This Friday (June 11) we will explore the eruptive realm of acid-base chemistry in our new children’s video series: Summer School with Live Science.
This week, Live Science producer Diana Whitcroft will demonstrate the reaction between them sodium bicarbonate (baking soda) and citric acid (in this case lemon juice). This fun experiment is a great way to introduce young minds to the world of chemistry.
Every Friday at 15:00 EDT (12:00 PDT), Diana will host a Summer School of Live Science, which you can find live on the Live Science Facebook, YouTube and Twitter pages. Each week the series will explore a different area of STEM (science, technology, engineering and math) through simple practical experiments that you and your child can follow at home.
Disclaimer: It is strongly recommended that all scientific experiments, recipes and methods be tried only under adult supervision. Adults should handle or help with potentially harmful utensils and ingredients. Always wash your hands thoroughly after trying an experiment. Avoid touching your face and eyes when experimenting, and if possible, wear glasses or goggles. Do not ingest any of the ingredients during or after this experiment.
Lemon volcanoes: Materials
Age group: 5-1
- Tray or cookie sheet
- Paper (optional)
- Cutting knife
- Stick from Popsicle
- Food colors
- Dish soap
- Baking soda
Step One: Prepare your workstation
Place your tray on a surface that has been well covered with newspaper. Optional: Place paper on your tray; here you will erupt your volcanoes and if the paper catches the colored liquid, you can turn it into a work of art.
Step two: Prepare your lemon
Have an adult cut off a small portion of the bottom of the lemon so that it stands upright. Then cut off the top of the lemon, exposing the inner mass and juice. Using your pasta stick, mash the inside of the lemon so that the “meat” or flesh inside is completely pushed down and the lemon is mostly filled with juice. Be careful not to pierce the lemon peel.
Step three: Choose a color
Squeeze a few drops of the food coloring into the lemon. The amount of food coloring you use depends on the size of your lemon and how much juice it gives. Small lemons with very little juice: 2-3 drops. Large lemons with lots of juice: 4-5 drops. Try different color combinations and see what comes out! You can even erupt two or three lemons at a time for a paper coloring effect. Then put a good syringe of dish soap in your lemon.
Step four: Erupt your volcano
Using a spoon, sprinkle a few teaspoons of baking soda in your lemon. Again, depending on the size of your lemon, you will need to adjust the amount. Small lemons with a little juice: 2-3 tsp. Large lemons with lots of juice: 4-5 tsp. You should see rustling and gurgling right away, but you may need to use your spoon or stick to mix the juice and baking soda better. Now your lemons will start overflowing with colored bubbles.
Document this experience and send us images either on social media or at firstname.lastname@example.org. We will be happy to see your results so we can present them in our photo gallery!
Step five: Draw!
Now that the explosive fun is over, it’s time to get creative. Using your hands, a paintbrush, or even a sponge, create your own artwork from the colored liquid left on the paper. Just remove your lemons and go to town! Make sure you do not repaint your paper. Combining your colors too much will turn your color canvas into a big gray spot (unless of course you really like the gray color!).
The science behind lemon volcanoes
When the baking soda was added to the lemon juice, it began to foam and foam. This is because when sodium bicarbonate (baking soda) and citric acid (citric juice) are combined, they react to form carbon dioxide gas, as well as a chemical called sodium citrate. It is the carbon dioxide that causes all these bubbles (remember that CO2 is the gas that drives your canned soda or soda water). We know that carbon dioxide is the main gas we exhale when we breathe. It occurs naturally in the Earth’s atmosphere and is emitted by natural sources such as geysers (and volcanoes), as well as by industrial processes.
Sodium citrate is the sodium obtained from citric acid. Used in various everyday objects. It is used as an anticoagulant for blood products, as well as a regulator of acidity in food.