Day 14: Rocks and Minerals – The Earth’s crust
Preparatory Stage (Grades 3–5) Science | Apex Institute of Maths and Sciences
Welcome, Young Explorer! Today, our mission takes us deep right under our feet. The Earth is covered by a solid outer puzzle skin called the crust. Everything on this crust is made of rocks! But what are rocks made of? Tiny, natural building blocks called minerals!
Think of a rock as a delicious cookie, and minerals as the chocolate chips, sugar, and flour inside it. A rock can have one or many different minerals packed together tightly.
| Type of Rock | How It Is Formed | Cool Examples |
|---|---|---|
| Igneous Rock | Born from fiery liquid lava or magma that cools down and hardens. | Basalt, Pumice (it floats!) |
| Sedimentary Rock | Layers of sand, mud, and shells squeezed together over millions of years. | Sandstone, Limestone |
| Metamorphic Rock | Old rocks changed completely by intense heat and heavy pressure deep underground. | Marble, Slate |
Geologists (scientists who study rocks) don’t just guess what a mineral is—they use special superpower testing tools! Here are the master tricks to identify any mineral sample:
- Streak: Rubbing a mineral on a porcelain tile to see the true color of its powder form.
- Luster: Observing how shiny it is under light (Is it metallic like gold, or dull like clay?).
- Cleavage: Checking if the mineral splits smoothly along flat lines when tapped cleanly.
When you sketch or write with a classic yellow pencil, you aren’t using lead at all! You are scratching a shiny, slippery mineral called Graphite across your notebook paper. Its weak mineral bonds let it slide off easily onto your sheet!
Look around grand kitchens or beautiful monuments like the Taj Mahal! They use Marble (a metamorphic rock) and Granite (an igneous rock) because they are extremely tough, durable, and polish up beautifully to shine under home lights.
Go outside into your garden or a local park with your parents. Pick up 3 distinct looking rocks. Use an old iron nail or coin to try scratching them. Check which rock is toughest, write down their textures, and draw their colorful patterns in your science diary!
Ask a parent to show you common kitchen table salt. Examine the tiny grains closely using a magnifying glass or a phone camera zoom. You will discover they are neat, tiny translucent cubes! Table salt is actually a mineral mineralogists name Halite.
Defeat all 10 questions to conquer the Earth’s Crust Challenge! Select your choices carefully.
