Three children, child A, Sarah and Salla are sitting and chatting on the steps in front of a house. Suddenly, a strange sound came out.

Child A: What is that noise?

Sarah: Oh yes

Then Salla ran to the place where the noise was made, followed by child A and Sarah.

When they reached the place, the children saw a woman using a lawnmower, and a sound came from it.

Child A is blocking her ear with two index fingers and says: "it is making much fracas."

Salla: I think it hit a little part here

Child A: Wait, I heard something

It is the sound like music or from an instrument. The three children listened to that sound.

Sarah: Ah, my music ...

Moreover, the three children dance to the music.

Then the children decided to walk to hear more distant sounds.

Sarah: I heard the sound of the air conditioner

Salla: point your finger forward and say, "I heard the sound comes from over there

Then everyone decided to move in that direction, and Salla noticed where the sound was coming from.

Child A: "The sounds like wind, a little."

They started moving to another place.

Salla continued pointing towards the direction of the sound and said: "I heard cars from high way down below that fence"

Sarah: "It is really loud here."

Salla: "The sound likes a bunch of motors going at top speed, speed í really fast."

The children walk over the bridge while using their hands to cover their ears.

Sarah sat by the lake and closed her eyes so she could hear more sounds.

Sarah: "I heard something like a low horn thingy, it í kind like from over there" while pointing in the direction of the sound.

The three children then used various objects to touch the wire mesh fence to make different sounds.

It seemed that the three children enjoyed discovering the different sounds around them. It can be seen in the anecdotal observation record that three children ran over to find out what the sound was. Child A, Sarah and Salla also have basic knowledge of sounds to compare similarities and differences between sounds. According to Piaget: "children learn by active way and teacher is not centred. In Piaget's theory, the teacher is a mentor to help them develop their knowledge based on their certain knowledge. Cognitive development happens in stage". It means that children actively learn and explore the world based on existing knowledge, and teachers will be the ones to help children develop that knowledge. We also see this in the anecdotal observation. The children actively explore the sound world around them by deciding to go to different places for comparison. Children are always curious about everything around them. It also means that children are eager to learn and explore the world around them, so teachers and caregivers need to care for and support them—the child's comprehensive development. Children are curious about the different sounds they hear from their surroundings and get quite excited about them. They locate the sound and run to find out what the sound is. Identifying where the sound is coming from and comparing it with sounds it has heard before is like comparing sounds coming from an air conditioner that sounds like wind. It proves that preschool children can develop memorization of information, establish a comparison between old information and newly received information.