Gizmo Warm-up A chemical change. (or chemical reaction) occurs when one
or more substances, called reactants, are transformed into
different substances, or products. In the Chemical Changes
Gizmo, you will look for evidence of chemical changes by
looking at changes you can see, touch, or smell.
To begin, check that Reactant 1 is Sodium and Reactant 2
is Water. Sodium is a metal so soft you can cut it with a knife.
1. Click Play ( ). What do you observe?
2. Do you think a chemical reaction has taken place? Explain.

the increase of protons   hope this

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

water at room temperature is flowing through a pipe with pressure taps located 10 ft apart along one section of the pipe, which are connected to a mercury (s=13.6) manometer.