[LINK] ChatGPT

[Bernard Robertson-Dunn]

I just had a conversation with ChatGPT

Me: what is a Bravais pendulum

ChatGPT:  A Bravais pendulum is a simple pendulum with a single point of 
suspension and a spherical bob, named after French physicist Auguste 
Bravais. It is used to determine the local value of g, the acceleration 
due to gravity, by measuring the time period of oscillation.

Me: no it isn't

ChatGPT:  I apologize, it seems my previous answer was incorrect. Can 
you please provide more information or correct my understanding of a 
Bravais pendulum?

Me:  a Bravais pendulum is a pendulum that swings in an ellipse not a 
straight line

ChatGPT  :Thank you for correcting me. Yes, you are correct. A Bravais 
pendulum is a type of pendulum that swings in an elliptical path, not a 
straight line. This is due to the combination of the pendulum's weight 
and the effects of Earth's rotation. The elliptical path of the pendulum 
is used to study the laws of planetary motion.

Me:  why does it gain time when it rotates one way and loses when it 
rotates the other way

ChatGPT:  The behavior of a Bravais pendulum can be understood by 
considering the effects of Earth's rotation on the pendulum's motion. As 
the pendulum swings, it experiences a Coriolis force that acts 
perpendicular to both its velocity and the axis of rotation of the 
Earth. This force causes the pendulum's motion to deviate from a 
straight path and follow an elliptical path instead.

ChatGPT:   When the pendulum swings in one direction, the Coriolis force 
causes it to move in a direction that is ahead of its original path, 
effectively "gaining time." When it swings in the other direction, the 
Coriolis force causes it to move in a direction that is behind its 
original path, effectively "losing time." This results in a variation of 
the period of oscillation with the orientation of the pendulum, and is 
an example of how the Earth's rotation affects the motion of objects.

Comments:

Its first response was a direct statement with no indication of 
uncertainty . But wrong.

When I challenged it, it told me I was correct, repeated what I had said 
and added additional information

When I asked a further question - which is actually what makes Bravais 
pendulum so interesting - it gave me even more additional information, 
but that information is wrong.

"This force causes the pendulum's motion to deviate from a straight path 
and follow an elliptical path instead" By definition a Bravais pendulum 
starts with an elliptical path and the force only modifies the period.

Why didn't it start with all the information it eventually gave me?

And how would I know if it ever gets it right? It happens that I know 
about a Bravais pendulum, but others might not be in the same position.

Apart from responding in smooth English, it is about as trustworthy as 
Wikipedia or Google. They both provide a starting point but there is a 
need to check. At least Google gives you links to many alternative 
routes to a variety of answers and Wikipedia has references you can 
follow up.

Unfortunately, you seem to have to know something about the question and 
its possible/probable answer to work out if it is telling you useful 
information.

To me it looks rather like GPS navigation systems. Don't put blind trust 
in either.

-- 

Regards
brd

Bernard Robertson-Dunn
Canberra Australia
email: brd at iimetro.com.au