Finn’s been asking to do another “exbebibent” and Ioan wanted to design another dinosaur tray, so we combined the two. I also used it as an opportunity to record in a tally.


  • Packets of dehydrated water beads
  • Measuring spoons
  • Large bowls
  • Pouring devices filled with water (watering can, jug, measuring cups)
  • Whiteboard and pens


Step 1: They discussed what they wanted their dinosaur tray to look like and selected the colour of water beads they would need for each element. Ioan chose blue and purple for the water, alongside both dark and light green for the grass. Finn chose orange, pink and red for his volcano.

Step 2: They predicted what size measuring spoon they would need for one packet of dehydrated water beads.

Finn selected pink 1/4 teaspoon first, but realised it was too small. Ioan went next and decided to try the blue teaspoon, because it needed to be bigger.

Finn decided to try the red tablespoon, which was too big. Ioan tried to tell him that he thought he should try the blue like him, but Finn went with red. I was happy for him to learn for himself through trial and error.

He commented, “I am just like Goldilocks!”

Step 3: Once they had worked out which size spoon to use for each packet, I asked the how they could keep track of the number of spoons they put in. Ioan suggested writing it down and Finn was happy because he said he was very good at writing numbers!

They sounded out the words and wrote them themselves.

Ioan is very supportive of Finn’s early attempts at writing and often asks Finn to help him spell his own words.

Step 4: I asked if there was a problem with writing the numbers. Ioan said, “You would have to write 1, and cross it out, then 2 cross it out..”

I demonstrated how to represent numbers with tally marks. I explained that tally marks can record frequencies or occurrences (how often or how many) when making observations.

This was their understanding of tally marks:

In our experiment our tally marks would represent the number of teaspoons of water beads.

Step 5: We added water using a watering can, jug and measuring cups.

We staggered the start time, by adding water to the different bowls at 5 minute intervals. Starting with the ‘volcano’ beads, then the ‘grass’ and finally the ‘water’. This meant we could observe the difference as the beads hydrated over time.

The fastest changes were in the first half hour (first two pictures), where the differences between the bead size in the three bowls was greatest. You can see the difference between the second and third pictures, taken an hour and a half apart, wasn’t as large.

Step 6: After a few hours the water beads were fully hydrated and they were very excited!

They predicted how many blue teaspoonfuls of hydrated water beads there would be, then measured them out and kept track by recording with tally marks on their whiteboards.

After a few teaspoons, Ioan realised his prediction of 19 teaspoons was way off and that it was going to take a long time to count them all. He said he wished they could use tablespoons instead. I said he could, if he could figure out what one tablespoon of water beads was equivalent to in tea spoons.

Once we got to 59, every ten (60, 70, 80 etc.) Finn was convinced it would be 100! This was a chance for Ioan to help Finn with his numbers.

When it was Finn’s turn to count the volcano beads, we had chance to embed some of the higher numbers he had just learnt.

Step 7: Convert the number of tablespoons back in to teaspoons.

No. tablespoons of beads x 4 = No. teaspoons of beads.

Blue: 82 x 4 = 328 tsp.

Green: At the start of the experiment, we had the same number of green water beads as blue, so estimated there would be 328 teaspoons of green too.

Red and Orange: 149 x 4 = 596 tsp.

Afterwards, we used our water beads for a dinosaur tray and some sensory play.

DfES Early Learning Goals (2017)

Communication and language

ELG 02 – Understanding:

Children follow instructions involving several ideas or actions. They answer ‘how’ and ‘why’ questions about their experiences and in response to stories or events.

ELG 03 – Speaking:

Children express themselves effectively, showing awareness of listeners’ needs. They use past, present and future forms accurately when talking about events that have happened or are to happen in the future. They develop their own narratives and explanations by connecting ideas or events.

Physical development

ELG 04 – Moving and handling:

Children show good control and co-ordination in large and small movements. They handle equipment and tools effectively, including pencils for writing.


ELG 10 – Writing:

Children use their phonic knowledge to write words in ways which match their spoken sounds.


ELG 11 – Numbers:

Children count reliably with numbers from 1 to 20, place them in order and say which number is one more or one less than a given number. They solve problems, including doubling, halving and sharing.

ELG12 – Shape, space and measures:

Children use everyday language to talk about size, capacity and time to compare quantities and to solve problems. They recognise, create and describe patterns. They explore characteristics of everyday objects and shapes and use mathematical language to describe them.