Waves at Boundaries (CHaOS+)

Introduction
A few demos of transmission/reflection of waves at boundaries
Useful information
Kit List: 

Oven shelf
Oil and pyrex experiment (+ maybe lenses)
Wave machine (requires tape, skewers, and small masses [e.g. jelly babies, plasticine balls])

Packing Away: 

Put in its own box inside Oil and Pyrex

Frequency of use: 
1
Explanation
Explanation: 

A few demos on the effects that boundaries have on propagating waves, the general theme being 'waves cross boundaries easily if the properties on either side match'. This demonstration is kept in its own box inside Oil and Pyrex, because that is what it will most commonly be used alongside.

Wave machine:
Good for going over wave basics. Make by stretching gaffer between two tables, and evenly space skewers along it (it helps to mark the skewers' midpoints in advance). Stick another layer of tape on the top to secure the skewers, and put weights on their ends. You can play with skewer spacing and weight positions to vary the frequency and create boundaries. You should be able to reflect a wave of one of these boundaries, and the difference in wave speed should be noticeable. Note that the tape will stretch, and will need tightening every so often

The rest of the experiment is basically just Oil+Pyrex, and oven shelf.

Risk Assessment
Date risk assesment last checked: 
Mon, 07/01/2019
Risk assesment checked by: 
Josh Garfinkel
Date risk assesment double checked: 
Sun, 27/01/2019
Risk assesment double-checked by: 
Polly Hooton
Risk Assessment: 
Hazard Risk Likelihood Severity Overall Mitigation Likelihood Severity Overall
Skewers Ends of skewers could be sharp (could stab/cut people) 4 3 12 Don't set up in a high-traffic area (where people might walk through it), and make sure people don't lean in close. Ends of skewers have plastic on, so should be non-issue.
Call a first aider in the case of an injury.
1 1 1
Swallowing sweets/marshmallows Audience could try to eat them, which is unsanitary. 4 3 12 Keep an eye on children, and mention not to eat the sweets or Plasticine
In the event that something is eaten, warn parents/relevant adult to take the child to the GP if ill.
1 3 3
Oil and Pyrex Assorted risks due to Oil and Pyrex demonstration. - - - See separate RA for Oil and Pyrex.
Follow procedures in Oil and Pyrex.
- - -
Sounds from an Oven Shelf Assorted risks due to Sounds from an Oven Shelf - - - See separate RA for Sounds from an Oven Shelf.
Follow procedures in Sounds from an Oven Shelf.
- - -
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