■ Science 10 · Term 1 · Week 2

Ten Minutes at Home: Why the Ground Shakes Here

Nothing to buy. Ten minutes with two sheets of paper and two books. Your child is learning what happens where two of the Earth's plates meet — and why this country has so many volcanoes and earthquakes. This activity gives them the two pictures the whole topic rests on.

The activity: paper and books

minutes: 10 Materials: two sheets of paper and two books with hard covers. A table.

Lay the two sheets of paper flat on the table, edge touching edge.
Ask: <q>What happens if I push them together?</q> Let them answer before you push.
Push them together slowly. The paper buckles upward into a ridge.
Say: <q>That is how the highest mountains on Earth were made. Nothing went down — both sides went up.</q>
Now lay one sheet of paper flat and put a book on top of one end.
Push the paper toward the book. It slides underneath.
Ask: <q>Which one went down, and why that one?</q>
Say: <q>The thinner, heavier one. That is what happens where the sea floor meets land, and it is what makes volcanoes.</q>

Three things to avoid

What usually happens	Instead
Saying the plates <q>float on liquid magma</q>.	They do not, and this is the exact idea the week is fighting. The layer underneath is solid rock that flows very slowly, the way glacier ice flows without melting. Your child is assessed on this.
Saying that all plates crashing together make trenches.	Two continents colliding make mountains and no trench at all — that is what the first half of the activity shows. Knowing when there is <b>no</b> trench is worth more marks than knowing when there is one.
Answering the questions yourself when they hesitate.	Count silently to ten first. Steps 2 and 7 are the whole value of the activity, and handing over the answer removes it.

Three signs it is working

They ask <q>what kind of crust?</q> before saying what forms.
They object when somebody says the plates float on magma.
They can say why the Himalayas have no volcanoes.

If you only do one part, do the second one — <b>the paper sliding under the book</b>. That single picture explains trenches, volcanoes and deep earthquakes at once, and it is the picture most learners never actually see made.