nail inside the wood is d. All necessary length measurements are recorded using a ruler with uncertainty $\pm 1 \mathrm{~mm}$ .

The students systematically increase the pressure and calculate d.

State one variable that needs to be controlled when collecting the data.

More syllabus points

S2.1.1—ExploringNo questions yet

No public sample questions are available for this syllabus point yet.

Question 1

Question 1

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