My PBL Project

INTRODUCTION:

• To see how long it takes for hand warmer not exposed to oxygen to heat up compared to a hand warmer exposed to oxygen.

• To discover what chemical reaction goes on inside the hand warmers that cause them to become warm.

Hand warmers are used throughout the world as a use f great warmth especially in cold areas or during chilly activities. The hand warmers i used contain, Iron powder, Water, Salt, Activated charcoal, and Vermiculite. These hand warmers can heat up to 140 degrees Fahrenheit and even hotter.

MATERIALS:

• Cup

• Scissors

• Stopwatch

• 2 Hot hands Body & Hand Super Warmers

• Thermometer

PROCEDURES:

1. Unwrap both Hot hands Body & Hand Super Warmers; do not activate either one.

2. Activate only one of the hand warmers and start timer immediately.

3. Keep timing until hand warmer reaches 140 degrees Fahrenheit

4. As you cut off the top part of the second hand warmer start timer and pour contents into a cup. Stop timer after warmer reaches 140 degrees Fahrenheit.

5. Compare the time differences between both experiments.

SCIENTIFIC PRINCIPLE:

Lesson: Exothermic reactions produce heat

What will happen:Iron powder will begin oxidizing (rusting) when exposed to the air, becoming hot.

Hand warmers contain cellulose, iron, water, activated carbon, vermiculite and salt and produce heat from the exothermic oxidization of iron when exposed to air. When a reaction is endothermic (absorbs energy - heat) in one direction, such as the reduction of iron oxide to elemental iron, it will be exothermic (give off energy) in the reverse direction, the oxidation of elemental iron back to iron oxide.