Why did your Dragon Potion turn into Dragon Snot?

At first, your Dragon Potion could flow almost like an ordinary liquid.

But hidden inside it was sodium alginate, a natural substance made from brown seaweed.

When the Dragon Potion touched the Dragon Pool, the sodium alginate met calcium ions in the solution.

The calcium began connecting the long alginate molecules together.

Instead of staying runny, the liquid changed into a soft, stretchy gel — Dragon Snot!

What is sodium alginate?

Sodium alginate is a natural material that comes from brown seaweed.

Its molecules are extremely long, so sodium alginate belongs to a group of materials called polymers.

You can imagine these polymer molecules as lots of tiny flexible chains mixed throughout the liquid.

While the chains can move past one another, the Dragon Potion can still flow.

What happens when alginate meets calcium?

The Dragon Pool contains calcium ions.

When the alginate chains meet calcium, the calcium begins joining different chains together.

These connections are called cross-links.

You can imagine the calcium acting like tiny bridges connecting one long alginate chain to another.

Why does the liquid turn into a gel?

As more cross-links form, the alginate chains become connected into a network.

This network traps lots of water inside it.

The water has not disappeared, but it can no longer flow as freely.

That is why the runny Dragon Potion changes into a soft, slippery gel.

This process is called cross-linking.

Did you make a new material?

Your Dragon Snot behaved very differently from the liquid you started with.

It could wobble, stretch and hold its shape.

The colour and flavour may have stayed the same, but the material now had very different properties.

Scientists describe properties as things such as how stretchy, strong, soft, hard or absorbent a material is.

By observing these changes, you collected evidence that changing how molecules are connected can change how a material behaves.

Do scientists really use alginate?

Yes!

Alginate is used in much more than Dragon Snot.

Because it can form soft gels and hold water, scientists use alginate in areas including food, medicine and medical dressings.

Scientists and engineers can change the ingredients and conditions to create gels with different properties.

Curiosity Spark

What do you think would happen if you:

• used more or less sodium alginate?

• used more or less calcium?

• left the Dragon Snot in the Dragon Pool for longer?

• changed the size of the drops?

Each change could affect how firm, stretchy or squishy your Dragon Snot becomes.

So here's your next mystery:

Can you change ONE variable to create the stretchiest Dragon Snot possible?

Try These Next

Crack the Mystery Goo – Investigate another strange material and discover why it can behave like a liquid one moment and a solid the next.

Super Absorber Challenge – Explore another amazing polymer and investigate how it can trap huge amounts of water.