Information about Gravitational lensing demonstration with Fizzics Education | Kids Science Experiments

Gravitational lens demo

Gravitational lens demo

Follow FizzicsEd 150 Science Experiments:

You will need:

One wine glass

A surface with a speckled black background that simulates the night sky (we used a kitchen countertop)

Gravitational lens science experiment - materials needed

This science demonstration is so simple! Place the wine glass upright on a background that simulates the night sky. We used a kitchen counter top but you could also use a photo or poster of the night sky or even make an artwork with galaxies, nebulae and stars.

2 Gravitational lens science experiment - materials needed

While you watch the base of the wine glass stem, slowly move the glass around on the pretend night sky backdrop. Notice how the glass distorts the images of the patterns below the glass?


This distortion is not that much different from what occurs to starlight when a very heavy celestial object passes across the front of a distant star!

Science behind the experiment

The heavier the object, the more gravity it has. Very heavy objects such as black holes or clusters of objects such as galaxies can have a lot of gravity. When these heavy objects pass in front of a distant star, galaxy or nebulae, the light from those distant objects can be bent by the heavy object passing in front.

Why? Well, it turns out that gravity seems to be a consequence of space being warped by an object. The heavier object, the more the space surrounding the object gets warped. As light travels towards us from a distant object it can follow the bent space around the heavy object and as such the heavy object can act like a lens!

This effect means that astronomers can actually look around massive objects like galaxy clusters for the focal point of light coming from even further distant objects. Once that focal point is found you have effectively used the galaxy clusters itself as part of a giant cosmic telescope.

NB: more correctly; space & time are linked together so technically both space & time can get warped by heavy objects (called spacetime).

Gravitational lensing diagram by NASA. Image credit: NASA/JPL-Caltech

Learn more!

From sunspots and asteroids to black holes & supernovae, the Stars & Planets and the Earth, Sun & Moon workshops have your unit on space covered!
Get in touch with FizzicsEd to find out how we can work with your class.


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