Materials: • one disposable plastic cup • one disposable plastic spoon (plastic fork or knife may be used instead) • thermometer (if you have one) • measuring cup and spoon • newspaper (use it to cover the countertop next to the kitchen sink. this could get a little messy! ) procedure: 1. pick one of the following combinations to investigate in this activity. a. vinegar and baking soda (nahco3) b. room temperature water and powdered washing soda (na2co3) c. vinegar and table salt (nacl) 2. measure two tablespoons of the appropriate powder (baking soda, washing soda, or table salt) and pour it into the clean, dry plastic cup. 3. measure out one cup of the appropriate liquid (vinegar or water). 4. if you have a thermometer, place it in the measuring cup of liquid and write down the initial temperature. 5. grasping the plastic cup near the bottom with one hand, pour the liquid into the plastic cup with your other hand. 6. continue to grasp the cup as you stir the solution gently with the plastic spoon. observe any temperature change felt through the plastic cup. 7. if you have a thermometer, record the temperature change as you stir the solution very gently. 8. when you are finished making observations, it is safe to pour the solution down the sink and to dispose of the cup and spoon in the trash. if you used a thermometer, be sure to wash it before putting it away.