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 =Sink or Float- It's All About Density!=

= = ====Have you ever wondered why things sink or float in water? How many of us when we were little brought toys into the bathtub and took the toys that floated and tried to push them down to get them to sink? Well, it is all depends on the density of an object that determines whether an object will sink or float. Density is how much mass is contained in a given unit of volume. Density can be determined with the formula Density= mass/volume. This is a formula we can use in high school, maybe middle school but how can we use such a formula for elementary school students? This formula is too hard of a concept for elementary students to grasp therefore,we can use sink and float activities to determine what types of objects sink or float.====

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[|An interactive Game for Sink and Float] for further exploration! ====Whether you teach kindergarten or fourth grade, sink and float experiments are fun and get the children excited about science. In fact, you will see questions on sink and float onNew York State Science exam for fourth grade.====

=Changing Objects to Change Density=

====Another way we can introduce density on an elementary level is changing liquid solutions. We can look at real scenarios with our students that they may see on a regular basis. For example, we can bring in something as simple as a bottle of vinegar and oil salad dressing, shake it up and then put it on a table and have students watch the vinegar seperate from the oil. We can get them to hypothesize why this happens and let them take vinegar and oil, pour them both into a contain with a lid and ask them to try and get them completely mixed and stay together after vigorously shaking them. To tie math in, have the students measure out equal amounts of the two liquids.====

====A second way to change density is to change the fluid used to sink and float objects. For example, we can use plain water in one container and another container can use water mixed with another solution, such as salt or soap, and use 2 identical objects to see if the objects will both sink or both float. Students again should share a hypothesis before performing the experiment. Below is a sample lesson that can be used.==== [|density worksheet.pdf]

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