Hot or cold? Chemical Reactions

About the Activity

In this experiment, kids will use common kitchen ingredients to create and observe two different chemical reactions!


Grades: 4-8
Topic: Chemistry/Math
Estimated Time: 45 minutes

4-H STEM Lab Logo

What You'll Need

Pantry Staples

  • White Vinegar
  • Baking Soda
  • Steel Wool
  • Small Bowl
  • Sealable Freezer Bags
  • One Tablespoon Measuring Spoon
  • 1 Cup Measuring Cup
  • 1/4 Cup Measuring Cup
  • Paper Towels

Special Supplies

  • Pocket Food Thermometer
  • 1 Quart Glass Canning Jar with Lid
  • Kitchen Timer or Stopwatch

Activity Steps

  1. Place the thermometer in an empty freezer bag and seal it. Allow the thermometer to set for 5 minutes and record the temperature.
  2. Remove the thermometer and pour 1⁄4 cup(2 ounces) of vinegar into the bag. Place the thermometer back in the bag, seal it, and after 5 minutes, record the temperature.
  3. After recording the temperature, unseal the bag (leaving the thermometer in) and pour in one tablespoon of baking soda (premeasured) and quickly reseal the bag.
  1. After 2 minutes, record the temperature and compare it with the first temperature reading of just the vinegar itself.
  2. Place the thermometer in an empty glass canning jar and put on the lid. Allow the thermometer to set for 5 minutes and record the temperature.
  3. Pour 1 cup of vinegar into the small bowl and soak the steel wool in the vinegar for 1 minute. Squeeze the excess vinegar from the steel wool.
  4. Remove the thermometer from the jar. Wrap the soaked steel wool around the measuring end of the thermometer. Place the steel wool wrapped thermometer back in the jar and quickly put the lid back on.
  5. Observe the jar for 5 minutes. Do you see any reaction happening in the jar? After 5 minutes, record the temperature (without opening the jar) and compare it with the temperature reading of the empty jar.
girl works on 4-H at Home chemistry experiment

Questions to Engage Youth

  1. What was your hypothesis about the two reactions?
  2. What was the temperature change in the first reaction?
  3. What happened to the sealed freezer bag? Why do you think this happened?
  4. What was the temperature change in the second reaction?
  5. What did you observe about the sealed canning jar? What was formed inside?
  6. What did you notice when you opened the canning jar?
  7. Did any of your senses notice anything different? Were you surprised by the results?


Through the process of a chemical reaction, energy (in the form of heat) can sometimes either be given off or taken in. The technical terms for these types of reactions are exothermic (giving off heat) and endothermic (taking in heat). Most of the time when we think of heat given off, we think of fire or an explosion which can be a very spectacular reaction. On the other hand, when we think of heat taken in, we think of something getting cold, very slowly.


In this experiment, we tested the hypothesis that exothermic reactions are big and spectacular and endothermic reactions are relatively boring. The very quick and spectacular reaction between vinegar (Acetic Acid – CH3COOH) and baking soda (Sodium Bicarbonate – NaHCO3) produced Sodium Acetate (C2H3NaO2) and Carbon Dioxide (CO2). In doing this, the reaction took in heat from the surrounding atmosphere, making it endothermic. By producing CO2, it also inflated the sealed freezer bag.


In the second half of the experiment, soaking the steel wool in vinegar (Acetic Acid) actually helped dissolve the protective coating on the steel wool allowing the Iron (Fe) in the steel wool to be exposed to Oxygen (O2) and Water (H2O) in the atmosphere. When these three chemicals combine, Iron (III) Oxide (Fe2O3)or “rust” will be formed. In the chemical reaction of iron rusting, heat will be given off, making this an exothermic reaction. But the reaction is not nearly as spectacular as the vinegar and baking soda endothermic reaction.

Download the Hot or Cold? Chemical Reactions Activity

Share this activity   

Additional Activities

celebrity chef and author Carla Hall teaches 4-H'er to cook

Brought to you by:

No endorsement of these supporters' products or services is granted or implied by 4‑H.

Explore STEM Resources from Shop 4-H

If you enjoyed this activity, you can find more STEM learning resources and products on

Computer Science and Programming curriculum from Shop 4-H

Discovering Computer Science Level 1

Grades: 6-8


Learn the fundamentals of computer programming with this fun beginner's guide to Scratch, a project of the Lifelong Kindergarten Group at the MIT Media Lab. Youth walk through engaging activities and tutorials in this pdf workbook.


Circuits and Electrical Engineering curriculum from Shop 4-H

Explore a Power Park Book 1: Paper Circuits

Grades: 3-12


Using LED's and conductive tape, young engineers can learn the ins and outs of electric circuits with this activity, which include short tutorials and background information that accompany puzzles and challenges.


Wind Power activity from Shop 4-H

Wind Lift Activity

Grades: K-12


Harness the power of the wind with this activity that takes youth inside energy, mechanical advantage, torque, work, and other scientific concepts. The kit includes all the materials you need to build a wind lift, including a reamer tool.


Super Wiggle Bot robotics activity from Shop 4-H

4-H Super Wiggle Bot

Grades: K-12


Wiggle-Bots are motorized contraptions designed and built entirely by kids. Watch eyes widen as wires are connected and Wiggle-Bots start to move. See how understanding and design evolves through experimentation and tinkering. Stretch youths’ STEM skills with this activity.


Build a Boat engineering design activity from Shop 4-H

Build-A-Boat Activity

Grades: K-12, Youth 12 and under require adult supervision.


Dive deep into this boat-building activity to explore concepts such as buoyancy and power. In this activity using everyday supplies, youths design an electric motorboat. Create unique propellers by changing blade shape, angle and number.


hydraulic claw engineering activity from Shop 4-H

Hydraulic Claw Activity

Grades: K-12, Youth 12 and under require adult supervision.


Make your own arcade at home! Design and build a hydraulic claw that works just like the games in an arcade. Move the upper cylinder and watch your claw open and close below.



Help Kids Continue Learning During COVID-19