This was a simple little trick to get a kid to take her medicine, but it worked so well, I thought it was worth sharing.

My six-year-old daughter Ayelet was sent home from school with a fever on Tuesday. They gave her some tylenol which seemed to get it under control, and by the next morning she was mostly better. However, she still had a mild fever, so we kept her home Wednesday out of an abundance of caution (and the fear of being “that parent” that sends their sick kid back to school).

By Thursday, she was back at 100% and definitely ready to go back. I just wanted to make sure she took one last dose of Ibuprofen before going in case she had any mild residual fever. According to the packaging, she needed to take a 2 tsp dose at age six, so I measured it out and handed it to her.

2 tsp isn’t a lot of medicine, but it fills up the measuring spoon.

And thus began the standoff.

“It’s too much!” she wailed.

“Ayelet, it’s just two teaspons!”

“But I don’t like it! I can’t drink that much!”

And around and around we went. I suggested just taking small sips. I suggested just guzzling it down and getting it over quickly. She wouldn’t budge. The argument dragged out for over five minutes. I needed her to take her medicine, finish her breakfast, and get in the car to go to school, and we needed to move past this quickly.

Then, I had a sudden flashback to my 9th grade geometry class. I don’t remember why it came up, but the teacher mentioned that kids of a certain age don’t have a proper sense of volume. Adults understand that 10 milliliters of liquid is always the same amount, no matter what container you put it in, but kids will think that narrow container has more because the liquid rises higher.

Ayelet has reacting to the fact that it was too much medicine. Was she old enough to know that the volume was the same if I put it into a different container? Was this random factoid from 9th grade even true?

As my daughter watched me, I grabbed a juice glass from the cabinet and poured the medicine in. It formed a tiny puddle at the bottom of the much wider cup.

2 teaspoons fills the measuring spoon, but it just forms a tiny puddle in the much wider juice glass

“Here,” I said as I handed it to her. “It’s just tiny bit.”

“Okay,” she said, and gulped it down.

Hmm. I guess my geometry teacher was right. Problem solved.

I went and looked it up, and it’s true. The concept is called “Conservation of liquid and number”, and the ability kicks in at around age seven. Ayelet was still young enough for the trick to work. In another year, I might be out of luck.

Normally I am all about teaching my kids about science, but perhaps I’ll keep this one a secret until they are a little older.