Counting a Seaweed’s Floats

This seaweed grows one new gas-filled float every year, so its floats line up in a row along the flat strap. Count the floats and you know how many years the seaweed has been growing.

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Every lesson is open to everyone for 7 days after it is published. This one came out on September 10, 2026: its text stays readable here, and its picture opens with a subscription.

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Age 9: open this week

In the picture

The widest float, at the base of the frond
The smallest float, near the tip of the frond
The split-open float in the puddle, letting out bubbles

Examples

Counting the rings inside a cut tree trunk to find its age
Counting the candles on a birthday cake to see how old someone is

Key takeaways

One new float grows on the frond each year
The number of floats is the seaweed’s age in years

Carry on in the app

Three questions on this lesson. It has left the free week, so its quiz is for subscribers.

At least one new illustrated lesson every weekday for your child’s year, with its quiz and a reminder at 6:15 pm.

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