Science Smarts: Molten lava

By PATTY ROOKS on January 14, 2023.

This week, I have a fun experiment that will make you wonder if you are really learning about science.

When I do this activity, I often think it looks like hot molten lava…and trust me; it is probably as hot as lava. It is a great activity to get the entire family involved on a cold winter day; just make sure you help out those younger scientists in the kitchen.

Let’s get started!

Remember to ask an adult before doing this experiment.

Materials

• Stove

• White sugar

• Corn syrup

• White vinegar

• Baking soda

• Cooking spray

• Measuring spoons

• Measuring cups

• Wooden spoon

• Candy thermometer

• Rimmed baking sheet

• Saucepan

Procedure

• Spray the rimmed baking sheet with cooking spray. Set aside for now.

• I would recommend having an adult help you with the next few steps.

• Measure 250 mL (one cup) of white sugar and pour into the saucepan.

• Add 250 mL (one cup) of corn syrup to the sugar and 3 mL (two tablespoons) of vinegar. Stir well.

• Place the saucepan over medium heat and constantly stir the mixture.

• Have your helper measure the temperature of the mixture every minute or so ONCE it starts boiling.

• Once the mixture reaches 155°C (310°F) remove it from the heat and place on a sturdy counter.

• Measure and add 15 mL (one teaspoon) of baking soda to the mixture. BE CAREFUL as it is going to foam up a little bit.

• Ask your helper to pour this mixture onto the baking sheet.

• Allow the mixture to cool completely before you try it – it is HOT!

What is going on?

I absolutely love science experiments like this as you are doing something fun (not to mention delicious) and also learning. It is a great way to get the entire family involved in the fun (and learning)!

When you added the chemical sodium bicarbonate (baking soda) to the mixture, I am sure you were taken by surprise. What an eruption! I always am amazed at how this little mixture can expand so much. Did you know this is not just a delicious activity, but there is some science involved here! The molten HOT lava sugar mixture reacts with the baking soda you added. I am sure you saw and heard the carbon dioxide being released. The carbon dioxide bubbles for a little bit in the mixture, causing it to expand (as you observed). When it cools down, it hardens and the spots where the bubbles were remain, making it a hard and crunchy treat!

Teachers – if your school is interested in having a science fair club, make sure you call soon so I can pop by and give you some great pointers!

Patty Rooks, Senior Scientific Consultant PRAXIS, “Connecting Science To The Community”. Contact Praxis at praxis@praxismh.ca, http://www.praxismh.ca, Tweet or follow us @PraxisMedHat, or friend us on Facebook. Address: #12 826 11 Street S. E., Medicine Hat, Alberta, T1A 1T7 Phone: 403.527.5365, email: praxis@praxismh.ca.

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