IBPhysicsDPHLRevision NotesInquiry ProcessInquiry 1: Exploring and Designing in PhysicsExploring in Physics

Exploring in Physics (DP IB Physics): Revision Note

Katie M

Written by: Katie M

Reviewed by: Caroline Carroll

Updated on

DP Physics: HLDP Physics: SL

Exploring in Physics

  • This is the creative start of the process where you act like a true scientist

  • It involves using your curiosity and existing physics knowledge to formulate a focused research question and a testable hypothesis

  • It requires independent thinking and consulting a variety of sources to understand the scientific context behind your idea and to make a clear, scientifically justified prediction

Developing your investigation

Demonstrate independent thinking, initiative, and insight

  • The best investigations often start with a simple question about a standard experiment

  • For example, "measuring the acceleration due to gravity, g."

  • You can show insight by framing it as a comparative investigation:

    • "To what extent does the mass of a pendulum bob affect its period of oscillation?"

  • This shows you are thinking about the assumptions within physical models

  • A common mistake is trying to investigate too many variables at once

  • A strong investigation explores the relationship between one independent variable and one dependent variable in depth

    • Avoid questions like "How do the length and mass of a pendulum affect its period?"

  • It is recommended that you choose just one factor and investigate it thoroughly

Consult a variety of sources

  • Before you can formulate a high-quality question, you need background information

    • This is a crucial research step

  • Good research helps you to:

    • understand the underlying physical principle

    • find established scientific values for comparison

    • identify a suitable method for collecting data

  • You can use various resources, including:

  • This research provides the scientific context for your investigation, showing that you understand the physics behind your question

Formulate research questions and hypotheses

  • A research question (RQ) must:

    • be focused

    • be specific

    • clearly state the link between the independent variable and the dependent variable

  • An RQ like "How does gravity affect objects?" is too general

  • A focused RQ usually has the form "What is the relationship between x and y?"

    • For example, "What is the relationship between the length of a simple pendulum and its period of oscillation?"

  • A hypothesis is not a guess

    • It is a clear, testable statement that predicts the outcome and includes a scientific justification

    • The best hypotheses follow an "If..., then..., because..." structure

State and explain predictions using scientific understanding

  • The "because" part of your hypothesis is where you explain your prediction

    • This explanation must be based on established physical principles, such as Newton's laws, conservation of energy, or relevant formulae

  • A hypothesis like "If the length increases, the period will increase" is just a prediction

  • To make it a valid scientific hypothesis, you must add the justification:

    • "...because the theoretical equation for the period of a simple pendulum, T space equals space 2 straight pi square root of L over g end root, shows that the period is directly proportional to the square root of the length."

Worked Example

Exploring an oscillation investigation

Broad idea:

  • I am interested in the factors that affect the time it takes for a pendulum to swing

Consulting sources and gaining insight:

  • My textbook shows that the formula for the period of a simple pendulum is

T space equals space 2 straight pi square root of L over g end root

  • This equation suggests that the period depends on the length L and the acceleration of free fall g

  • Crucially, the mass m of the pendulum bob does not appear in this equation, suggesting the period should be independent of the mass

Formulating the research question:

  • "What is the effect of the length of a simple pendulum on its period of oscillation?"

Formulating the hypothesis:

  • If the length of the pendulum is increased...

  • then the period of oscillation will also increase...

  • because the formula T space equals space 2 straight pi square root of L over g end root shows that the period T is directly proportional to the square root of the length square root of L

Worked Example

Exploring an electrical resistance investigation

Broad idea:

  • I want to investigate the factors that affect the electrical resistance of a wire

Consulting sources and gaining insight:

  • My textbook defines resistivity rho using the formula

rho space equals space fraction numerator R A over denominator L end fraction

  • where R is resistance, L is length, and A is the cross-sectional area

  • The formula shows a direct relationship between resistance and length. It also shows an inverse relationship between resistance and cross-sectional area.

  • Resistivity rho is a property of the material itself. I can find accepted values for the resistivity of different metals, like copper and constantan, from a reliable source, such as the CRC Handbook of Chemistry and Physics

Formulating the research question:

  • "What is the relationship between the length of a constantan wire of constant cross-sectional area and its electrical resistance?"

Formulating the hypothesis:

  • If the length of the constantan wire is increased...

  • then its resistance will increase proportionally...

  • because the formula R space equals space fraction numerator rho L over denominator A end fraction states that resistance is directly proportional to length, assuming a constant cross-sectional area and temperature

Worked Example

Exploring specific heat capacity

Broad idea:

  • I want to understand why different materials heat up at different rates

Consulting sources and gaining insight:

  • The syllabus defines specific heat capacity c as the energy required to raise the temperature of a unit mass by one degree, using the equation

Q space equals space m c increment T

  • Trustworthy databases, such as NIST, provide accepted values for the specific heat capacity of different materials

    • For example, the value for copper is much lower than for aluminium

  • This implies that less energy is needed to raise the temperature of copper compared to an equal mass of aluminium

Formulating the research question:

  • "How can the method of mixtures be used to experimentally determine the specific heat capacity of an unknown metal block?"

Formulating the hypothesis:

  • If a heated metal block is placed in a known mass of cool water...

  • then the specific heat capacity of the metal can be calculated...

  • because according to the principle of conservation of energy, the thermal energy lost by the metal block will be equal to the thermal energy gained by the water, allowing c for the metal to be determined from the equation:

m subscript metal c subscript metal increment T subscript metal space equals space m subscript water c subscript water increment T subscript water

Examiner Tips and Tricks

  • Struggling for an idea is normal.

    • Good starting points include:

      • A surprising or unexplained result from a class experiment.

      • Investigating a different aspect of a standard lab, such as the effect of temperature on a spring's stiffness.

      • Applying a physical concept to a real-world product, like investigating the bounce efficiency of different types of sports balls.

  • Check feasibility first.

    • Always consider if you have the right equipment, sensors, and time to actually carry out your investigation.

    • A great idea is not useful if it's not practical in a school lab.

  • Be prepared to refine your idea.

    • Your initial research might show that your first idea is not possible or practical.

      • Don't be afraid to change your RQ based on what you learn.

      • You may need to conduct additional research to help you refine the scope of your investigation.

      • This is part of the scientific process.

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    Author
    Reviewer
    Katie M

    Author: Katie M

    Expertise: Physics Content Creator

    Katie has always been passionate about the sciences, and completed a degree in Astrophysics at Sheffield University. She decided that she wanted to inspire other young people, so moved to Bristol to complete a PGCE in Secondary Science. She particularly loves creating fun and absorbing materials to help students achieve their exam potential.

    Caroline Carroll

    Reviewer: Caroline Carroll

    Expertise: Physics & Chemistry Subject Lead

    Caroline graduated from the University of Nottingham with a degree in Chemistry and Molecular Physics. She spent several years working as an Industrial Chemist in the automotive industry before retraining to teach. Caroline has over 12 years of experience teaching GCSE and A-level chemistry and physics. She is passionate about creating high-quality resources to help students achieve their full potential.