When the lights in the movie theater dim and cell phones are muted, the movie is about to begin. In the dark, you can hear an occasional cough or the rustle of candy wrappers and smell the aroma of buttered popcorn. The screen begins to reflect light. Welcome to the world according to Hollywood, a world of make-believe made from moving images and digital sound.
When you get hungry, you grab a snack from your fridge or pantry. But what can plants do when they get hungry? You are probably aware that plants need sunlight, water, and a home (like soil) to grow, but where do they get their food? They make it themselves!
Plants are called autotrophs because they can use energy from light to synthesize, or make, their own food source. Many people believe they are “feeding” a plant when they put it in soil, water it, or place it outside in the Sun, but none of these things are considered food. Rather, plants use sunlight, water, and the gases in the air to make glucose, which is a form of sugar that plants need to survive. This process is called photosynthesis and is performed by all plants, algae, and even some microorganisms. To perform photosynthesis, plants need three things: carbon dioxide, water, and sunlight.
By taking in water (H2O) through the roots, carbon dioxide (CO2) from the air, and light energy from the Sun, plants can perform photosynthesis to make glucose (sugars) and oxygen (O2). CREDIT: mapichai/Shutterstock.com
A thunderstorm is a disturbance in the atmosphere that is characterized by lightning and thunder. Lightning is an electrical discharge in the air generated by charged particles in moving air masses. Because lightning is a phenomenon of moving, charged particles, not rain, we see lightning in violent forest fires and volcanoes as well as thunderstorms. Thunder is the sound produced by the shock wave lightning generates. The air immediately around lightning is suddenly heated to high temperatures—up to 30,000°C (54,000°F)—and subjected to high pressure; it expands rapidly.
Have you ever heard someone say, “Clouds are just water vapor”? Next time, you’ll be able to correct them.
While it’s true that clouds contain water, they actually aren’t made of water vapor. If they were, you wouldn’t be able to see them. The water that makes up clouds is in liquid or ice form. The air around us is partially made up of invisible water vapor. It’s only when that water vapor cools and condenses into liquid water droplets or solid ice crystals that visible clouds form.