I watched the whole video and I think it is good, but that may have little bearing on a viewing by a 10-11 year. Additionally, there is no standard 10-11 year old, so one aspect is whether you simply want to “reach” as many as possible (lowest common denominator) or concentrate on feeding those that want more of that material. I think that it is a legitimate differentiation and it is difficult to do both.
We all show some interest in seeing something that we can’t “normally” see because it is essentially mind-expanding. The IR cam does that beautifully. It was mentioned that you might not hold the rubber band in your hand because of the visual heat transfer. You could work that to your advantage by using tongs first and then your hands. After which, the demonstration can proceed as you have done.
The magnets would benefit by a similar visualization (I am sure you know how better than me,
https://www.coolmagnetman.com/magvisual.htm).
So, when you get to gravity, the effect on quartz oscillators requires a transition, and it is difficult, but the demonstration works well I think. The challenge is in not going too far explaining an oscillator and time keeping and rubidium. Maybe the way you are doing it is fine – I am thinking that you will get declining attention/understanding at that point, but that may not be a bad thing – feeding those that want more of that material …..i.e., sometimes it is difficult to “see” forces but we can tell they are there….
A small point is consistency of language. At ~ 5:20 you say “the energy is removed” and I wonder about how language-careful you have to be and which words they hang on.
I have given many presentations to many adults and when you have a fixed amount of time and detailed information, I always had a sinking feeling about lying, not to be deceptive, but because the alternative is to take up all the time with prerequisite detailed explanations. My point is to somehow, streamline and simplify oscillators and frequency. Sitting here, drinking coffee, I considered a metronome as an introduction – but I don’t know if that would work.
Lest anyone thinks I am being too critical, let me state outright that if you did not change anything, the presentation has value and is better than many I had as a 10-11 year old (and yes, I do remember).