Density & Buoyancy 

 What causes something to sink or float?

NGSS Performance Investigations

3-PS2-1. Plan and conduct an investigation to provide evidence of the effects of balanced and unbalanced forces on the motion of an object

Solids & Fluids

(1) Look at the objects you have been given and predict if you think they will sink, float or remain suspended (neutral buoyancy).  Record your predictions.  After everyone has submitted their predictions, compare the class predictions and identify those objects whose behavior was most difficult to predict. (See summary data)

(2) Form combinations of blocks (see photos) by tying them together with rubber bands such that the total mass of each combination is less than 120g.  Find one combination that will float and one combination that will sink for each of 1-block, 2-block, 3-block, 4-block and 5-block combinations.  Determine the masses of each combination and record in the appropriate column of the data table.  You may mix blocks from the various sets and use more than one of each material when making combinations. 

After analyzing your data and the class data, please answer the following questions.  Generate a scatterplot of the data

VIDEO: Creating a Scatter Plot [6:49]

Dissolved Solutes

Measure the mass and volume of a diet and regular soda.  Based upon your measurements, do you think diet will float or sink?  How about regular soda?  Enter your prEdictions in the QuickWrite.   Were your predictions correct? If not, why do you think so?

Temperature

What effect does temperature have upon the m/v ratio of a fluid?  Compare  hot & cold water.

Applications to everyday life

Molecular Size in Gases

The atmosphere is approximately 79%  N2  and 20% O2 .  Predict what will happen if you mix carbon dioxide with air.  Refer to the periodic table.