Observing Changes in Matter

Procedure - Part A

SAFETY: GOGGLES ARE TO BE WORN AT ALL TIMES!

1. Pick up one of the sugar cubes and observe it carefully. Describe the sugar cube in the terms of the

following properties:

  1. Size (L x W x H) ______
  1. Shape ______
  1. Color ______
  1. Taste ______
  1. Hardness ______
  1. Texture ______

2. Take one sugar cube and use the mortar and pestle to crush them into a powder. Pour the crushed sugar onto the piece of scratch paper.

3. Observe the powder. Describe in detail how have you changed the sugar?

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In what ways has the sugar not been changed?

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4. Take the crushed sugar and pour it into acup of water. Stir with the stirrer.

5. Look carefully at the mixture. Is the sugar still visible, explain? Now how has the sugar changed?

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6. Take a taste of the water (yes, drink it). Is the sugar still present? How can you tell?

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Procedures: Part B

SAFETY: GOGGLES ARE TO BE WORN AT ALL TIMES!

1. Take one sugar cube, crush it, pour into onto the scratch paper and then pour the crushed sugar into the test tube.

2. Light the Bunsen burner. Caution: Be very careful when lighting and using a Bunsen burner. Using the tongs to hold the test tube by placing it into the hottest part of the flame. Be sure to point the mouth of the test tube away from people.

3. Heat the test tube until the sugar burns/bubbles. Observe the contents of the test tube carefully as you heat it.

4. Remove the test tube from the heat and CAREFULLY and QUICKLY pour the contents carefully onto a sheet of foil.

5. Turn off the Bunsen burner. Carefully set the test tube back into the test tube rack.

6. Observe the contents of the sugar now on the aluminum foil. Describe the substance in terms of the following properties:

  1. Size (measure this) ______
  1. Shape ______
  1. Color ______
  1. Taste (CAUTION: Do not swallow the substance – It is sharp!) ______
  1. Hardness ______
  1. Texture ______

5. Recall the two sugar cubes that you started with. How has the sugar changed?

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6. Is the sugar still present in the test tube? How can you tell? (Hint: Are the propertiesof what is in the test tube now the same as before it was heated up?)

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Critical Thinking and Application

7. Compare and contrast the changes in the sugar that took place in Part A with the changes that took place in Part B. How are these changes the same? How are these changes different?

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8. The changes that took place in Part A are called physical changes, while the changes that took place in Part B are called chemical changes. Based on your observations, how would you define a physical change? How would you define a chemical change?

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Clean-Up:

  1. Clean up the test tube per your teacher’s instructions.
  2. Throw away foil with the burnt sugar (DO NOT leave the lab with this) and clean up your work station. All articles should be returned as you found them.
  3. Turn in your completed lab paper on the front desk.