Hi Ciara,
you make a point about ” removing the pressure of needing a ‘right’ answer, ” that I frequently make in teacher training sessions.
Nobody ever got a Nobel Prize for knowing the answer before they started!
I advise putting on an air of a slight befuddlement when carrying out investigations — tell the children that last time you did this activity with a class the weather was different / the class chose to use XX instead of YY and so YOU DON’T KNOW THE ANSWER. This means they aren’t trying to get the “right” / “teacher” answer.
With the jellies, the technique of getting fingerprints should be given to the children, they can then consider if they could improve the technique in some way and then go on to use the technique to tell them something new about fingerprints that they have predicted based on their understanding. It could be something simple like — does the size of a fingerprint depend on the size of the person (do tall people have big fingers?)….