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phetsims / buoyancy

"Buoyancy" is an educational simulation in HTML5, by PhET Interactive Simulations.
GNU General Public License v3.0
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Full boat in fluids with a bigger density than the boat material #149

Closed DianaTavares closed 2 weeks ago

DianaTavares commented 2 weeks ago

I have to accept that I forgot for a moment of the fluid with a bigger density than the boat material. After analyzing this situation (and playing a little bit with the simulation), I think that we need more information for the students:

image

1) the volume inside the boat is 8.88...L, which explains that the boat's weight changes from 29,4 N to 287.25 N, as displayed in the picture. But calculating that is not going to be trivial for most students. Then I go back to what @zepumph suggested some time ago, we need to tell them what the volume is inside the boat, and in that situation, I don't recommend a strange number as 8.888... L. Is possible to have something like 8.5? or at least 8.8? but the mass is 3 kg when the volume is 10? (to maintain the initial state).

image

2) the other number the user needs to make sense of is the buoyancy force (also 287.25 N). I am not sure what the information gives to the students to make sense of that number. The other screens have been showing students that they only need to make the operation: (density of the fluid)(gravity)(FLUID DISPLACED). The Fluid displaced is 9.9L in this case, not idea how the simulation can show them that value, or give them more information (from the pool) to deduce that value. From the 101.01 L I couldn't. The true is that I don't know where that 101.01L came from.

DianaTavares commented 2 weeks ago

now I know where that 101.01 L came from. With the %submerged indicating that 99% of the boat is submerged, well, the total volume of the boat's shell is 1.11L, then, the 99% is 1.098L. Probably we need the % submerged accessible (but close) by default.

DianaTavares commented 2 weeks ago

In the design meeting, we agreed that what the simulation is showing is correct, and that the screen is for advance learners that can be challenged to make sense to the forces numbers. I will add some information related to that in the teacher tips. Closing!