Skip main navigation

New lower prices! Get up to 50% off 1000s of courses. 

Explore courses

Clouds in a lab

Cloud in a bottle

In this video Pete demonstrates how changes in pressure result in cloud formation, using a demijohn bottle, a bicycle pump and ethanol.

Pete pumps air into the sealed jar, increasing the pressure to the point at which the rubber bung is ready to pop from the neck of the demijohn. When the rubber bung is removed, the pressure in the jar drops rapidly and the vapour in the jar condenses to form a cloud.

How do you think the state of the atmosphere in the room you are in – the temperature and humidity –might affect the cloud that forms? We look forward to hearing your thoughts in the Comments area within this Step.

This article is from the free online

Come Rain or Shine: Understanding the Weather

Created by
FutureLearn - Learning For Life

Reach your personal and professional goals

Unlock access to hundreds of expert online courses and degrees from top universities and educators to gain accredited qualifications and professional CV-building certificates.

Join over 18 million learners to launch, switch or build upon your career, all at your own pace, across a wide range of topic areas.

Start Learning now