This site uses cookies. By continuing to use this site you agree to our use of cookies. To find out more, see our Privacy and Cookies policy.
Skip to the content

Share this

Free weekly newswire

Sign up to receive all our latest news direct to your inbox.

Physics on film

100 Second Science Your scientific questions answered simply by specialists in less than 100 seconds.

Watch now

Bright Recruits

At all stages of your career – whether you're an undergraduate, graduate, researcher or industry professional – can help find the job for you.

Find your perfect job

Physics connect

Are you looking for a supplier? Physics Connect lists thousands of scientific companies, businesses, non-profit organizations, institutions and experts worldwide.

Start your search today


Sandpit physics


By James Dacey

When you think of cutting-edge experimental physics, you might picture the grandiose detectors of the Large Hadron Collider (LHC), or perhaps a lab-coat-wearing scientist hunched over a shiny new microscope. Sometimes, however, all you need is a bucket of sand, a balloon and a pin.

That is what we discovered on a recent trip to a physics lab at the Benemérita Universidad Autónoma de Puebla (BUAP) in Mexico. Researcher Felipe Pacheco Vázquez treated us to a quick demo of how craters form as a result of an explosion in a pressurized air cavity in a sand bed. These holes in the ground have different characteristics from the craters caused by something big from space smashing into the Earth.

See the video above to see Pacheco Vázquez give a quick demonstration of the process to Physics World editor Matin Durrani. Those of you interested in learning how to handle sharp objects in a safe fashion would be advised to give the video a skip!

This week, Pacheco Vázquez and his colleagues have published a report of their research in Physical Review Letters. Their findings could help to identify the origin of planetary craters and to understand the evolution of planetary terrains. To be fair, the experiments described in this published study require a bit more equipment – including a high-speed camera, a hosepipe and an air gun. Nothing excessively fancy though.

Matin and I were in Mexico on a fact-finding mission for a special report on the country, which will be available on this website in September.

This entry was posted in General and tagged , , . Bookmark the permalink.
View all posts by this author  | View this author's profile


  1. M. Asghar

    It is normal that the explosion of a cavity under an “appropriate pressure” will lead to a crater. We often see huge and quite deep craters after the explosion of a bomb even at the surface of the ground.

    • Felipe

      Yes, something interesting is that the crater is always circular independently of the cavity shape if the cavity is located deep enough inside the sand. You can try with rectangular, trinagular, square-shaped, you always get a circular rim if a critical depth is considered.

      • M. Asgahr

        The crater is always circular, because of the outwards isotropic(spherically symmetric) high pressure exerted by the the explosion point.


  • Comments should be relevant to the article and not be used to promote your own work, products or services.
  • Please keep your comments brief (we recommend a maximum of 250 words).
  • We reserve the right to remove excessively long, inappropriate or offensive entries.

Show/hide formatting guidelines

Tag Description Example Output
<a> Hyperlink <a href="">google</a> google
<abbr> Abbreviation <abbr title="World Health Organisation" >WHO</abbr> WHO
<acronym> Acronym <acronym title="as soon as possible">ASAP</acronym> ASAP
<b> Bold <b>Some text</b> Some text
<blockquote> Quoted from another source <blockquote cite="">IOP</blockquote>
<cite> Cite <cite>Diagram 1</cite> Diagram 1
<del> Deleted text From this line<del datetime="2012-12-17"> this text was deleted</del> From this line this text was deleted
<em> Emphasized text In this line<em> this text was emphasised</em> In this line this text was emphasised
<i> Italic <i>Some text</i> Some text
<q> Quotation WWF goal is to build a future <q cite="">
where people live in harmony with nature and animals</q>
WWF goal is to build a future
where people live in harmony with nature and animals
<strike> Strike text <strike>Some text</strike> Some text
<strong> Stronger emphasis of text <strong>Some text</strong> Some text