Dissecting the haul

[Graeme H]

Yep that is confusing Graeme. I had imagined the transverse wave to be a wave travelling through the line.

It is Paul. I've said that numerous times. Maybe it's getting lost when I write other things, so just again:

The loop is travelling through the line.

Cheers,
Graeme

[Graeme H]

An example:
Let's say the loop forms at t = 0 seconds

At t = 0.1 s, the loop has travelled 0.5 metres along the line from the rod tip. (0.1 seconds has passed since we formed the loop)

At t = 0.2 s, the loop has travelled 1 m along the line from the rod tip.

At t = 0.3 s, the loop has travelled 1.5 m along the line from the rod tip.

At t = 0.4 s, the loop has travelled 2 m along the line from the rod tip.

At t = 0.5 s, the loop has travelled 2.5 m along the line from the rod tip.

As time passes, the loop moves along the line away from the rod tip

The loop is travelling through the line

[Graeme H]

[Paul Arden]

Ok but I was reading this, Graeme:

The fly leg is part of the wave. One leg of the wave.

I didn’t see how the wave can be travelling through the line if it is the line.

Cheers, Paul

[Graeme H]

The loop is not the line. The line is the line.

The loop is a wave. When I say that, I quite literally mean you can swap the words in a sentence.

Loop = Wave.

The [OBJECT] travels from the rod tip to the fly through the line.

You can select the following to substitute in for [OBJECT]:

• Tail
• Mend
• Dolphin nose
• Loop

You're probably thinking "But the loop travels away from me!"

So let's substitute words here. The sentence is now "But the wave travels away from me!"

Okay, well if you put a mend in the line, the wave travels away from you. If you put a tail in the line, the wave travels away from you. If you put a dolphin nose in the line, the wave travels away from you.

If you put a wave in the line, it travels away from you. Choose any name you like, it still travels away from you through the line.

The line doesn't travel away from you. It's still attached to your rod.

Cheers,
Graeme

[Paul Arden]

I’m sure you can call the loop a wave, Graeme. Just like you can call a whip a wave.

What I think is confusing is the use of the term “transverse wave”. Because that would indicate that the wave runs perpendicular to the tip path, and to me at least would be the cause of the development of the loop. Whereas we seem to agree that the cause of loop motion is the momentum of the fly leg.

A transverse wave is “motion in which all points on a wave oscillate along paths at right angles to the direction of the wave's advance.” However with the loop of the floor we have seen that this only happens when the fly leg is given momentum in this direction. That indicates to me that it is the fly leg that is responsible for the travelling loop (wave, whatever), and not any transverse nature of a wave travelling up through the line.

I think that sums it up. Because if it’s the fly leg momentum that causes this to work then transverse wave equations can’t be used to describe loop motion.

But I’m no physicist. What I am is late. Gotta run!

Cheers, Paul

[Graeme H]

A whip is a whip, not a wave. We can make a wave travel along a whip though.

I'm late too.

[Bernd Ziesche]

The loop is travelling through the line.

Hi Graeme,
"THE" loop is making me think.

I prefer to say:
We accelerate our line and then have it unroll in a permanently changing form of a loop.

I have zero use to intruduce a second term "wave" here.
And then differentiating different types of waves. Seems endless to me.
Regards
Bernd

[Bernd Ziesche]

I’m sure you can call the loop a wave, Graeme. Just like you can call a whip a wave.

Hi Paul,
Yes, or you can call your fly rod to be a lever, a spring, a spring and a lever, a car brick model, a harmonic oscillator, a flexible lever, a dildo or whatever you like. But your students will still buy it as what it is...a fly rod.
Cheers
Bernd

[Graeme H]

I have zero use to intruduce a second term "wave" here.
And then differentiating different types of waves. Seems endless to me.
Regards
Bernd

I call the loop "the loop" too.

Like you say, calling everything "THE wave" without differentiating isn't helpful unless there is a reason to use a unifying pronoun (and there is a reason here). Just telling the student to watch the wave isn't going to help because they need to know which one I want them to watch.

But waves are waves, and grouping like entities enables consistency and efficiency in a lesson or discussion. Traffic on a freeway consists of motor vehicles. We don't need to say the BMWs, Mercedes, Skodas and Fords move with certain speeds in certain lanes. We can group them and call them cars, since they all behave the same way on the road. Singling out individual cars with a brand name has purpose but saying the Ford is not a car is incorrect.

Treating everything except the biggest bend in the line as one type of wave and the main one we see as something new to science is a problem for me and my students (and not one student has ever struggled with the wave concept as far as I know). I can and do use one wave as the analogy for the behaviour of the others. Some are easier to see than others, so they are good to explain the concept and then extend to the others in the family of waves in the line. They all behave the same way, travelling at the same speed through the line - which is useful in all sorts of ways.

Cheers,
Graeme