DIY: Fish Trampoline | Tinkerer Box Blog

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Fish Trampoline

Stem Activities

Ages: 6-8

Less than 30 minutes

Grownup needed

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Have you ever seen fish bouncing on bubbles? Through this activity, children can observe water's 'invisible force' while learning about the scientific principle of surface tension.

Materials Needed

Plate
White paper
4 straws
Washing-up liquid
Marker pen
Scissors
300ml water
Ruler

A flat lay arrangement of craft supplies on a light woodgrain surface. The items include a light green plate with a blank white piece of paper on it, a bundle of colorful straws, a small beige bottle or tube, a clear glass of water, a pair of scissors, two white markers with blue and black tips, and a clear plastic ruler. The scene suggests the materials needed for a children's art or science project.

Step-by-step tutorial

Step 1

Squeeze 10 drops of washing-up liquid onto the plate.

A hand pours a clear liquid from a small, light beige, oval-shaped bottle onto a light green plate. The background is a light woodgrain surface. This suggests a step in a process, likely an art project or experiment, where the liquid is being prepared or measured before being mixed with other materials.

Step 2

Pour 300ml of water into the plate and mix the washing-up liquid and water thoroughly.

A hand pours water from a clear glass into a light green plate. The water is creating ripples in the plate. The background is a light woodgrain surface. This image likely depicts a step in a process, such as preparing for an art project or a science experiment.

Step 3

Take the straws and cut 6cm off the longer end of each using scissors.

Two hands are shown cutting colorful plastic straws on a light woodgrain surface. One hand holds a group of red, yellow, and light purple straws, while the other hand uses scissors to cut them. A black line indicates a measurement of 6cm, showing the length at which the straws are being cut. This image likely demonstrates a step in a craft project.

Step 4

Bend the cut straws as shown in the illustration.

Two hands hold a light pink bendy straw bent into an inverted V shape against a light woodgrain background. The bendable section of the straw is clearly visible at the peak of the V. This image likely demonstrates a step in a craft project where the straw is being prepared or shaped.

Step 5

Next, fold 0.5cm at one end of each straw and connect them together as shown.

Two hands manipulate colorful plastic straws against a light woodgrain background. One hand holds a purple straw, while the other hand inserts a small, red straw segment into the end of the purple one. This close-up image likely illustrates a step in a craft project involving connecting or joining the straws.

Step 6

Connect all four straws to form a square - this is your trampoline. Ask an adult for help if you find this step difficult.

Two hands hold a square frame made of connected, colorful plastic straws against a light woodgrain background. The straws are purple, pink, red, and yellow, creating a vibrant and playful look. This image likely demonstrates the result of a craft project.

Step 7

Draw your favourite fish on white paper using the marker pen, then cut it out with scissors.

On a piece of white paper placed on a light woodgrain table, a hand draws simple fish illustrations with a marker. There's a small yellow/orange fish, a smaller teal fish, and a larger blue fish being drawn. Another hand lightly holds the paper. The scene suggests a child or someone creating simple artwork.

Step 8

Place the paper fish in the soapy water, ensuring it's completely wet.

A small, yellow fish-shaped object floats in a shallow, light green dish filled with water. The dish rests on a light woodgrain surface. A few small bubbles are visible in the water. The image is simple and evokes a playful or childlike scene.

Step 9

Now, place the straw trampoline in the soapy water. Once it's wet, lift it out. Look carefully for the bubble film in the frame. Then place your fish on the bubble film.

Two hands manipulate a square frame made of connected, colorful plastic straws floating in a shallow, light green dish filled with water. The straws are purple, pink, yellow, and pale pink/white. A small, blue fish-shaped object floats inside the straw square. The dish sits on a light woodgrain table. The scene suggests a playful activity or a child's craft project.

Step 10

Gently move the trampoline up and down, and watch your fish bounce with the bubble! See how long you can keep your fish bouncing! If the bubbles pop too easily, try adding some sugar to the soapy water to make them more stable.

Two hands hold a square frame constructed from connected, colorful plastic straws. The frame floats on the surface of water in a pale green dish, which rests on a light woodgrain table. Inside the floating straw square are three small, colorful fish shapes. The straws are purple, pink, yellow, and pale pink/white. The fish are light blue, yellow/orange, and a smaller light blue. This image likely depicts a playful activity or a child's craft project.

The Science Behind It:

Water has surface tension, and washing-up liquid contains surfactants that break down the attraction between water molecules, reducing local surface tension. This tension difference causes water movement, which propels the paper fish. Additionally, the fish becomes coated with the soap solution, creating similar surface tension that helps maintain bubble stability and prevents popping.

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