User suggestion: electrocute the dog

[oliver-phet]

p.s. while playing, I tried to electrocute the dog and the “hand” taken from the grab bag. Even at 100000v dc and max ac - the current in dog was 0 and negligible in the “hand” ... not sure why these examples were given… maybe a “wet dog” would catch on fire – kinda like the pencil burst into flame - big time!!

[ariel-phet]

I am fairly sure that it was a conscious decision to no longer allow animal cruelty

[oliver-phet]

It might be best to remove those options from the grab bag in the HTML5 version?

[arouinfar]

@oliver-phet we plan to keep the dog in HTML5, but we will not allow users to electrocute it. If you've already responded to the user can you go ahead and close this issue?

[oliver-phet]

Another user emailed:

I've used your electricity simulator with my classes for many years. This year when we were working with the conductors and insulators we noticed that the hand will show that's it's conductive if you used the high voltage battery with the highest voltage. However, when we tried the same solution, the dog does not show that's its conductive. Can you explain why this is the case? Or how can I show students that dogs are conductive just like humans?

[oliver-phet]

Another email:

We love your simulations! Thank you for the opportunity to use them. I just have a suggestion/request on the circuit construction kit dc. Please get rid of the dog as an option. My students are working hard to catch the dog on fire and will argue that it is virtual. I think it just sends the wrong message.

[arouinfar]

I've also heard some similar feedback from teachers at ISTE and AAPT. Teachers are concerned that the resistance of the dog is unrealistically high.

I think we're going to need to decide if the whimsy of a cruelty-free dog outweighs the incorrect physics. Perhaps not?

I think we need to either get rid of the dog or give it a more realistic resistance. If we go with the latter, the maximum current one could send through the dog would be about ~4 amps. Definitely enough to electrocute the poor doggo 😞but not enough to short/set the dog on fire (which was possible in one of the older Java versions).

@ariel-phet can you review and advise?

[ariel-phet]

@arouinfar I would be fine with either getting rid of the dog or giving it a more realistic resistance. I think the main point is the dog cannot be allowed to catch on fire.

My guess is that for nostalgia reasons @kathy-phet will want to keep the dog.

Currently, with the value of resistance for the hand, the maximum amperage is about 0.4 A. I imagine we could it make the dog similar (maybe just twice the resistance of the hand). I believe right now the hand is about an order of magnitude too high (100,000 Ohms is quoted as the dry "high" resistance of the human body) in terms of being realistic.

[ariel-phet]

@arouinfar feel free to make the call, or we could ask @kathy-phet to make the call

[kathy-phet]

To some degree, we could make voltage safety could be a learning goal. Happy to chat through options.

Sent from my iPhone

On Jul 24, 2019, at 6:59 PM, Ariel Paul notifications@github.com<mailto:notifications@github.com> wrote:

@arouinfarhttps://github.com/arouinfar feel free to make the call, or we could ask @kathy-phethttps://github.com/kathy-phet to make the call

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[samreid]

It would be time consuming to implement, but we could reimplement the dog as a fuse in series with a resistor. She could retract her paw and open the circuit when the current limit is exceeded.

Another possibility would be to only allow the dog to appear in scenes where the maximum voltage (of all batteries in series) is a safe level.

[samreid]

It seems this would be good to discuss at an upcoming CCK design meeting, particularly if we want to work on this before AC publication. Also, even if we decide there will be no grab bag items in the AC sim, it may be beneficial to republish DC at the same time as AC to keep them in sync, if time allows.

[samreid]

Notes from today's meeting. Cut the front paw junction when current level exceeded. Show dog turns head to side, and a short bark sound.

[arouinfar]

1/9/20 design meeting notes

• Update dog resistance to match the hand (100000 ohms)
• Get additional artwork of the dog, head turned to face user with mouth slightly open.
• Treat dog like a fuse. When max current reached (0.1 amps), swap out artwork and play "yip" sound.
• Cut junction at the dog's paw. The mechanics would be identical to using the cut button, severing the connection of all components at the junction.

UPDATE BY @samreid: match => max

[arouinfar]

Assigning @samreid to work on the fuse-like mechanics, but leaving self assigned to work with the graphic artist.

[samreid]

After the above commits, when the current through the dog exceeds the threshold, it barks and splits the junction at the front paws. I used placeholders for the bark image and audio, and it should be ready to test functionality. Self-unassigning until we have improved bark image and audio or feedback on this draft.

[arouinfar]

@samreid the behavior is looking good! I see the "Bark" text, but I don't actually hear a sound. Not sure if you have a stand-in audio file, or you just have the architecture ready to go once there is a sound to incorporate.

[samreid]

Thanks for letting me know! I had failed to push the *.mp3 file. After pushing, I confirmed I can hear the audio on phettest.

[arouinfar]

Thanks @samreid. Looks like the mechanics are all in place now.

[oliver-phet]

Another user email received:

Hallo,

this visualisation is very DANGEROUS!!!

After this visualisation children think that current or voltage ist not dangerous. The same is happen with the dog.

PLEASE change this fakt immediately.

With 120V the human is DEATH.

[samreid]

On hold until artwork/assets are complete.

[samreid]

Increasing priority since this was requested for upcoming release.

[samreid]

We reviewed the case in https://github.com/phetsims/circuit-construction-kit-common/issues/512#issuecomment-642244320 and agreed as long as the current is only through the hand and the current is low, it would not be a health risk.

We reviewed the behavior in master and agreed it is OK. We feel there are pedagogical advantages of showing a disembodied hand, so students can see that hands are not perfect insulators. We don't want to have the hand recoil.

[samreid]

We also agreed we would like to have a "dog looks at the camera/head tilt" graphic for the upcoming publication. See https://github.com/phetsims/tasks/issues/1021.

@arouinfar will reach out to C.M.

[samreid]

@arouinfar can you please comment on the expected timeline for this issue?

[arouinfar]

The artist who created the dog currently in CCK is on hiatus from PhET until February. I sent an email to @samreid @kathy-phet @ariel-phet to discuss next steps.

[arouinfar]

Possible options

1. Work with a different artist, which would probably require new altogether new dog artwork.
2. Wait on adding new artwork until the original artist is available in February. Proceed with publication without the secondary dog artwork, but plan to republish CCK: DC after CCK: AC is published.
3. Forget secondary dog artwork, and find some other way to visually indicate that the dog barked or the current was too high. Some rough sketches:

[samreid]

The cartoonish "!!!" speech bubble looks great to me for next release.

[kathy-phet]

I like the cartoon "!!!" as well.

[ariel-phet]

Looks good

[arouinfar]

I cleaned up the speech bubble a bit. Here are the assets @samreid: dog_bark.zip

If you prefer to draw it in code, the speech bubble is fontawesome f075. The exclamation points are Times New Roman. The right/left exclamation points are 20% smaller and rotated 20 degrees away from the central !. You could also go with the fontawesome exclamation point f12a.

[samreid]

We already had the "comment" path data. I added the exclamation point path, and wired it up in the commit. It looks like this:

@arouinfar can you please review in master?

[arouinfar]

@samreid the speech bubble is looking great, but its duration feels a bit too short. If you aren't looking at the dog when the current threshold is exceeded, it's easy to miss.

Can we try something like 0.5 s? I realize this means the speech bubble will be visible for a bit longer than the audio duration, but I think that's ok.

[samreid]

I increased the time to 0.5 seconds and positioned the bark relative to the dog so it would look OK at different rotations. Ready for review.

[samreid]

Also, I kept the bark always "upside up" like so, but we could rotate it with the dog if we prefer:

[arouinfar]

@samreid the speech bubble duration looks great! In general, I like the "upside up" approach, but there are a few rotations where the dog ends up occluded so it might not be the best solution.

[samreid]

After the commit, the speech bubble rotates with the dog. I also noticed that electrons or other circuit elements can overlap the speech bubble, but I don't think that would be trivial to change the z-ordering. @arouinfar ready for review.

[arouinfar]

Looking good in master @samreid. I don't see any reason to mess with the z-ordering.

[kathy-phet]

@samreid - The dog can still be occluded -- is this expected?

Also, I noticed that he doesn't yelp until he has a 10K voltage across him - is that expected? I would think he would be electrocuted (as in die) at a lower voltage?

[kathy-phet]

I would think a reaction of a yelp at around 110 or 120 volt would be appropriate? https://petcosset.com/can-electric-fence-hurt-dog/

Q: How many volts will kill a dog?

A: It’s not actually the amount of volts, but the length of exposure that will kill your dog. For example, a 110-volt fence will not kill your doggo if it only touches it for a split second. However, if the doggo touched it for 30 seconds, it would surely kill the pooch.

[samreid]

@arouinfar and @kathy-phet and I set the threshold to Voltage of 100 V instead of a current of 0.1 Amps. Leaving open as a reminder to notify the client after this is published.

[samreid]

This has been published, @oliver-phet can you please notify the client? Close when complete.

[oliver-phet]

Ok, I've emailed the 3 users about the changes!