Experimental MumScience + Children = Fun + Mess

This is one of  our favourite experiments, the kids like the farty noise and the dog likes the leftovers!

If you feel the need to re-create your own fart in a jar, here’s what you’ll need.

What You Need:

• An adult helper, to handle the hot water
• A strong glass bottle (we used a Tesco value brown sauce bottle)
• Some boiled eggs with shell removed
• A bowl containing a little bit of water
• Kettle of hot water

What To Do:

• Shell the boiled egg and leave it sitting in the bowl of water until required
• Carefully pour the hot water into the bottle and leave it to heat the bottle for a few minutes
• Carefully pour the hot water out of the bottle
• Quickly place the egg (pointy end down) over the opening of the bottle
• In a couple of minutes the egg should land in the bottle with a PLOP!

What’s Going On:

Before you start the experiment, the air pressure is the same inside the bottle and outside it.

You heat up the bottle with the hot water and when you pour the water out, warm air fills the empty bottle.

As the bottle cools, so the air inside cools. The cold air now in the bottle cannot provide the same pressure, but no new air can enter the bottle because the egg is in the way.

The air pressure outside the bottle is now greater than the air pressure inside it. The air above pushes down on the bottle and is stronger than the air inside. The egg – as it’s in the way – gets pushed down too causing it to drop in.

Once the egg is through the neck, air rushes into the bottle to equalise the pressure.