Chemistry: Baking Soda + Phenolphthalein & Water + Calcium Chloride

1. Add phenolphthalein & water mixture to baking soda -- color change (it turned magenta because baking soda is a base)
2. Add calcium chloride -- temperature change (mixture became really warm), formation of gas (bag expanded) , color change (changed back to white from magenta)

Chemistry: Dry Ice

Physical Change: Change in State of Matter

When a substance changes directly from a gas to a solid 

(example: the forming of frost from water vapor) 

or from a solid to a gas (examples: dry ice, solid air fresheners) 

it is considered a change of state and is called sublimation. 

This is still a physical change because the composition of the substance remains 

the same.

Chemistry: Limewater + Carbon Dioxide

Chemical Change: Formation of a Precipitate

When two solutions are combined, they may form a solid substance.

This solid substance is called a precipitate and indicates that a chemical change has occurred.

When carbon dioxide is combined with aqueous calcium hydroxide 

(limewater), solid calcium carbonate (chalk) is formed as the precipitate. The 

precipitate may be in the form of very small particles, appearing as cloudiness in the 

solution or as a solid which settles to the bottom of the container.

Chemical Equation:

Ca(OH)2 + CO2 → CaCO3+ H2O

(Limewater + Carbon dioxide → Calcium carbonate + water)

Chemistry: Burning Sugar

Physical Changes:

Change in State of Matter

When a substance changes from one state of matter to another and the

composition remains the same.

1. Started as a solid sugar cube
2. Melted into a liquid state
3. Cooled and returned to solid state 

Chemistry: Crushing Sugar

While crushing sugar we demonstrated a 

physical change, change in size and shape.