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Heating Crystals
Administration Procedures
Contributed by: Assessment of Performance Unit (APU)


Students examine the effects of heating on various crystals.

Questions in the observation category assess pupils' ability to use a variety of senses to observe data in a certain way- a scientific way. All observing is selective and guided by a purpose. The general purpose in this test is that shared by scientists: discerning regularities, similarities and differences, patterns of various kinds and significant or systematic changes with time.

The assessment reflects a view of observation as the collection and interpretation of real data where little or no initial filtering out of detail has been made. For this reason observation is tested by a variety of practical tasks.

This task is designed to take students approximately 15 minutes to complete.

Overall Task Content Area:

Physical Science

Specific Knowledge Areas:

Properties and changes of properties in matter

Performance Expectations:

  • conducting investigations
  • using equipment
  • gathering, organizing, and representing data

National Science Education Standards:

12 A SI 1: Abilities necessary to do scientific inquiry: Grades 9-12
1.4 Formulate and revise scientific explanations and models using logic and evidence. Student inquiries should culminate in formulating an explanation or model. Models should be physical, conceptual, and mathematical. In the process of answering the questions, the students should engage in discussions and arguments that result in the revision of their explanations. These discussions should be based on scientific knowledge, the use of logic, and evidence from their investigation.

8 B PS 1: Properties and changes of properties in matter: Grades 5-8
1.2 Substances react chemically in characteristic ways with other substances to form new substances (compounds) with different characteristic properties. In chemical reactions, the total mass is conserved. Substances often are placed in categories or groups if they react in similar ways; metals is an example of such a group.

(Use the "hot" link on the PALS home page to check the full text of related National Science Education Standards, if desired.)

General Instructions to the Teacher:

This task is designed to take students approximately 15 minutes to complete.

Students will be working individually during this exercise.

Students should be ready to work as soon as the period begins.

Materials for "Heating Crystals":

  • Test tubes containing 1 cm depth of solids P, Q, and R.
    • P  =  Nickel Sulfate
    • Q  =  Copper Sulfate
    • R  =  Iron Sulfate
  • 1 test tube rack
  • 1 test tube holder
  • 1 bunsen burner
  • 1 mat
  • 1 box matches
  • 1 container labeled "dirty test tubes"
  • goggles

Advance Preparation:

  • Label three test tubes for each station "P", "Q" and "R."
  • Fill tube P with Nickel Sulfate to 1 cm depth.
  • Fill tube Q with Copper Sulfate to 1 cm depth.
  • Fill tube R with Iron Sulfate to 1 cm depth.


  • Be careful.
  • Teachers and students should always exercise appropriate safety precautions and utilize appropriate laboratory safety procedures and equipment when working on science performance tasks.


  • N/A


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