Well, I came to ask you a question. Why is there water on your face?
Barnaby and Barney (Pt 2)
Oh, that is because the snow and ice on my face melted to water. Do you know what type of change is that?
No. And what is the difference between a Physical and Chemical change anyways?
Barnaby and Barney (Pt 3)
Yes. I know, it might seem weird, but snow is just frozen water. The molecules are still made up of water.
Oh, okay. Since you already know the two types of changes, it won't be too hard. A physical change is a change where the chemical makeup of the substance does not change. For example, the snow melting was a physical change.
Barnaby and Barney (Pt 4)
Barney comes inside after playing in the snow.
A chemical change is where the chemical makeup of the substances does change. For example, when water hits the iron on the oven, the iron rusts. That is a chemical change.
Okay, but how do I tell when it is a chemical change?
Barnaby and Barney (Pt 5)
Yes! But why?
Now let me quiz you. Is the souring milk in the refrigerator a physical or chemical change?
A chemical change right?
Barnaby and Barney (Pt 6)
Great job, Barnaby!
There are a few ways to tell a chemical change. A change in color, a change in smell, the formation of a gas, the appearance of a precipitate, or a change in light.
Well, the milk smells horrible now, thats a change in smell. Also there are new molecules added with the change, and the process can not be reversed without special chemical methods.
Remember, today we learned about changes and the difference between physical and chemical changes. See you next time!