8th Grade Mini Lab


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8th Grade Mini Lab

  1. 1. Exothermic Processes Mini-Lab Spring 2011 Davidson Student Volunteers for Science
  2. 2. Important!!! <ul><li>Please use this resource to reinforce your understanding of the lesson! Make sure you have read and understand the entire lesson prior to picking up the kit! </li></ul><ul><li>We recommend that you work through the lesson with your team prior to going into the classroom. </li></ul>
  3. 3. I. Introduction and Set-Up <ul><li>A team member should put the following vocabulary words on the board: endothermic exothermic chemical change physical change </li></ul><ul><li>Take time to explain “endothermic” and “exothermic”. See manual for detailed discussion. </li></ul>
  4. 4. II. Exothermic Chemical Processes <ul><li>Part A: Chemical (HotHands) Hand Warmer </li></ul><ul><li>Distribute the HotHands hand warmers to every other pair and tell students to share among two pairs. </li></ul><ul><li>Have one of the students tear open the plastic covering, take out the hand warmer, shake it, and put it aside until they do Part B. </li></ul><ul><li>Students should also save the plastic covering. </li></ul><ul><li>NOTE: The directions on the plastic covering suggest waiting, but students will be able to feel warmth from the hand warmer after about ten minutes. </li></ul><ul><li>HAVE STUDENTS GO ON TO PART B WHILE THEY ARE WAITING FOR HAND WARMERS TO GET WARM. </li></ul>
  5. 5. III. Exothermic Physical Processes <ul><li>Recyclable Hand-Warmer - Show the class a EZHeat hand warmer that contains a supersaturated sodium acetate solution. </li></ul><ul><li>Show the class a EZ Heat Reusable hand warmer that contains a supersaturated sodium acetate solution. Ask if any of them have seen one before. Have students see that handwarmer is liquid. </li></ul><ul><li>Pass around the handwarmers to the groups. Have a volunteer in each group bend the metal activation button. Students should see white solid beginning to form around the button. </li></ul><ul><li>Point out that the hand warmer can be recycled by placing it in a pan of hot water for several minutes. </li></ul><ul><li>Ask the students to explain how the EZHeat hand warmer illustrates the law of conservation of energy. (Heat energy is released when the button is pressed, which causes crystallization of solid from the solution. Heating in boiling water is required to restore the hand warmer, which requires input of heat energy.) </li></ul><ul><li>WHEN FINISHED, COLLECT ALL HAND WARMERS AND RETURN TO THE KIT BOX </li></ul>
  6. 6. IV. Exothermic Chemical Processes (cont.) <ul><li>Checking the HotHands Hand Warmer </li></ul><ul><li>Tell the class that the “missing ingredient” that is needed to make the hand warmer warm up is oxygen. When the plastic covering is removed, the inside pouch is porous enough to allow air to enter the pouch. The oxygen in air reacts with iron to form iron oxide with the release of heat. The HotHands hand warmer is an exothermic chemical reaction that occurs when powdered iron is mixed with activated carbon, water, salt, and vermiculite in the presence of air. </li></ul><ul><li>Take the empty 4 oz jar, cut open a hand warmer pouch and pour the contents inside the jar. Let the students look at this jar and compare what the contents look like with the jar that contains contents of a HotHands hand warmer that were exposed to air for 24 hours. </li></ul>