Why is my shadow long in the evening?
At noon it hides under your feet. By six o'clock it stretches halfway across the terrace. Your child has not grown in six hours.
A shadow is not something you make. It is a patch of ground that your body is stopping light from reaching — a hole in the light, shaped like you.
When the sun is high, light comes down steeply and the patch it cannot reach is small. When the sun is low, the light arrives almost sideways, and the patch stretches a long way. Same child, same height, different angle.
Try it today
Stand a stick upright on the terrace and chalk the tip of its shadow every hour. By evening you have a curve of marks, shortest around midday. That row of chalk marks is a sundial, and your child built it.
One honest note: the noon shadow gets shortest, but it does not vanish. Only in a narrow band of India, on one day of the year, is the sun exactly overhead.
The word for it: angle — the direction light arrives from.
Why can't I see around a corner?
You can hear your mother in the next room. You cannot see her. Both travel to you — so why does only one manage the corner?
Light goes in straight lines and will not bend around a wall. If there is no straight path from a thing to your eye, you cannot see it.
That single fact explains a great deal at once: why a shadow has the shape of the object making it, why you can block a torch beam with your hand, and why a keyhole shows you only a narrow slice of a room. Sound spreads and spills round corners. Light does not.
Try it today
After dark, shine a torch down a corridor and ask your child to stand where the light cannot reach — round the corner. Then ask them to call out. They can be heard but not seen, and they will work out why before you finish explaining.
The word for it: light travels in straight lines.
Does a mirror really swap left and right?
Everyone says it does. Raise your right hand and the reflection raises its left. It seems settled — and it is wrong.
A mirror reverses front and back, not left and right. Your nose points away from you; your reflection's nose points towards you. That is the axis that flips.
It feels like a left-right swap because to imagine facing the other way, you picture yourself turning sideways. The mirror does not turn you sideways. It turns you inside out, front to back.
Try it today
Write your child's name on paper and hold it up to a mirror. It reads backwards. Now hold the paper facing the mirror and read it from behind, through the paper — it reads backwards there too, with no mirror involved. The mirror did not do anything the paper could not.
This one is genuinely hard, and it is fine to leave your child unconvinced. Saying "I find this confusing too" is a better lesson than a tidy answer nobody believes.
The word for it: reflection — light bouncing off a surface at the same angle it arrived.
Common questions
›Why is my shadow long in the evening and short at noon?
Because the sun is at a different height in the sky, and your shadow is simply the patch of ground your body is blocking light from reaching. When the sun is high overhead around midday, the light comes down steeply and the blocked patch is small — a short shadow gathered at your feet. In the evening the sun is low, the light arrives almost sideways, and the blocked patch stretches far across the ground. You have not changed size. The angle of the light has changed.
›Why can I not see around a corner?
Because light travels in straight lines and cannot bend around the wall to reach your eyes. This is also why shadows have the shape of the thing making them — the light that misses the edges carries straight on, and the light that hits the object stops there. Sound is different, which is why you can hear someone around a corner but not see them. That contrast is worth pointing out; it surprises most children.
›Does a mirror swap left and right?
No, though almost everyone says so. A mirror reverses front and back, not left and right. Your reflection's nose points towards you while your nose points away — that is the axis that flips. It looks like a left-right swap because when you imagine yourself turning around to face the other way, you turn sideways. Writing looks reversed for the same reason. If you hold up a page and read it in a mirror, the letters have not been swapped left to right so much as turned to face the other way.
›How do I explain a shadow to a very young child?
Do not explain it first. Play with it. Make hand shapes on a wall with a torch held still, move your hand closer to the torch and watch the shadow grow, then move it back towards the wall and watch it shrink. A three-year-old does not need the word "blocked" to notice that closer to the light makes it bigger. The explanation lands much better later, once the noticing is already there.
Build the sundial properly
The stick-and-chalk idea above is a whole afternoon's activity if you give it room — and it ends with a child who can tell the time from a shadow.
Shadow clock on the terrace →