This reaction causes the temperature to go up. Place 1 tablespoon of vinegar in a cup. Put the thermometer in the cup. Hold the thermometer and cup so they do not fall over. Read the temperature and ...
To test baking soda, drop half a teaspoon into a small amount of vinegar. If it fizzes, it's still active. If you don't get any sort of reaction, it's time to toss that box and buy some new baking ...