Teaching students about the earth's various layers can be an easy task when students are science-oriented. But it can be downright daunting when students portray a limited interest in learning geology. In an effort to keep things exciting, hands-on experiments can work wonders at heightening a student's curiosity. Experiments can be very scientific and quite precise, or they can be more creative and very fun.
Create a worksheet to utilise the scientific method. Use three liquid substances (water, vegetable oil, and pancake syrup), and have students determine their positioning if layered like the earth's crust. Ask which has more density. The concept of density might need to be defined; density is the mass of a substance's ratio to its volume. Gather students' predictions and put the liquids to the test by pouring them into a clear-glass container. The liquids layer themselves according to their density; the syrup will be on the bottom, the water in the centre, and the vegetable oil on top. Students can brainstorm as to why the earth's layers are situated as they are. Explain how the earth's core consists of the most dense materials, while the crust is composed of less dense particles, which rest upon the mantle. From here, you can go into depth regarding the actual composition of each layer.
Make an edible earth to demonstrate its layers. Place one spice drop into a marshmallow. The spice drop comprises the inner core of the earth, while the marshmallow represents the outer core. Cover the spice drop completely and set aside. Create the earth's mantle by combining 1 tbsp of butter with 12 more marshmallows; melt in a microwave for 1 minute. Mix thoroughly with 2 cups of rice cereal and let cool. With moistened hands, roll the cereal, or earth's mantle, around the core and pack it tightly into a ball. Freeze for 15 minutes prior to covering with a bottle of chocolate shell. Once hardened, cut open, observe and eat. This simple and fun experiment can lead to a more complex discussion of what the layers are physically comprised.
Apples for Earth
Use an apple to depict the earth's layers. Cut the needed number of apples into quarters, from top to bottom, and give a slice to each student. Explain that the skin of the apple is much like the earth's crust; it's very thin compared to the other layers. The meat of the apple portrays the earth's mantle, which makes up the majority of the earth and is made of molten rock, very similar to hot asphalt. The apple's core resembles that of the earth's core, which has two distinct compartments: one inner, one outer. Following this demonstration, have students draw a model of the earth, labelling the crust, mantle, outer core and inner core.
The earth can be created with a variety of foods and other products. A hard-boiled egg is a fine example of the earth's core, mantle and crust; a half-cut cantaloupe provides a similar example. Making a pizza with the toppings placed in concentric rings is a fun cooking/science activity that can be utilised to illustrate the earth's layers. Earth-balls created from various colours of clay or play-doh can nicely represent the different layers of the earth. Rhythm Rhyme Results, an online educational-rap site, offers a fun song for learning about the earth's layers.