Pumice Boat

ACES Challenge Entry

Bayanaka Adyastha Kusuma Putra

SDN 1 Mangkujayan



The Pumice Boat is a raft boat that floats with the help of buoyancy as a counterweight. The boat benefits from the pumice’s unique characteristics. Pumice is a type of rock formed by volcano lava. The two volcanoes nearest to Ponorogo Regency in Indonesia are the Kelud and Merapi mountains. Kelud’s eruption in 2014 distributed volcanic ash to west through Kab. Ponorogo and into Yogyakarta Province. It’s not surprising that many volcanic rocks are found in Java island.

There are a lot of volcanic rocks scattered all over the island of Java, therefor this activity uses the natural volcanic material within an educational game to form a novel learning activity. This simple experiment will introduce children to the different types of stones in a fun way, keeping them from getting bored. This experiment makes use of basic materials found locally and a method of play that can instruct children by having them interact directly with the objects, making this activity suitable to be played by children aged 6 and above. Children as young as six years old are expected to make their own Pumice Boat. The basic principles of sinking, floating, and electricity in utilizing a glue gun are considered to be comprehensible by children as young as six years old.

Learning and Competency Outcomes

Aside from having fun with the game, children are expected to engage with learning by getting to know the stones’ special characteristics. As STEM learning, this activity uses a simple technology of utilizing pumice as a counterweight for a simple raft. This activity demonstrates aspects of engineering through the assembly of the Pumice Boat. An understanding of the science behind floating and sinking is gained through buoyancy experiments using various rocks found across Indonesia. Coral stone, garden stone, decorative stone, and pumice stone are some of the stones that were used. Children can exercise mathematics skills by sorting stones that can be used to create a Pumice Boat using Mathematical Logic Concepts.

Playful Aspects

This activity is a playful learning activity because it is delivered through games and direct observation of the object being studied. Children can directly carry out the experiment on the stones that have been provided and test which stones can make the boat float. This direct implementation will increase children’s curiosity and create a playful atmosphere when they finally find the right type of stone to float the boat. In addition, children will find this game a playful activity when it is conducted in a group or competitive situation. Children may find more fun through cooperation and the desire to excel in a competitive environment.

Frugal Aspects

The Pumice Boat activity uses frugal materials and tools. This is because the primary component of pumice boats is a naturally occurring substance in Indonesia, particularly in the Ponorogo Regency. The materials used are twigs, pumice stone, red plastic, miniature human figure, and wax glue. While the tools used are scissors, and a glue gun. These objects are easy to find in the local environment and available school resources.