Children learn the same way everyone does when they are completely free of others’ expectations and other interfering impediments to learning. They learn by wondering about something, thinking about it, finding out about it, perhaps reading about it or discussing it or looking it up on the internet, all driven by their own curiosity.
If neither option appeals to the child there are reasons for that. What are the reasons? There is a problem to solve. There will be something good that the child wants, and something bad that the child wants to avoid. We just need to find out what those things are, and start thinking laterally to come up with a solution that provides the good and not the bad.
Learning science could include conversations, reading, thinking. It might or might not include experiments. Experiments are tests of theories—so first you need a theory to test. Theoretical physicists do no experiments at all. They think. The same could be true of a child.