User request: vertical rulers

[oliver-phet]

It would be cool to have embedded vertical rulers within this sim to be able to measure the height above and below the water level. The rulers I am thinking of are like the ones in the "wave on a string" sim.

The scenario I have in mind is to have students predict the fraction of an object that is submerged (or floating). The sim portrays this nicely. I am hoping its accurate enough that students can test their prediction for various materials.

In the absence of a virtual ruler, a real ruler placed on the screen may work.

[DianaTavares]

Students can predict the fraction of an object that is submerged as the way the simulation is in this moment by using the pool level indicators.

Using a ruler to measure this is risky because they are using a 1D measure (high) to compare 3D measures (volume). Then this comparison only works with cubes, and I don't think that students can do this relationship of "comparing highs only work with cubes" in the simulation.

@oliver-phet hope this answer is enough for the user feedback. Thanks!

[oliver-phet]

Replied to user.

[DianaTavares]

I think that this suggestion can be useful as another way to approach a volume in the sim.
Now, the user can measure volume by sinking the block in the water, but I remember some teachers sharing that would like also to have the traditional way of measuring/calculating volume (measuring sides of the block and using the volume formula). This is not fully possible in the sim because one of the dimensions is not accessible, but in density all the blocks are cubes, then users can really calculate volume by measuring only one of the sides with a vertical ruler.

If we include the vertical ruler I think we can win:

• support students to build a dipper idea of "volume"
• support student in the necessity of conversion of units, because the rule is going to be in cm and the volume value in the sim are L
• during the interviews, I saw that most students know that they need to put the block in the water to know the volume of it, but not all of them know that need to sink all the blocks in order to have the full volume of the block. The ruler can support students to discover that the full process of measuring volume with the Arquimedes principle.
• compare two methods to find one value (in this case volume) where one is more exact than the other. Physics is about measuring, having an activity to reflect about the comparison of a traditional method (use a formula) vs an indirect method (with the water), I think is important.

now is not possible to include this in the sim, but in the design meeting on December 16, 2021, was decided to leave this issue open for future improvements in the sim. I leave this mockup as an idea:

[zepumph]

Today the Buoyancy team decided this is not worth pursuing in Buoyancy a ruler, it is more of a Density-specific item. We are going to create a separate issue to add tick marks to the blocks to more easily find the percentage underwater. I'll remove this from the Buoyancy project board right now.