Start STEM early! This is a great introduction to circuits for kids. It’s cheap and lots of fun! You will need :
A peg
A 3V button battery
Two LEDs (these cost around 20p)
Two sticky pads or some tape
One 0.09 metal guitar string (one string can make 2-3 bugs bots and costs around £1).

Slide the battery between the contacts of the LEDs. These only work one way round so flip them round if they don’t light. This is the simplest circuit to show your child.
Sticky pad them in place and bend two of the contacts up as in the picture above.
Bend a length of guitar string into a V to make two antennae. We’ve put tape on the cut ends for safety. The tape also catches the breeze making the antennae move!

Place your antennae on the battery and sticky pad them in place to form a sandwich.
Bend your antennae towards your LED contacts and when they are close form little hooks out of the LED contacts.

Now it’s time for your peg!

Add your legs, wings or whatever. You can fiddle around with the positioning of your wires so the Blinky Bug eyes are off until the antennae move, or easier for young children is that they are on until moved! One LED can last a couple of weeks continuously with one of these batteries. So no need to panic that they will run the battery down too quickly.
Wiggle to start the fun!