Pulsars

Introduction
Public summary: 

An experiment to introduce children to pulsars, explain what they are and how they can be used as clocks and to find out about the interstellar medium.

Useful information
Kit List: 

Pulsar Model
Sheet of translucent material (I think a sheet of paper may work)

Packing Away: 

Wrap up the model in tissue paper to prevent damage to the paintwork while it's in the box

Explanation
Explanation: 

Pulsar Experiment/Demonstration

1) Get out model pulsar, preferably in a dark/dim place. Turn on the fairy lights and spin the model around so that the kids get the idea that you can only see the light/emitted radiation when the beam is pointed towards them. Explain that this is because the axis of rotation is different to the axis along which the radiation is emitted.
2) Explain that these stars spin very fast because they are the remnants of much larger stars that exploded. These larger stars were spinning much more slowly but, after the explosion, they because much smaller. Hence, to conserve angular momentum, the rate at which they spin had to go up. Make comparison to ice skater/ point at spinny chair if that’s out as well.
3) Give them some numbers – the range of pulsars’ periods is from 1.4 milliseconds to 8.51 seconds with a typical period being around 1 second. Try and impress upon them how fast this is for a star to be rotating. Earth takes a whole day, so that's 86400 times faster!
4) Tell them how some kinds of pulsars have such reliable periods that they can be used as clocks. Demonstrate how this would work by using the model.
5) Get out the screen of translucent material. Ask one of the kids to hold it between the star and the audience and then ask the audience what they notice about the pulses from the star. Hopefully they’ll say that the pulses are less bright. Explain how this means that pulsars can be used to examine the properties of the media that lie between the pulsar and Earth.

Other talking points:
Explain what a neutron star is/ how one forms. Talk about how all the space between the atoms has been squeezed out and that one teaspoon of neutron star would weigh the same as a mountain.

Risk Assessment
Date risk assesment last checked: 
Sun, 02/02/2020
Risk assesment checked by: 
lucyhart.042
Date risk assesment double checked: 
Mon, 03/02/2020
Risk assesment double-checked by: 
Beatrix Huissoon
Risk Assessment: 

Use a model pulsar to explain to children about these fascinating objects and their uses

Hazard Risk Person(s) Affected Likelihood Severity Overall Mitigation Likelihood Severity Overall
Fairy lights inside the model Fairy lights inside model could heat up- potential fire risk All 3 3 9 Turn off fairy lights when model not in use.
In the event of a burn call first aider. In the event of fire, follow procedures in venue RA.
2 3 6
Spinning model Could accidentally hit a child with the model while spinning it. Public 4 3 12 Carry out demonstration at a safe distance from the children.
Call a first aider in the event of an emergency.
2 3 6
Bright lights Risk of dazzling if child looks directly into the lights Public 2 3 6 Tell children not to look straight into the lights. The fairy lights are very dim so this shouldn't be a big problem. 1 3 3
0
This experiment is sometimes run in a darkroom, see separate risk assessment.
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