So gf has a 7 year old and I reactivated a glow stick last week ( hydrogen peroxide ) kid was amazed. Asked if I knew any more cool science stuff.
To today I did vinegar and baking soda in a jar with a straw taking the carbon dioxide and funneling through a hollow pasta noodle . Light noodle  on fire, start co2 generation. The co2 extinguishes the fire.

The second phase was baking yeast and hydrogen peroxide to make oxygen and basically a blowtorch through the same pasta noodle.

But I’m out of ideas for next week. My ONLY idea isn’t ideal because it isn’t as controllable . I was going to make tinfoil match stick rockets.

Any other ideas?

Only thing I got involves a erupting volcano and his big sister's friends.
Details are a bit sketchy.

Bio battery using lemons. Safe and simple

Aluminum foil and wooden match rockets?

Dry ice is cheap and fun.

https://www.crunchlabs.com/products/build-box-subscription

How about plain old electricity and magnets?

Ring a doorbell, light a light, make an electromagnet, show permanent magnets repel and attract, send a permanent magnet flying when energize an electromagnet, make gross chemicals and hydrogen gas from a salt water mixture, etch or plate some metals, make cool patterns (and a mess) with iron filings, etc.

Grow some crystals of salt or sugar.

Make up a batch of Black Powder.

Take a book of paper matches, trim off heads ( only the heads) then make a foil tube pinch and roll about 5-6 layers thick so the tube is tight. Pinch off front end, back end make pin prick in one end so that is “ back” . Put the “” back suspended over edge of table gold lighter under the pinhole and you get a ticket ; solid fuel , about 6-7 feet max.

red cabbage pH indicator

You could make a foxhole radio.  It's a simple radio that needs no power source.
https://www.survivalkit.com/blog/how-to-build-a-foxhole-radio/

I've always wanted to build a cloud chamber.  It allows you to "see" radiation.
https://m.youtube.com/watch?v=5lgSNzzDB0Y

How about food coloring and some celery sticks?

My daughter's favorite was a section on heat transfer and state changes, culminating in making ice cream in a bag while shaking it jumping around to Harry Belafonte's 'Jump in the Line'.

You're in ME.

1) Have you shown him the throwing a cup of cold water vs throwing a cup of hot water in cold air trick, yet?

2) Fun with ice:
a) Mpemba effect. Hot water freezes faster than cold water. Fill 2 ice cube trays, one with hot water, another with cold water. Stick them in the freezer.
b) supercooling water/instant freeze.
https://www.wikihow.com/Freeze-Water-Instantly
(actually seen this in person with the case of bottled water I kept in the SUV. Grabbed one to take a drink, it had been sitting overnight in below freezing. It was water when I grabbed it. As I twisted the cap, the bottle squished as I was holding it, and the plastic 'crackled' which initiated the freezing. Watched the whole bottle freeze in just over a second. Cool... wait. Crap... still thirsty, and I have a solid bottle of ice lol.

3) If you have adequate PPE, you could potentially teach him about the dangers of superheated water from a microwave and the danger of explosive boilover.

4) all sorts of cool experiments with magnets

5) heat transfer; you can boil water in a paper/plastic cup. As long as the material conducts heat to the water (i.e. not thermal insulating like styrofoam), and the flame is small enough (candle/Bunsen burner etc.), the heat is transferred to the water without the paper/plastic burning through. (Do this in the sink/outside in case you make a mess).


*** if a buddy of mine knew of this heat transfer experiment, he wouldn't have a scar on his arm. Some smart-ass, knowing that he was both stubborn AND had a high pain tolerance, told him that if he could use his lit cigarette to burn a hole through a $100 bill, he could keep the bill. He then stretched the bill tightly over my buddy's forearm.

Buddy was stubborn and dumb enough to 'tough it out' and ignore the pain. Never did burn through the note,  but has a permanent round scar on his forearm.

I was today years old when I learned that we have a homeschooling/parenting forum.

Tag for more ideas; my kids will love em.

Make rock candy with him. Not only does he get to check on his experiment daily to see his crystals grow, he also gets a treat when it done. https://www.thespruceeats.com/rock-candy-521016

I’d start with some basic electronics that you then build into robotics and programming. That way there is never an end.

Astro photography can be done easily without much investment and is another mind blower. Cheap telescope and old dslrs are cheap these days. It’s another thing you can continue to build upon.  

Here are a couple I have done with the kids when they were little.

Drop a neodenium magnet down a copper pipe - Lenz's Law




Electrolysis of water.




I still want to build a cloud chamber. Just have a hard time finding dry ice around here.

Use water to determine the density of objects.  Move up to irregular shaped objects and get their volume and density. You need a way to measure water volume either by a graduated container or collecting and weighing the runoff.

You can also make a chunk of ice, float that in a container almost full and let it melt and compare the water level. This shows H2O changes density when it freezes or melts.

Then take an old tall plastic glass and freeze it to break it to show the strength of water freezing.

Dissolve salt in distilled water and look at the resistance using a battery, wire, and light bulb or a multi-meter. Change the viscosity and look at the meniscus on a full container. (Soap does a good job of changing viscosity.)

Water is actually a very interesting substance and it's unique properties allow life to do what it does.

Supersaturatation. Kids love seeing crystals form

Or potatoes.

So will his dentist.

I always liked the boiled egg on the glass bottle trick.

Find a bottle that has an opening slightly smaller than the egg.
Heat the bottle with hot water.  Pour the water out and place the egg on the opening.
Watch as the vacuum created by the cooling air in the bottle sucks the egg in.

All I got is a bottle implosion. Elevation change from 9,400feet to sea level.

By my eye it’s about half the volume.

Bottle Altitude by FredMan, on Flickr

Sealed here

Position-Altitude 20170220 by FredMan, on Flickr

IMG_0629-Mauna Kea East View by FredMan, on Flickr

And carried to here

Sunset 20170221 by FredMan, on Flickr

Buy a cheap Geiger counter and some uranium glass.

Google "elephant toothpaste".  It is a favorite chemical reaction with kids...

Try putting a egg in a glass of vinegar.  The result is pretty cool.

So far ive done the following (basically 30 min max on these)

have him make and power up a Heros engine ( can of soda water poke two holes in it at opposite sides and direct the holes couter clockwise and empty out 90% of hte soda. then hold over a jet boil flame via piece of string on the top, it gets going pretty fast but it is unbalanced so it wobbles.

Crush soda cans with changes in atmospheric pressure. (empty soda can with open top, boil table spoon of water in it, then flip and imerse the upside down one in ice water, it NICELY crunches.)

Pasta rocket(h2o2 and yeast reaction pushed through a peice of penne pasta that is on fire.



plan for next weeks is tin foil/match head rockets,

then im thinking ill do a water in pie plate upside down drinking glass and candle that floats , make vaccum in the glass. BUT im thinking ill see if i can get the glass to have a ring of yeast aroudn the inside and use H2O2 instead of water. get a 2 part reaction. first the candle makes vaccume then the H2O2 reacts with yeast on inside of the glass and kicks it back out, then back up when it runs out

https://www.scientificsonline.com  perhaps?

Pocket laser pointed at a small piece of mirror glued to a speaker "cone". Speak into the microphone and "see" your voice as the laser squiggles all over the wall.

5gallon water cooler jug, 1/4 cup rubbing or denatured alcohol, shake around until distributed, pour out the excess, and hold a match/ lighter over the end, it will blast out a flame and you can watch the flame front propagate in the jug.