On this page
"Why does the steel tumbler sweat when there's cold water in it?" "Where does the moon go in the day?" Questions like these come in the car, at dinner and at bedtime, and plenty of them are ones you can't answer. That's normal. As with helping with maths you've forgotten, your job is not to be the answer key. Your job is to show your child how answers get found.
Is it bad to tell my child "I don't know"?
No. A dead end is the problem, not the gap in what you know. In a 2009 Child Development study by Frazier, Gelman and Wellman, preschoolers who got a real explanation tended to agree and ask a follow-up question. Children who got a non-answer tended to ask the same question again or come up with their own explanation. Children notice a brush-off, and they keep pushing.
Guessing has a cost too. Koenig and Harris (2005) found that preschoolers trusted knowledgeable speakers over ignorant ones, and that 4-year-olds favoured speakers who had been accurate before over ones who had been wrong. A confident made-up answer that turns out to be wrong can cost you trust. Saying "I don't know, let's find out", and then finding out, keeps it.
The kind of answer matters as well. In Kurkul and Corriveau's 2018 study of 37 four-year-olds and their caregivers, children from lower- and middle-SES (socioeconomic status) families asked a similar share of questions, but middle-SES caregivers gave more explanations to causal questions, and more non-circular ones, than lower-SES caregivers. "It floats because it floats" is circular. "It floats because it pushes aside enough water to hold it up" is an explanation.
What should I say when I can't answer a science question?
Here is a four-step script you can adapt for children of most ages:
Say the question back. "So you want to know why the outside of the glass gets wet when the water is inside?"
Be honest and invite them in. "I don't know. Let's find out together."
Ask for their guess first. "What do you think is happening?" Write their guess down exactly as they say it.
Agree on when. "Tonight after dinner we'll look it up." Then keep that promise. A "later" that never comes is a brush-off.
With teenagers, swap step 3 for "What would you search for?"
How do we search or ask together?
Go to sources in order and stop when you have an explanation that says why, not just what:
the child's own science textbook, which is pitched at their level
a museum, space agency or university website rather than a random video
their teacher, with the question written down so they remember to ask it
a quick test at home, if it can be done safely (our kitchen science experiments are a good place to start)
Check that two sources agree, and say the explanation back to each other in your own words. If neither of you can, you haven't found the answer yet.
For a teenager whose question touches a school topic, the Fermi Concept Library has a lesson for every concept in physics, chemistry, biology, mathematics and computing, so you can read the idea together. For ideas that are hard to picture, such as orbits or waves, the Fermi Simulation Lab has interactive simulations you can try side by side.
How do you turn hard questions into a family notebook?
Keep one notebook just for questions. A 2018 review in Developmental Review by Ronfard and colleagues splits question-asking into four parts: noticing that information is missing, phrasing the question, deciding whether to ask someone, and judging the answer and following up. A notebook gives your child practice at that last part.
Give each question one page:
the date, and the question in the child's own words
our guess
how we'll find out (book, website, person, test)
what we found, and where we found it
a new question it raised
A filled-in page might look like this:
Question (Meera, 8): Why does the steel tumbler sweat?
Our guess: Water leaks through the steel.
Test: Dry the outside, fill one tumbler with cold water and one with warm water, and wait five minutes.
Found: Only the cold one got wet. The textbook says water vapour in the air turns back into liquid on a cold surface, so the drops come from the air, not through the steel.
New question: Does it sweat more in the monsoon?
Each answer leads to the next question. When a page grows into a project, this guide to doing a science project from a good question shows how to turn it into a fair test.
Tonight, when the next question comes, start with the words you might be avoiding: "I don't know. Let's find out."
