🦁
Kitimu says: "Did you know that a tortoise shell is shaped like a dome, but a turtle shell is flat and smooth for swimming? Today you're going to build all three types of shells and test which one floats best. Science and nature combined — let's go, Cub!"
🎒 What You Need
Sticks, leaves and mud
A basin or bucket of water
Stones or pebbles
Grass and bark
Clay (optional)
Your worksheet
📋 How To Do It
Build a tortoise shell: Create a high, dome-shaped shell using mud, clay, or packed leaves. Make it rounded on top like a helmet. Tortoises live on land, so their shells are built for protection — heavy and strong like armour.
Build a turtle shell: Now make a flat, streamlined shell using bark, flat leaves, or thin sticks. Keep it as smooth and flat as possible. Sea turtles need to glide through water, so their shells are designed to reduce drag.
Build a terrapin shell: Make a medium shell — not as domed as the tortoise, not as flat as the turtle. Terrapins live in freshwater and spend time both in water and on land, so their shell is a compromise between the two.
The float test: Gently place each shell on the water. Which one floats best? Which sinks? The flat turtle shell should float and glide, while the heavy tortoise dome may sink. Record your results!
The strength test: Place a small stone on top of each shell. Which one holds the most weight without collapsing? The dome shape of the tortoise shell should be strongest — just like a real arch in a building!
Ranger Tip: An easy way to remember: Tortoises live on land (T for Tortoise, T for Terrain), Turtles live in the sea (T for Turtles, T for Tides), and Terrapins live in fresh water (T for Terrapin, T for Tap water!).
Science connection: The dome shape is one of the strongest structures in nature. That's why tortoises have survived for over 200 million years — their shell design is practically indestructible!
📸
Take a photo of your three model shells and the float test, then share it in the Junior Rangers WhatsApp group!