SCI02 · ScienceReels

Light comes from light sources. Some light sources are natural — made by nature. Others are artificial — built by people. Can you tell which is which?

Natural light sources make light without human help. The sun is our most important natural light source — it lights up the day. Fire is natural. Fireflies glow naturally too!

Artificial light sources are built by people. They usually use electricity. Examples: flashlight, lamp, candle, streetlight. These help us see at night and in dark places!

Remember: Natural = made by nature (sun, fire, firefly). Artificial = made by people (lamp, flashlight, streetlight). The moon is not a light source — it only reflects sunlight!

Light travels in a straight line. When a solid object gets in the way, the light cannot go through. The dark area on the other side is the shadow. The shadow is always on the opposite side from the light.

The size of a shadow can change! When the sun is low (morning/evening), shadows are long. When the sun is high (midday), shadows are short. Moving closer to a light makes the shadow bigger.

Sound is caused by vibrations — objects moving back and forth. When a drum is hit, the drum skin vibrates. Those vibrations travel through the air to your ears. When vibrations stop, sound stops.

Pitch is how high or low a sound is. Fast vibrations = high pitch (squeak!). Slow vibrations = low pitch (boom!). Volume is how loud or soft a sound is. Big vibration = loud. Small vibration = soft.