To make a science video for kids, start with a question a child has actually asked ("why is the sky blue", "where does the rain go", "why do cats purr") and answer only that question, in two to three minutes. Write it as a conversation in short sentences, with one everyday comparison that carries the idea and one picture per step. Simplify, but never say anything that is false, because children remember the first explanation they hear for years. Check the science against a reliable source, keep it short enough that the child asks for it again rather than drifts off, and end with a small thing to try at home, so the video leads to looking at the world rather than to more screen.

Start with a real question

The best kids' science videos answer something a child has already wondered about. A video called "Light and the Atmosphere" is a lesson. A video called "Why is the sky blue?" is an answer, and a child who has asked that question will watch the whole thing to find out.

Keep a note on your phone of the questions your child asks. Within a fortnight you will have a list longer than you could ever film. Typical ones from four to eight-year-olds:

• Why is the sky blue?
• Where does the sun go at night?
• Why do we have to sleep?
• How do birds fly?
• Why does ice melt?
• Where does the water go when it rains?

Each of these is one video. Resist the urge to add the next question on the end. "And that is also why sunsets are red" is fine as a final teaser. A whole second explanation is a second video.

Simple, but never wrong

This is the rule that matters most, and it is harder than it sounds. A simplification leaves things out. A wrong explanation puts something false in. Children cannot tell the difference, so the adult has to.

The "wrong" column is not made up. These are the explanations many adults still believe, because someone told them as children. A short video is a chance to give a better first answer.

When you are not sure, check a children's science source from a museum, a space agency or a public broadcaster before you write the script. NASA's Space Place, for example, has a clear page on why the sky is blue. Then check what the drawings show, because a generated drawing can quietly contradict the narration: a sun going down behind a sleeping face, a sea mirrored in the sky.

A worked example: why the sky is blue

Here is a script for a four to seven-year-old, about 280 words, so just under two minutes at a gentle pace.

Look up on a sunny day. The sky is blue. But why? Why not green, or pink, or yellow?It starts with the sun. Sunlight looks white, but it is really made of all the colours mixed together. Red, orange, yellow, green, blue and violet. You can see them all in a rainbow, when raindrops split the sunlight apart.Now, between us and the sun there is air. Lots and lots of air. Air is made of tiny, tiny bits, far too small to see.When sunlight comes down through the air, it bumps into those tiny bits. Most of the red and yellow light goes straight past them, like a big ball rolling through long grass. But blue light gets bounced. It bounces off one tiny bit, then another, then another, all over the sky.So wherever you look in the sky, blue light is bouncing towards your eyes from every direction. And that is why the whole sky looks blue.What about violet? Violet light bounces even more than blue. But the sun sends us less violet, and our eyes are not as good at seeing it. So the sky looks blue to us.And here is something to think about. At sunset, the sunlight has to travel through much more air to reach you, sideways across the land. By the time it gets to you, most of the blue has been bounced away. What colours do you think are left?Tonight, look at the sunset and see if you were right.

This is Rayleigh scattering, without the name. Nothing in it is false. "Tiny bits" is what molecules are, at this age. "Bounced" is a fair word for scattered. The violet paragraph answers the question a sharp seven-year-old will ask, and the sunset is a question rather than an answer, so the child does the last step themselves.

Scenes

Scene 4 is the one that carries the explanation. Check it carefully: the red light must go straight and the blue must bounce. If the drawing has them the other way round, or shows every colour bouncing, redraw it. The narration and the picture must say the same thing.

Make it

1. 1

   Pick one question your child asked

   Write it as the title, word for word, in the child's own phrasing.

2. 2

   Find the simple right answer

   Check a museum, space agency or public broadcaster's children's page. Write the answer in two sentences a five-year-old would understand.

3. 3

   Write the script

   Short sentences, one everyday comparison, one step per paragraph. Keep it to 200 to 400 words, which is two to three minutes.

4. 4

   Paste it in and keep your wording

   In openCanviz, paste the script, choose Keep my wording, and pick a friendly style such as doodle on paper or whiteboard, where the drawing builds as you explain.

5. 5

   Check that each drawing says what the words say

   Go scene by scene. Redraw anything that contradicts the narration, even slightly. Fix it in that scene alone.

6. 6

   End with something to try

   Finish on a question or a small experiment the child can do away from the screen, and do it together afterwards.

How long, and how often

Young children's attention for a single explanation is short. As a working rule, aim for two to three minutes for four to seven-year-olds and up to five minutes for eight to ten-year-olds. A child who asks to watch it again has understood it better than one who sat through ten minutes.

Screen time matters too. The World Health Organization recommends no more than one hour of sedentary screen time a day for children aged two to four, and less is better; the American Academy of Pediatrics gives similar guidance for two to five-year-olds and recommends that parents watch with them. A home-made science video is a good use of a few of those minutes, especially watched together, with you pausing to ask "what do you think happens next?"

The most useful thing a science video can do for a small child is send them away from the screen.

Something to try afterwards

For the sky video, there is a classic kitchen demonstration. Fill a tall clear glass with water and stir in a few drops of milk. In a dark room, shine a torch through the side of the glass. From the side, the water looks faintly blue. Look through the glass towards the torch from the far end and the light looks yellow to orange. The milk particles are doing what the air does, on a small scale. The effect is subtle, so add milk a drop at a time until you see it.

Every science video should end with something like this: a thing to look for, make, or test. Then the video is the start of the science, not all of it.

If your child is older and making a video of their own for school, the guide on science explainer videos for class covers the four shapes of a school science concept. For the general method of showing a process step by step, see how to explain a process in a video.

Common questions

What age is this for? The approach works from about four, when children start asking why, to about ten. Below four, a short spoken rhyme or a picture-book style story usually works better than an explanation; see making a nursery rhyme video.

Should I use the scientific word? Once, at the end, if the child is seven or older. "Scientists call this scattering." Children enjoy knowing the real word, but it should label an idea they already understand, not replace it.

Can my child narrate it? Yes, and children often love hearing themselves. Record them reading the script one scene at a time, and use their recording in place of the generated voice. Each scene's recording sets its own timing, so a slow reader is fine.

How do I know the drawings are scientifically right? Compare each drawing with the narration line it goes with. If the words say blue light bounces, the picture must show blue light bouncing. Most errors in generated science drawings are of that kind: the picture is plausible but says something slightly different.