Light helps us see the world around us. When sunlight or lamp light shines on a toy, the light bounces from the toy to our eyes. In the dark, there is little or no light to help our eyes see objects clearly.
Learning about light and dark helps young scientists understand day, night, shadows, and safe ways to look around.
Understanding Early Learners: Light and Dark
Not every bright thing makes its own light. The Sun makes light. A torch makes light when its battery gives energy to the bulb.
A candle flame makes light as the wax burns. Some things only reflect light. The Moon can look bright at night, but it does not make sunlight.
Sunlight reaches the Moon, then some of it travels toward Earth. A shiny spoon, a mirror, and a white wall can reflect a lot of light. A dark jumper reflects less light, so it may be harder to see in a dim room.
Light usually travels in straight lines. This helps explain why a beam from a torch can make a bright patch on a wall. Put a hand in the beam and the bright patch changes shape.
Your hand stops some of the light from reaching the wall. The darker area behind the hand is a shadow. Shadows can be long or short.
When a light is low, such as the Sun near sunset, a shadow can stretch far across the ground. When a light is high overhead, the shadow is often shorter.
A lamp close to an object can make a large shadow. Moving the lamp farther away can make the shadow smaller.
Different materials treat light in different ways. Clear glass lets most light pass through, so you can see through a window. This is called transparent.
Thin paper or a frosted bathroom window lets some light through, but details look blurry. This is called translucent. Cardboard, wood, and a closed book do not let light pass through.
These are opaque. Opaque objects make the clearest shadows because they block the light well. Students can test these ideas by shining a torch at safe objects and watching what happens on the other side.
Your eyes need time to work in a darker place. When you enter a cinema or switch off a bedroom light, things may seem almost invisible at first. After a short time, your eyes become better at using the small amount of light available.
This is why it helps to walk slowly in dim places. Bright light can be unsafe for eyes. Never stare at the Sun, even through sunglasses.
Never shine a laser or a strong torch into someone’s face. At home, notice where light comes from in the morning, during a car journey, or before bed.
Notice reflections in puddles and windows. Notice how a night light makes nearby objects easier to find while places farther away stay dim.
Key Facts
- Light helps us see objects.
- Sun, lamps, and fire are sources of light.
- Dark means there is little or no light.
- Light source + object + eyes = seeing.
- A shadow forms when an object blocks light.
- More light makes objects easier to see.
Vocabulary
- Light
- Light is something that helps our eyes see objects.
- Dark
- Dark is what we notice when there is little or no light.
- Light source
- A light source is something that gives off its own light.
- Shadow
- A shadow is a dark shape made when an object blocks light.
- Reflect
- Reflect means to bounce light off a surface.
Common Mistakes to Avoid
- Thinking our eyes make light is wrong because eyes need light from somewhere else to see objects.
- Calling every bright object a light source is wrong because some objects only reflect light and do not make their own light.
- Thinking darkness is a thing that moves into a room is wrong because darkness is the absence of enough light.
- Looking closely at bright lights is unsafe because very strong light can hurt eyes.
Practice Questions
- 1 Mia sorts 8 picture cards. Sun, lamp, candle, and flashlight give light. Rock, shoe, ball, and book do not give light. How many cards show light sources?
- 2 A room has 3 lamps. One lamp is turned off. How many lamps are still giving light?
- 3 A child can see a red toy in a sunny room but not in a very dark closet. Explain why the toy is easier to see in the sunny room.