### National Flags

This problem explores the shapes and symmetries in some national flags.

### Observing the Sun and the Moon

How does the time of dawn and dusk vary? What about the Moon, how does that change from night to night? Is the Sun always the same? Gather data to help you explore these questions.

### Troublesome Triangles

Many natural systems appear to be in equilibrium until suddenly a critical point is reached, setting up a mudslide or an avalanche or an earthquake. In this project, students will use a simple simulation game to investigate the properties of such systems.

# Spot Thirteen

##### Age 7 to 11 Challenge Level:

On the grid below, choose $13$ spots by clicking on them.

You will see that as you click more spots, your score changes.

Can you work out how the scoring system works?  We would love to hear what you did in order to test out your ideas.

Which spots should you choose to produce the maximum possible score?  How do you know that this is the maximum?

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