The Start of the Universe

Teacher Tips

Hook

• It helps not to use the word “explosion” yourself when you set up the calendar. It is the image most learners already have, and once you have said it they tend to hold onto it. Describe it as space itself stretching, everywhere at once.
• Before you reveal when humans arrive, go back to the most extreme guess and ask whoever said June “Why did you pick June?” The jump to 11:52pm on 31 December means more when learners have something to measure it against.
• The bridge question usually pulls learners towards “we are tiny and insignificant”. That is worth hearing, but you could offer the other reading too. In the last few seconds of that year, the universe produced something able to work out how old it is.

ITZA Pathways

• Circulate with two specific things in mind rather than watching the room generally. Learners get stuck on the scale of the Milky Way in Pathway 1, and the Moon’s 1.3 second delay in Pathway 2 usually produces the best questions.
• A learner who finishes both pathways inside ten minutes may be skimming. You could check with one question they cannot answer from memory: “Why does a telescope show the past rather than the present?”
• You do not need everyone to finish. Progress saves, anyone who has worked through both pathways has enough to take part in the activity, and learners can pick up the rest at home.

Classroom Activity

• The difficult part is flipping the perspective. Learners have to imagine looking back at Earth from a distant object, rather than looking out from Earth. You might ask them to turn and face the back of the room and picture looking back at where they are sitting. That gets most of them there faster than any explanation.
• Someone may point out that you could never really see this room from Andromeda, and they are right, no telescope could. It’s worth explaining that the question is about when the light left, not whether anyone could make out the detail.
• When you reach Andromeda, it helps not to confirm the answer and move on. Anyone watching from there right now would see our ancestors making their first stone tools, and the light leaving Earth today will not reach them for another two and a half million years. That usually gets more reaction than anything else in the session.

Plenary

• Read the lock-in quote out and give learners five or ten seconds before you say anything else. It’s from Carl Sagan, the astronomer and science communicator who presented the TV series Cosmos, in 1980. If there is time, ask two or three of them what they made of it.
• Learners tend to write facts in Part 1 and then repeat one of them in Part 2. It’s worth saying out loud that Part 2 is asking what they think, not what they remember.