Exploding Air!

 The difference in electrical charge between the bottom of a thundercloud and the ground may be more than 305 volts per foot (1,000 V/m), so a lightning spark releasing that potential has a huge amount of energy. Some of this heats the air through which the lightning flashes and makes the air explode. The sudden expansion of air, followed by its rush back into the partial vacuum it has created, sends shock waves in all directions. It is those shock waves the sound of the explosion that we hear as THUNDER!

You can make a similar explosion by popping a balloon or by flicking a


1) FOLD the two longest edges of the paper together.
Then open the paper out so that it is flat on the table again.

2) INDIVIDUALLY FOLD down each of the four corners to the first centre fold.
Make sure that they meet the centreline exactly.

3) FOLD the paper toward you along the centre fold
so that you enclose the flaps of the previous step
Do NOT damage the flaps.

4) FOLD the paper in half as shown so that the tips of the opposing sides meet.
Open out the paper again so the fold line shows.

5) BRING the two top corners down toward you so that they meet
and are parallel with the previous fold from Step 4.

6) FOLD the paper back on itself so that the two points face you.
This will make a triangle shape.
The banger is now ready to GO!

7) HOLD the two top corners together.
SWISH the banger down with a quick flick of the wrist.
A loud bang will occur as the air is compressed.

Printable Version

Return to Grade 3 Science

Return to Lightning (Grade 5)