Session 7

Teacher Tips

Hook

• It helps to let the uncertainty sit before you reveal the experiment. Learners will naturally split between “yes, chemicals can combine on their own” and “no, something else must have been needed”. Both instincts are reasonable, and that’s exactly the tension Miller and Urey set out to test.
• You might point to the words on the board (oceans, gases, volcanoes, lightning) during pair talk rather than asking the open question cold. It gives learners something concrete to reach for instead of guessing blindly.
• It’s worth not rushing past the reveal. Knowing that two real scientists actually built this in a flask in 1953 is what turns the hook from a thought experiment into something learners want the answer to.

ITZA Pathways

• On Pathway 1, it helps to ask “Why was energy needed to turn gases into amino acids?” in their own words. It’s easy to remember “lightning” as the answer without understanding what the lightning was actually doing.
• On Pathway 2, you could get learners to test MRS GREN on something in the room: the classroom plant or their own pencil case works well. Applying the framework to something real is what makes it stick, rather than just memorising the acronym.
• If a learner asks “Are viruses alive?”, it helps not to resolve it for them. It’s a genuinely open question in science, and it’s worth being honest about that uncertainty.
• “Which fact surprised you most?” is a good one to reach for with a learner who’s gone quiet. It works on either pathway.

Classroom Activity

• It helps to frame this properly before pairs start: they’re not deciding what’s alive, they’re auditing for the exact point where each item fails. That reframing is what stops the activity turning into a guessing game.
• Fire and icicles tend to catch people out, because they look like they’re doing something alive: moving, growing, consuming fuel. You might push learners to name exactly which MRS GREN boxes each item ticks and which it doesn’t, rather than accepting a general “sort of alive” answer.
• The seed is worth spending a moment on. It looks dead but passes all seven; it’s dormant, not lifeless. That’s often the biggest surprise in the room.
• Viruses will likely split the class, and that’s fine. It works to let pairs disagree and defend their verdict rather than pushing for one correct answer.

Plenary

• The reflective question asks whether today’s evidence challenged what learners assumed “alive” means. It helps to ask for a specific piece of evidence in their answer, not just “yes it did”. That’s what turns it into a real reflection rather than a one-word response.
• The lock-in is from Brian Cox, the physicist and broadcaster, in 2013. It says life isn’t a fluke but what physics and chemistry do when the conditions are right, which is the idea behind the Urey-Miller experiment. It’s short, so it works to read it just as it is, then ask “Does today’s evidence back him up?”