Here's an imaginative but simple & cheap kids project that fosters both creativity AND solar insights-ideal for 8-10 year olds! It's based around a ~$2 tube style solar garden lamp and blown out egg shell.
Step 1: Solar Easter Egg Lamp
The basic of the Instructable involves decorating a carefully emptied egg shell, then placing it over an up-ended solar garden lamp base. The effect in the dark is MAGICAL, & a suprising ammount of light is produced. It's ideal for kids bedside lamps, as parts & electrics are completely safe. The lamp's internal NiMH (Nickel Metal Hydrid) battery will run for several hours, and readily recharges when the solar cell is exposed to the sun.
Step 2: Solar Garden Lamps
Solar garden lamps abound in the US$2 range, but specials at times slash the price. Pre Easter 2013 New Zealand's "The Warehouse" chain were selling 4 for NZ$5 = ~ US$1 each. Yikes -the parts alone within are worth more than this, especially the rechargeable AAA NiMH battery.
The lamps come with well written instructions, and (if time allows) these should be carefully read through before starting the project.
Step 3: Safety Alert!
Alert: Most boys WILL promptly play "warriors" if issued the tubes & pointed ground probes! The ends are VERY sharp, so either trim them back or remove them from the issued materials entirely, otherwise accidents may occur...
To further stress this point check some "Room 3" kids at a rural New Zealand school who've just been issued the lamps. You can see at a glance that a LOT of stage mike/Olympic torches/decoration etc hi jinks may promptly result!
Step 5: Rain Gauge?
The clear lamp surround is just on 50mm (2") tall internally, & if supported on 2 tubes it'll make a handy rain gauge! ( A single tube may do but rain splashes from the nearby ground can bias readings). Note- a small drainage hole in the lamp surround will first need blocking with hot melt glue.
Step 6: What's Inside?
The lamp innards can be inspected by carefully undoing 2 small screws. If doing this however make some neat alignment marks before hand, and AVOID breaking any wires, as they'll need tedious resoldering! Inside you'll find an AAA rechargeable battery, the rear of the solar cell and a 1.2V to ~4Volt booster circuit. The workings of this are quite complicated - refer => https://www.instructables.com/file/F4MAL5MGSEEK0QH if interested.
Step 7: Eggs
But back at the Easter Egg lamp itself. Start by carefully tapping a small hole in the base of an egg with a spoon & remove the shell fragments.
Step 8: Blowing the Contents
Here's 8 year old Nicole showing Marie (her grandmother) how to suck eggs! Well - not quite - the idea is to use a bendy straw to gently blow out the egg's contents into a bowl. Perhaps also use the straw to stir the yolk & white inside so they're easier to empty.
Step 9: An Emptied Egg Shell
A close up of the result - bendy straws make this easy (although a little messy at times!) . For hygiene it may be best not to have humans cook & consume this, but instead just pass the egg contents to your appreciative cat or dog !
Step 10: Animal Feed?
Picky eater "Molly" showing her appreciation. However she's a fish fanatic and wouldn't -sigh- consider the egg & white until we cooked them & added some brewers yeast spinkles...
Step 11: Washing the Shell
Wash the emptied egg shell out under the tap so that it's clean- shake the water out & carefully dry the shell.
Step 12: Decoration
Once the shell is dried decoration can begin. All manner of effects can be made, with spirit based felt tip pen markings perhaps the easiest. However classic shell dyes with onion skins etc may have some mileage too. Keep in mind that the shell will be lit from within, so solid external effects & stickers etc will not show at night.
Google for inspiration, but appreciate that the likes of classic Russian eggs may take weeks to decorate.
Step 13: Switch Markings
The lamp's black switch can be hard to see against the base, so touch it up with a white correcting pen. Add a dot at the "ON" position too, so that moving the 2 dots together indicates it's switched on. (Do NOT put a white dot on the "OFF" position of course).
NOTE: Although it automatically lights up in the dark, the lamp will only charge in the sun if switched ON !
Step 14: Assembly Line!
Best make one for your brother while the assembly line is organised!
Step 15: Table Tennis Ball Version
Egg shells are cheap enough(!), but rather fragile unless reinforced with a polyurethane coating. For more rugged demands consider a punctured table tennis ball, as this makes a really durable cover.
Step 16: Other Covers
All manner of transluscent items can be placed over the LED, with a NZ "kina" sea egg shell particularly beautiful.
Note: Although the coloured tube lamps are visually eye catching, they cost slightly more & are less suited to this lamp. In the dark some light tends to bleed thru' the coloured plastic which rather weakens the appeal of the covered LED.
Step 17: Cape Gooseberry Mantle?
Everyday items abound that suit use as a lamp cover. Here's a dried Cape Gooseberry mantle that looks fantastic in the dark.
Step 18: Spooky !
A dried poppy seed head looked particularly spooky. ( The cord attached here was used to hang the lamp base up in a charging sweet spot. However it's not well hung this way, since the base leans too far downwards to capture higher angle sunshine)
Science meets art -$2 worth of DIY educational bedtime fun !
Step 20: Pendant Lamp Extension
Once the appeal of the Easter Egg Lamp has passed, perhaps consider a further enhancement of the solar base. This involves drilling a few holes to attach a cord & reposition the LED. Although more involved (& usually needing adult help), this makes a really popular SOLAR PENDANT - refer my further Instructable => https://www.instructables.com/id/Education-Solar-Garden-Lamp-based-pendant/