chemistry
Question:

The important relationship in the connection between the flotation of the elements is their density which defined as the relation between the mass of the element and his volume.

Examined the following simulation, wach the  video and then answer the following question.

https://phet.colorado.edu/sims/density-and-buoyancy/density_en.html

https://www.youtube.com/watch?v=ShoBxocHB58

The question

If we put the chickpeas in a sparkling water , the chickpeas will sink to the bottom of the bowl , and they will float to the top of the bowl again and this will be repeated again and again 

We have co2 ,water and chickpeas in the bowl according to the above video

Why do chickpeas always float and sink? 

0 People tried to answer this question

The applied pressure by carbon dioxide on chickpeas is equal to that applied by water, as a result chickpeasalways float and sink.

Carbon dioxide applies pressure on chickpeasfrom the bottomtherefore they float. When they rise, air applies pressure on them then they sink. It is a repetitive process.

Carbon dioxide accumulates at the chickpeas surface as bubbles, thus chickpeas density decreases and they float. When chickpeas rise, the bubbles blow out and carbon dioxide goes to air, their density increase and they sink. It is a repetitive process.

Water density is equal to chickpeas density, thus theyalways float and sink.



Comments:
1.  Abu alheja Shorouq (2007-12-20 15:00:00)
density

the beginning of the question is very good: definition of density, relation between density and mass ,volume..

I like the experiment video, the simulation was useful, and I think that you write a great question which is understanding and analysis question.  

I think that the connection made between "density" and Archimedes is remarkable. But I also think that chickpeas in a sparkling water and submarines work in similar way (floating and sinking is like diving and surfacing). You can teach the students through this example that the study of density can be used in real life.

2.  dahan mor (2014-12-20 15:00:00)
chemistry
A very good question. The question is well explained and the simulation contributes a lot for understanding.
Your question contains also understanding and analysis and its great.
In addition, the question is related to everyday life and to the world of students.
In my opinion, you should change a little the answers to be more tricky answers.
Good luck!


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