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  • Yeah.

  • Yep.

  • The barking dog experiment is one of our favorites.

  • We do it very frequently without a match.

  • It is a reaction of into, Oh, carbon die sulfide on.

  • When you ignite them, you get a blue flame on a great bush on dhe.

  • When we recorded it in slow motion, we realized we didn't understand the reaction as well as we thought we did.

  • So now we've decided to explore it a bit further, and the first thing we decided to do was instead of having the two vertically have it horizontally, where I have never seen the experiment done anyway except vertically.

  • So this may be a really first with the first thing That's interesting is that the gas lights long before the flame actually gets to the edge of the two.

  • The second thing waas that we noticed something that we've seen before.

  • The flame shoots along the tube and then suddenly stops and bounces and goes rather more slowly but oscillating no.

  • Up till now, we had assumed, and it may be the right explanation that the experiment produces a shock wave that hits the bottom of the test tube or the big tube and comes back again.

  • So the flame going this way meets the shockwave coming back, which stops it for a minute, like being thumped.

  • So we did another experiment with a tube with a rubber bang at the end.

  • Instead of being a closed big test of what we thought might happen, the bang might shoot away like a cannon.

  • As before, the flame started bouncing.

  • But if there was a shockwave, it wasn't enough to remove the bomb.

  • And if you think about it, it's really quite a heavy bag.

  • Neil, being a tough guy, had pushed it in quite hard.

  • So then we thought, Let's do the experiment with the tube open at the bottom.

  • As far as I know, nobody has ever tried such an experiment.

  • Least they may have tried it, but I've never seen it now.

  • We were really interested what sort of noise it would make on dhe.

  • It made a different noise, but the technician who pulled out the bun I was so startled he kicked over some glassware that was nearby.

  • So all you can hear is the sort of mixture of bush and breaking glass.

  • But the really interesting thing Waas if you watch it in high speed, the flame doesn't bounce anymore, so the explanation of the shock wave seems really quite sensible.

  • But what is also interesting is that the flame accelerates as it goes down the tube.

  • So what I think is happening is that the flame front, as it goes, compresses the gas just in front of it and raises the temperature so the gas is getting hotter and hotter.

  • So the reaction goes faster and faster.

  • And then you get quite a spectacular fireball coming out at the end, which is actually giving out blue light.

  • And the blue light is the mission of the excited electrons, partly from sulphur and partly from self for dioxide.

  • So is the really quite exciting experiment, but it hasn't answered all their questions, so it's really quite exciting.

  • It shows if you do more experiments, you learn more things.

  • But of course, it's given us lots more ideas.

  • So in a video or two's time, there'll be some more excitement from the barking dog.

  • Subscribe to our channel and you'll see some more barking dogs in interesting positions.

  • But actually, what this video footage is shown us is that it actually goes in stages.

  • It's sort of good.


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B1 flame tube experiment barking shockwave blue light

Horizontal Barking Dog - Periodic Table of Videos

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    林宜悉 posted on 2020/03/27
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