Unit 5 · Weakening Arguments

Solid Glass Debate — Weaken the Argument

Lesson 9 of 9

Premium

About this lesson

The argument says medieval glass is thicker at the bottom because glass flows very slowly over centuries. One option introduces ancient glass from Egypt and Greece — which is far older — that shows NO thickening at the bottom. If glass truly flows, older glass should show the effect more, not less.

Chapters

0:00Introduction
0:22Question
1:33Strategy
2:26Step 1: Test the theory's own prediction
3:26Step 2: Test each option — D fails the prediction
4:41Correct answer

Question

‘Solid’ glass can actually be better described as a slow-moving liquid. The particles in glass can move, just like in a regular liquid, because they are not fixed in an orderly structure. In glass, this movement is so slow that it cannot be detected during a person’s lifetime or even over the course of several generations. Medieval window glass which has survived to the present day is often found to be thicker at the bottom than at the top. This clearly shows that glass flows.

Which one of these statements, if true, most weakens the above argument?

Free account · Selective

Take your Selective prep further

  • Sample questions & worked solutions across core Selective topics
  • Digital exam simulator with interactive practice sets
  • Personalised progress tracking across all your devices
Create free account

Already have an account? Log in here

No payment required. Compare Selective plans

0 of 9 lessons completed

0%

Give Your Child the Best Chance at Selective Entry

Join NSW families preparing their children for the Selective Schools Placement Test with the most realistic online Selective practice tests available. First tests free—no credit card required.

Claim Your Free Selective Practice Tests