We are now beginning our unit on density and buoyancy and I like to use this learning activity to introduce density. Making students aware of their misconceptions is one of the most powerful methods in teaching science. When you demonstrate the actual reality of the concept it can break their misconception and students are forced to change their thinking. I give the students the following challenge statement (word document):

“Ojbects that are high in mass sink in water.”

Students have to write a paragraph stating if they agree, disagree, or are somewhat in between with the statement. They have to explain in detail their reasoning. It is not important that they are actually right or not, they just need to be able to clarify their thinking. I then do the following (see video below).

Afterward the students need to explain in a paragraph if their thinking has changed and if so, they need to explain how. The items that were used in the demo can be found at Educational Innovations. Here is a list of the items, with their masses and densities (excel spreadsheet).