VCE Physics – Special Relativity Theo Hughes (Education Manager – School of Physics & Astronomy)

What am I presenting? Special Relativity (SR) in the new Study Design VCE Physics Study Design 2016-2021 p39 Einstein’s theory of special relativity Unit 3, AoS 3 Note: bit about SR and energy in next section of Study Design

Why am I presenting on this? Because I’ve been asked… … and I find these ideas particularly interesting! Also, for teachers, one or more of: Less familiar (option in previous Study Design, that few did) Particularly conceptually tricky Persistent misconceptions (textbooks, exams, internet, academics)

What will I cover? Limited time – other resources Mainly time dilation

What you already know? Good pedagogy?

window of space station VCE Exam Question – Past Detailed Study A rocket passes a space station at a speed of 0.80 c parallel to the side of the space station. There is a circular window on the space station, as shown in Figure 1. Question Which of the following figures best shows how the window would look to the person passing in the rocket? direction of rocket window of space station   Figure 1 A person inside the passing rocket observes the window.

window of space station Simple Correction to Exam Question A rocket passes a space station at a speed of 0.80 c parallel to the side of the space station. There is a circular window on the space station, as shown in Figure 1. Question Which of the following figures best shows how the window would be measured by the passing rocket? direction of rocket window of space station Figure 1 A person inside the passing rocket observes the window.

Length Contraction and Time Dilation refer to what we measure. Not in Study Design Length Contraction and Time Dilation refer to what we measure. E.g. video next slide “look” / “see” at “high speeds” – is NOT in Study Design.

Through Einstein’s Eyes Website: Through Einstein’s Eyes videos, software, info and references to relevant papers Professor Craig Savage (ANU)

Other resources Wikipedia Articles: Length contraction Terrell Rotation (with link to Relativity Visualised) Relativistic Doppler Effect Open Relativity – open-source code to simulate visual effects near light speed A Slower Speed of Light : a simple game using this code

VCE Exam? If examiners continue to pose such questions, just tell your students to answer with the standard length contraction and time dilation answers. i.e. assume “look” / “see” = “measure” … and then make a lot of noise about incorrect questions!

Time Dilation Wibbly wobbly, timey wimey

Queue other set of slides… This slide is intentionally left blank 

Summary Key Skill One-clock vs two clock Key Points: Identifying which measurement of time interval is shorter / longer One-clock vs two clock One-clock (proper time) smaller, two clocks larger Multiply or divide by gamma as appropriate Key Points: Time dilation equation ≠ what time looks like What time looks like is NOT covered by Study Design