The Earth is composed of four layers: the crust, the mantle, the outer core and the inner core. Models of the layers of the Earth must contain these four components. You can make an edible model of the Earth using a watermelon, an orange and a banana. Simply cut the fruit and arrange it to represent the Earth's layers. You should make this perishable model shortly before presenting it, or else keep it covered and refrigerated so the fruit stays fresh.
Use the knife to cut the small seedless watermelon in half widthways. Use the melon baller to scoop out the middle of one of the watermelon halves. Hollow out a round section that is big enough to snugly hold the orange.
Cut the orange in half widthways. Place one of the halves into the hollowed middle of the watermelon.
Peel the banana and cut it in half. Then cut a thin slice from one of the halves to make a disc. Insert the toothpick into the middle of the orange half, then push the banana disc onto the toothpick so it lies flat, and centred, on the orange. Press the toothpick into the fruit so it does not stick up.
Make a key to explain the parts of your fruit model using the paper and pen. The watermelon rind is the Earth's crust. The watermelon's flesh is the mantle. The orange is the outer core. The banana at the centre is the inner core.