Sink or Float

We talked about the pirate ships sailing on the seas.  We were able to discover that the oceans are salt water, where as lakes and rivers around us are made of fresh water.  We conducted an experiment to see if things would float or sink in the different kinds of water.















They discovered that the beads would float on top of the water when dropped into the salt water, and sink when dropped into the fresh water. One student made a video using the ipad documenting his experiment.  Some other students, drew pictures showing what happened.

Look closely, you can see the bead at the bottom of the "plain" water bottle, and the heart shaped bead is floating in the salt water.

We discussed as a class why they thought this happened.  It was so interesting to hear their speculation.  Some explained it that the salt made the water "heavy" and therefore it pushed up the beads.  Others explained it saying, "the salt in the water pushed the beads up". One student said that there were molecules in the water, and the salt made more air molecules and that is what made the beads float!!!  Back to science class for me!