Ask HN: Seeking ideas for preschool/school projects

Water bottle rockets that have to carry and land an egg without cracking it are fun, and the launcher except pump can be 3d printed. The kids can make the rest of the rockets out of cardboard/foam/plastic bag parachutes etc).

What's fun, and very interesting for both children and adults, is going zero tech. In fact, go back to prehistory.

You start with the different properties of stones. If you have flint, obsidian, granite, quartzite, gypsum, and calcite in your region -- find them together. If not, buy them. Teach your kids about their different properties, and how they were used to make hand tools.

Then, the different properties of woods. Hard, soft, green, etc. Show them why ash and hickory (and especially negatively buoyant cornus mas, if you can get it,) make much better tools than pine. Make wooden spears and harden their points in a fire you make with stone tools.

Then integrate the two -- use stone tools to make other stone tools, and combine stone and wood into wooden-handled stone tools. Make bows and stone-tipped arrows, and use them. Go foraging with the children, and teach them how to cook vegetables, fish, and meat over an open fire. (Note: Beware mushrooms unless you really know what you're doing.)

In short order, the children will understand how men have lived for hundreds of thousands of years. Then they can advance into copper smelting, pottery, building carts and canoes, making nets from natural fibers, writing on clay tablets, and so forth...

I feel that, as with math where the optimal method is to start with Euclid and then progress through the ages, one ought to learn to be in the world by moving through man's stages of development. At 4-7, they're in their prime for traipsing around the woods and making stone tools.

You could look into setting up a Code Club.

https://codeclub.org/en/

And we have a tonne of resources at https://projects.raspberrypi.org/en

Playing around with teachable machine is also a tonne of fun for kids, and MIT have a platform called RAISE playground that has Scratch with teachable machine extensions

Catapults

This isn't quite the example list that you are looking for as the mentioned 'projects' in the following list were done at home, with a lot more timeframe allowed to discuss / work on them. My children are now 8 and 10, but we have been doing such similar things around the home since they were of similar ages to yours. A few of the things that we have done, and became large hits (hardly all computer related, but I think perhaps it's a mentality you are aiming for -- learn, create!)

* Augmented reality sandbox -- The software is still out there. You may have already seen these in action, but it really is not too terrible difficult to build a setup yourself. Old PC with some sort of GPU (for the rain effect, which is the coolest aspect..), a microsoft kinect, and a whatever quality projector. This went over super well in my living room when the kids were 4 & 6 -- And we recently re-built it 4 years later -- The 4 year old didn't even remember it, but I have lots of pictures of her loving it at 4!). Super cool, super interactive, and a good tie in of 'building things using old technology'.

* Grabbing weather from passing NOAA satellites! Build a simple di-pole antenna using whatever materials (we used copper pipe). Involves math and science discussions, and also may get the little ones interested in the weather. RTLSDR, some copper pipe, a laptop, some software, and knowing when to be tuning in. A good example of how 'the first time you try something it may not work as well as you'd like', tweak away from there. Pretty exciting to pull a picture from a satellite line by line. Listen to the signal -- Memories of dialup will immediately be there.

* Use a streaming camera and speed-cam software to create a setup to see 'how fast they can run'. Process and result and discussions about how this setup works can lead to fun insights.

* Stop motion video creation -- Probably the best for your use case, have kids use technology to create their own stop-motion videos. I remember doing this back around the ages of 7, but at that time it was frame by frame using construction paper and a giant VHS camera on a tripod. Techniques have not changed really, but the setup to do stop motion on small scale kid levels is basically free. Shows how iterative processes add up.

* Build a bubble making machine -- I imagine you may have a box of old computer fans, motors, etc, etc. Build a bubble machine! Have them try to design one out. 7 year olds likely able to really design rough concepts, 4 year old can help assemble and most importantly, spill the bubble liquid all over the place! If you want to get fancy, have it become a motion activated bubble machine using motion detection via some ESP32 setup or whatever. "This is what we are trying to do, these are the resources on hand, how do YOU think we could make this happen?".

String up a wire, bust out the RTLSDR (or other SDR stuff) and try to listen to some shortwave from around the world or your area. Pulling whatever from the air always seems basically magic to all kids (and honestly, it's pretty much magic to myself as well).

Not really an able to do at school thing, but son build an AM / FM radio kit that had your typical Chinese 'instructions' and was able with a tiny bit of help to solder everything to the board and have it work first try. As someone else mentioned, it went "Lots of interest > I'm kind of tired of this > I'm so close I will push on > Oh my goodness, the radio works, this is the best". I'm a huge fan of trying to install the 'keep at it' or make changes to make things better way of teaching and learning.

* School/Maybe -- * Make electromagnets by wrapping some wire around some good sized nails, put a switch on it, and both mentioned age groups will likely find it super cool and is certainly electronic/science based.

Just a few of the things we have done around my house thus far and have shown a lot of engagement and interest, and helped to create that 'spark' about wanting to learn more stuff.

I think this summer will bring more radio related things: Sensors to monitor humidity levels to be graphed from our garden, building some actual meshtastic nodes to chat to other people way across town over the airwaves, etc. My 10 year old has started designing a project to "automatically lower sunglasses over his glasses if it is sunny", and I hunch we will finally acquire a 3df printer to see this project through to completion. I'm hardly a programmer, but he did a '30 days lost in space' kit last year, and between the information he started poking with through that, and the assisting of some AI, I'm sure we can work together to pull his implementation off, however he goes about it.

As others said, it's great to see trying to share the desire to learn into the little ones -- They are way more capable than society lets on, you just have to get them interested in things and they are astounding tiny sponges! Good luck!