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Lasers And Balloons

Helps students to understand how they can be lights in the world and help overcome darkness.

by The Revd John Challis

Suitable for Key Stage 3


To help students to understand how they can be lights in the world and help overcome darkness.

Preparation and materials

  • You will need to have a laser pointer, as used to point to words or pictures during lectures – preferably a quite powerful green one.
  • You will need two black and two white balloons, with spares, a balloon pump or helium to inflate them and three balloon weights.
  • This assembly requires the curtains to be closed and lights dimmed (you may need to check that this will be OK ahead of the assembly). Note that the ambient light makes a difference to how well the practical demonstration works. You will be using the laser pointer to pop the black balloons, which tends to work better when there is some light. However, the room needs to be darker when you shine the laser pointer on the white balloon so it really glows dramatically. Take a little time to rehearse in the venue for the best results or arrange for the light in the room to be dim rather than fully blacked out.
  • Explain to teachers before the assembly and to the children on the day that some of the balloons will pop.
  • Blow up one black balloon and one white balloon and, if you want to extend the assembly and you are able to do this (it is tricky), roll one white balloon into a thin twist and place it inside a black balloon. Using the balloon pump to get it started or helium if you can, blow the white balloon up first, still inside the black balloon, then tie it off. Blow the outer black balloon up a little further, so the white balloon will pop down into the black balloon, floating inside it. Tie off the black balloon. You should now have two balloons in one. Attach a weight to it. You could add some confetti between the white and black balloon.
  • Blow up one single white and one single black balloon and attach each one to a weight.
  • Place the ‘three’ balloons (one black, one white, one black with a white one inside), attached to their weights, on a table in front of the students.


  1. Explain that Jesus said he is the light of the world so those who follow him will never walk in darkness. Talk about how, at Easter, Advent, Christmas, Candlemas and Lent (or even in relation to baptism), as is relevant to the season in which you are running the assembly, that we often think about how Jesus is the light who banishes darkness. Say that today you will demonstrate this, but, first, you must point out, you should never play with laser pointers – they are not toys and this demonstration will show why.

    Ask for the curtains to be closed and the lights dimmed.
  2. Ask the students to imagine that the light from the laser pointer is the light of Christ. The white balloon is like us people and the black balloon is the darkness in the world. Shine the laser pointer on the wall or ceiling so that the students can see the light and explain how you should never shine it in people’s faces. Standing over the black balloon or even, carefully avoiding people’s faces, pointing the laser at it from, for example, the back of the hall, moving it about a bit, show how the black balloon absorbs the light. It might also even shine right through it.

    Now direct the laser pointer at the white balloon. The white balloon will totally change colour and light up as the white colour bounces the light in every direction, filling the balloon as if it were a ball of bright light. It will shine beautifully and be quite surprising.
  3. Next, move the laser pointer so it points back to the black balloon, but, this time, keep the laser pointer as still as you can on one point (you will need to be reasonably close to the balloon). Say that the black balloon represents our darkness, the things that we have done wrong, and Jesus came to banish this darkness when we follow him. In the few seconds it takes you to say this, the laser will burst the balloon. Most of the students will be surprised, so be ready for that reaction. Explain that this is like Jesus banishing the darkness with his light.

    Now turn the laser pointer on the white balloon, which will not burst, but glow instead, and say that Jesus wants us to let his light come into us like this. He wants us to reflect his light and fill our lives with him.

    You could end there, but, if you can, it is better to continue as follows.
  4. If you have managed to create the balloon inside a balloon, recap, directing the laser pointer at it concentratedly, as before. This time, when the black balloon bursts, keep the laser pointer directed at it so it hits the white one inside, but then move the light around a little, and it will glow but not pop. It surprises the students and, if the balloon is filled with helium, it will rise and, because you are keeping the laser pointer on it, it will stay bright and reflect the light. If you have added confetti, when the black balloon bursts, it is very dramatic.

    Either way, you can add at this point that, by following Jesus and letting his light into our lives, he sets us free.
  5. You might conclude by giving some scientific information. You can explain that we tend to wear dark clothing in winter as, then, like the black balloon, we absorb the light and the heat and this keeps us warm. Similarly, we wear white in summer to reflect the light, which keeps us cool.

Time for reflection

We often talk about Jesus being the light of the world and the one who banishes darkness. When we ask Jesus into our lives, that is what he does. We must learn to be like the white balloon and reflect his light and his love.


Father, God,
Lighten our darkness and help us to reflect your light and truth.
You want us to be lights who bring light to others, so fill us this day with your light.


'Shine Jesus shine’ (Hymns Old and New (Kevin Mayhew), 479, 2008 edition)

Publication date: September 2013   (Vol.15 No.9)    Published by SPCK, London, UK.
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