# Focus of the week:  Density

6.6(B) calculate density to identify an unknown substance

We have been working on how to measure the volume and mass of objects.  Students need to be able to make the connection that mass has to do with measuring using a triple beam balance with the unit of grams. Students need to know how to calculate the mass reading a triple beam balance.

Volume is measured using water displacement with a graduated cylinder and is represented by the unit mL  In order to find the volume, students must do the following:
1. measure the volume of the liquid in a graduated cylinder
2. drop the object that is needing to be measured into the graduated cylinder
3. measure the volume of the liquid after dropping in the object
4. subtract the volume of the two graduated cylinders--this will show how much water was displaced (volume of the object)

This week we will make the connection that if mass>volume, the object sinks; if mass<volume, the object floats.  Students will need to use the terms more dense (sink) or less dense (float) than water.

We will also begin calculating density using the formula:
density = mass/volume

Students will have homework each night this week to help practice density.
Students will need to study each night the material from class and will have at least 1 problem to reinforce density if they do not finish in class.

Friday is our quiz over density.