Fifth Grade, Chemistry

You are given: water, vinegar, baking soda, and salt.

1. Select two of these materials to put into a cup to produce a physical change. Give at least one reason why this was a physical change.
2. Select two other materials to put into another cup to produce a chemical change. Give at least one reason why this was a chemical change. 

Student Work A

"I would use vinegar and baking soda for a chemical change because the mixture bubble up. Another reason is you can't get the baking soda back out of the vinegar. Another way is a chemical change is that the chemical changes into a gas.

I pick salt and water for a physical change because they do not bubble up. Another reason is that they chemical does not change it stays the same. Another reason is that you can get the stuff back."

Level 4: student selects materials for the chemical and physical changes and includes more than one reason for each.

Student Work B

"Two materials that causes a physical change are water and salt. This is a physical change is when you mix water and salt, the salt dissolves in water. But, you can bring the salt back by evaporating. You put the salt-water on a window sill and the water will evaporate leaving the salt. This is a physical change because you can get out materials that make the product.

Mixing baking soda and vinegar makes a chemical change. This is a chemical change because if your mix them together, making bubbles. A chemical change is when you mix something together to make something new."

Level 3: student selects materials for the chemical and physical changes and includes one reason for each.

Student Work C

"A physical change is a change when you can get some thing back. If you use sald and water. I can get back the salt by putting the salt and water on window silk. The water will evaporate leaving only the salt in it same place.

A baking soda and vinegar will change size. The baking soda and vinegar will bubble up in to a chemical change."

Level 2: student selects materials for the chemical and physical changes and includes an acceptable reason for knowing it is a physical change; the reason for a chemical change is too weak to be acceptable.

Student Work D

"I think that vinegar and Baking Soda are a chemical change because they make bubbles and sometimes it can explode. I think a physical change is water and salt because the salt says under the cup they they make little little bubbles."

Level 1: student does not explain the chemical change nor the physical change.