EDINA, Minn. - The timer beeped, and Liz Lee Heinecke handed her 13-year-old daughter, Sarah, two oven mitts. Her latest science experiment was ready.
Sarah opened the door of the oven and took out a silvery pan containing the result of a chemical reaction that demonstrated how heat turns water into steam: popovers.
Heinecke plucked one of the eggy rolls from a large muffin tin and tore it open so steam shot out of it. Then she slathered on a bit of butter and took a bite.
"Edible science," Heinecke said with her mouth full.
Her popovers - airy buns that rise without a leavening agent due to the steam that forms when putting liquid batter into a hot pan - represent only one recipe in a book full of ways to teach children about scientific principles, while also making dinner.
Heinecke is the author of "Kitchen Science Lab for children: Edible Edition" (Quarry, 144 pages, $22.99). It's the author's fifth book that helps parents utilize common objects found in the home to educate children about chemistry, biology, botany and more. While her previous books' lessons yielded more crafts and playthings - glue-based slime and self-inflating balloons, for example - her latest book contains step-by-step instructions with edible results.
"Cooking and baking are science," Heinecke said in her kitchen while she waited for the popovers to rise. "Once you understand the basics - you can add an acid and it makes it taste a little sour and brings out the salt - it becomes second nature. So then you can say, 'I know this experiment is going to work.'"
A living room end table stacked with books has her favorite, "Salt, Fat, Acid, Heat" by Samin Nosrat, on top. Where that book dives deep into the principles of each of those four aspects of cooking, so does Heinecke's, but on a pint-sized level. Every recipe includes a sidebar where Heinecke explains "the science behind the food."
She discusses tomatoes' chemical properties that give them their color and flavor alongside a Marcella Hazan recipe for tomato sauce. Gluten's elasticity is the topic in a recipe for pizza dough, and emulsions are demystified in Julia Child's recipe for beurre blanc. Young cooks working their way through the book aren't just learning how to make a dish; they're learning how cooking works.
"I think it's good for children to do stuff like this, because then they're not afraid of tackling recipes," she said. "You know, 'You can do anything.'"
Heinecke herself grew up unafraid of the kitchen. Her mother ran a cooking school in their home in Manhattan, Kansas. "We had a center island before center islands were cool," Heinecke said. She also grew up around science, with a physicist dad.
She became a biologist, doing bacteriology research. She was working in a lab on the day she went into labor with her first child, Charlie. He's now going off to college.
Heinecke pivoted to the stay-at-home mom life with Charlie and two daughters, May and Sarah.
"When you're with children, you're always looking for stuff to do," she said. She began infusing science into their activities, like examining bugs and plants outside. Each kid got their own notebook to record their experiments.
Home-science education helped her in school, said May, who is 17. "They'd be like, 'What's a polymer?' and I'd go, 'Oh yeah, I know!'"
Applying science practically at home lets children approach a big topic without the pressure or time constraints of school. "It gives them the opportunity to be creative and to make mistakes and no one is judging them," Heinecke explained. "I think science in school is essential and important, but it's really a different kind of science."
Heinecke began blogging about her experiments. "No one else was writing about how to do science with your children without making 20 trips to the store or having to buy an expensive kit," she said. Her blog led to an invitation to do a science-themed spot on a local morning TV show that turned into a regular gig.
In 2014, she wrote her first book in the series, "Kitchen Science Lab for children." The "Edible Edition" came out this summer, and Heinecke is at work on her next two: One focuses on chemistry and another on biology. She's also penning a narrative nonfiction book about Marie Curie's friendship with a theatrical lighting designer, slated for 2020. It's called "Radiant: The Dancer, the Scientist and a Friendship Forged in Light."
"It's funny," Heinecke said. "You just do what you love doing and life takes you on these trajectories."
After devouring the popovers, Heinecke and two neighborhood children got to work on more experiments from her books. First, they learned about the crystalline structure of tempered chocolate by melting candy bars, dipping balloons into it and making bowls for ice cream.
Then, they took the purple water that's a byproduct from boiling red cabbage and used it as a pH indicator. They changed its color by adding baking soda (a base, the water turns blue) and vinegar (an acid, the water turns pink), and then mixed the two solutions together to make bubbly purple volcano.
Chocolate streaks, scattered sprinkles and fizzing water were all over Heinecke's countertops. There was only one thing left to do.
"After you do a science experiment," Heinecke asked the girls, "what is the best way to make sure your parents let you do it again?"
Divya Thamann, age 9, answered promptly.
"Clean up."
Chocolate Domes And Bowls
Makes 10 to 12.
Note: Do not serve these to anyone with a latex allergy.
10 to 12 (5-inch) round balloons
12 ounces semisweet chocolate
4 ounces white chocolate, optional
Sprinkles, optional
Blow up the balloons. Set glasses or ramekins on a baking sheet.
Chop the semisweet chocolate into small pieces.
Melt the chocolate in the microwave for 30 seconds at a time, stirring for 30 seconds in between each heating until just melted and smooth. Alternately, melt the chocolate in a pan over a larger pan of simmering water. The chocolate should not be too hot or it will melt the balloons.
Chop the white chocolate into small pieces and melt as you did the semisweet.
Put the melted semisweet chocolate in a bowl slightly larger than the balloons and dip the untied end of the balloon in, coating the lower third of the balloon with chocolate.
Flip the balloon over onto a ramekin or small glass to cool, keeping the chocolate on the top of the balloon.
Spoon some melted white chocolate into a plastic zipper bag and cut off a tiny corner of the bag. Pipe the white chocolate in a design over the semisweet on the balloon.
Add sprinkles if you wish. Repeat with the rest of the balloons, reheating the chocolate if necessary.
Put the balloons in the freezer until the chocolate domes are solid and you're ready to eat them.
Remove the chocolate domes from the freezer. Pop the balloons and slowly pull them off the domes.
Use the domes as bowls for ice cream, or flip them over and hide a treat beneath.
From "Kitchen Science Lab for children: Edible Edition," by Liz Lee Heinecke.
Perfect Popovers
Makes 6 large popovers or 12 small ones.
Cooking spray, oil or butter for pan
2 eggs, room temperature
1 cup whole milk
1 tablespoon butter, melted
1 cup minus 2 tablespoons all-purpose flour
1/2 teaspoon salt
Lightly coat a popover pan or muffin tin with the oil, butter or cooking spray.
Break the eggs into a bowl. Whisk the eggs and milk together. Stir in 1 tablespoon melted butter.
Combine the flour and salt in a separate bowl, mix well, and then whisk them into the eggs and milk. Let the mixture rest at room temperature for around 1 hour.
Preheat the oven to 425 degrees. Pop the empty pan into the oven for about 5 minutes to heat the metal.
Fill the cups in the hot pan about halfway full of popover batter. Bake for 10 minutes on the center rack of the oven.
Lower the oven temperature to 375 degrees and continue baking until golden brown. Depending on the size of the pan, this will take another 25 to 35 minutes. Remove the popovers from the pan and serve hot with butter and honey or jam.
From "Kitchen Science Lab for children: Edible Edition," by Liz Lee Heinecke.