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How can I teach Radiation and Radioactivity?

Discussion in 'Science' started by Cosmic_Rainbow, Mar 13, 2012.

  1. Cosmic_Rainbow

    Cosmic_Rainbow New commenter

    I just starting a topic all around radiation and radioactivity etc and would really appreciate some ideas on what activities i can get the children to do.

    Also as a student teacher i have been told i cant use the sources etc so can even demo it for the students
  2. Cosmic_Rainbow

    Cosmic_Rainbow New commenter

    I just starting a topic all around radiation and radioactivity etc and would really appreciate some ideas on what activities i can get the children to do.

    Also as a student teacher i have been told i cant use the sources etc so can even demo it for the students
  3. If you're not actually allowed to handle them yourself what about asking the technician f they could demo while you talk through them?
  4. steve_cooke

    steve_cooke New commenter

    Staticly charge a balloon, hang it up for a couple of hours, then very carefully deflate it and test it with a GM tube, you can get quite a good count and a half life from it - if I remember rightly it is accumulating dust as gaseous radioactive elements (radon) decay into solids.
    We have enough GM tubes for the kids to be able to show that LoSalt has a higher count than background - because of the K-40 in the potassium chloride, supposedly you can show the same thing with brazil nuts and bananas which both have high potassium contents but I've never done it. And gas mantles from the type of gas lamps you use when camping contain thorium.
    But just standing there with a counter clicking due to background is usually enough to get their attention.
  5. Presumably you are looking at GCSE? How good is your Physics knowledge of radioactivity and the associated topics? I don't want to teach granny to suck eggs, but without knowing what you know, it's hard to give advice.
    What does ionisation mean? Can you charge and discharge a gold leaf electroscope competently, whilst describing what is happening at the electron level? Have you seen the "splitting candle flame" experiment? Do you have a spark counter? Can you describe the action of a GM tube?
    Are you familiar with the properties of 3 types of radiation?
    Have you considered randomness by tossing coins / rolling dice? How would you display the results of the whole class? Can you access a computer simulation?
    Describing the alpha scattering experiment is often helped with a simulation.
    How can you consider the uses of radioactivity (smoke detector, paper thicknesser, medical investigation, etc)?
    Are nuclear equations on your spec? What about nuclear fusion and fission? Chain reactions (21st Century had a nice demo using lots of matches relating to critical mass)?
    Does your school have a scheme of work detailing their expectations and resources? It will make a good starting point.
    Good luck.
  6. A model of radioactive decay that the pupils can relate to is throwing dice. I advise you to test this out before hand, to ensure that you explain it clearly & set the results table up correctly (otherwise you end up confusing the pupils).
    Get 100 dice & share them around the pupils (or the pupils you can trust- at the front of the room as the 'demo' group). Draw up a table with 3 columns for 'No of dice left', 'After how many throws', Number of sixes thrown..
    The first row will have 100, 0 & a blank in it.
    Then get the pupils to throw the dice. Count & remove the dice that have landed on a '6'. Fill in the blank with the number of sixes thrown (eg 12).
    Then start the next row of the table with 88 (100 - 12) as the 'number of dice left', & 1 in the column of 'after how many throws'. Throw the dice again, count, remove the sixes & put the number of sixes thrown into the last cell of your table. Carry on........ and on....... until you get down to zero or one or two dice. Get the pupils to write the results in their books as you go through the experiment (helps to keep them on task & stops them messing with the dice). The throws have to be well managed or you risk losing track. The pupils will soon realise that they are running out of dice & there may be an incentive to cheat since they want to carry on throwing dice. Keep an eye open for this.
    Anyway, you will end up with a set of data that can be plotted (Y-axis = number of dice left, X-axis = number of throws). Then they can estimate the half life of the dice. This is also a good opportunity to get them more comfortable with drawing 'curve of best fit' rather than 'line of best fit' graphs.
    The last time I did this, I think we went up to 20 or so throws.
    You can use this model to explain the unpredictability of decay of any one atom (dice) and that once an antom has decayed it is no longer 'available' for further decay. Half life is also easy to explain - it is clear on their graphs.
    Hope this helps.
  7. An alternative which students love is to do the same as above but use skittle sweets. The kids shake the sweets on a tray and remove those with the 's' facing upwards. They then record the numbers of sweets left. The data is then plotted as above. If you use the same axis as that for the dice the decay curve is steeper illustrating the effect of a shorter 1/2 life. You only have a 1/2 life of one throw and as there is an average of 56 sweets in a small packet (aren't teachers sad!) you will find that the experiment only lasts about 6 throws. This is an ideal activity for a last lesson, you would not want to send the kids on to a colleague bombed out on 'e' numbers!

    Have fun, I like the orange ones the best!
  8. Why can't you use the sources? If local regulations state you need to be trained, cannot you be given some instruction. As a technician I am quite happy to give sources out for e.g. A2 investigations (where there is a suitable, sanctioned risk assessment).

  9. http://www.iop.org/education/teacher/resources/radioactivity/page_41558.html
  10. wkclark

    wkclark New commenter

    Got this from my B placement and did it today with my new Year 10 class! Went ok...
    Football, ping pong ball and light source. clamps stands. Set them up clamps stands along a surface to represent the different particles that the radiation can 'run into'. I set them up in two rows so that the football would just about squeeze through, but not quite, for paper, which stopped the football but not the ping pong ball. Closed the gap a bit so ping pong ball (beta) could get through but light still could. Had them completely together for lead, which created a shadow on the other side, indicating most gamma was stopped too!
    I explained that this was a model, like we had 'zoomed in' so we could see the individual particles. They couldnt really get why we couldn't see the actual particles though... C/D target group (attainment more like E). I had shown them the source though, so it was easy to relate that we hadn't seen alpha particles there and they seemed to get the idea. Good for more visual people...
  11. blazer

    blazer Star commenter

    Mulitmedia science school (software) has some useful stuff on range and penetration including a virtual expriemnt. It also has some stuff on half life.

    The Cambridge GCSE Physics books (about 15 years old now) have some brilliant diagrams and questions about background radiation and where it comes from.
  12. My old technician used to come in and demo. Pupils responded well to the novelty of it.
    Also, theres a simulation you can download called Radiation Lab, not sure if it costs.
    And PhET is worth a google for loads of simulations, bound to be something there about decay.
    Don't know if it's a bit too old now, but I did a lovely lesson where pupils had to work out what killed Aleksander Litvinenko. We did the demo with the sources, I had to labour the point a bit but most pupils got the idea that it must have been an alpha source because gamma and beta would pass through the body (to some extent) allowing it to be detected externally and also being less devastating (though I wouldn't be keen to swallow any radioactive source). Not top level science but good enough for a F-C group.
  13. Cosmic_Rainbow

    Cosmic_Rainbow New commenter

    hey guys thanks for all the ideas. [​IMG]
  14. so..... what did you decide to do & how did it go .... or how is it going?
  15. bogstandardcomp

    bogstandardcomp New commenter

    check out radioactivity on pHET, no problems with holding them
  16. At one point I used to cook popcorn to explain randomness of decay. Pupils used to enjoy 'predicting' when it would 'pop'.
  17. Radiation is more strictly called "ionising radiation". It breaks the neutral molecules into charged particles. This requires energy.
    If you project the "shadow" of a candle flame onto a wall, it rises vertically (more or less) upwards. If you place 2 metal plates, one either side of the candle, and attach them to a high voltage power supply, the shadow "splits" - you "see" that the air is being ionised into positive and negatively charged particles.
    A charged gold-leaf electroscope is discharged by placing a sealed source on it because the source ionises the air; do it in a vacuum and you will not discharge it. It is not the chrged particles being emitted which is important, but their effect on the molecules around them.
    Establishing the fact that the source is creating ions is an important first step.
  18. twotime

    twotime New commenter

  19. I've just uploaded a resource about the radioactive boy scout. If you don't know the story, it's about a very resourceful American teenager who managed to acquire radioactive materials like americium (from smoke detectors) and thorium (from the mantles of gas lamps). He then tried to make a model breeder reactor in his shed, but was caught by the police. It's a fascinating story that should engage the students. The resource includes the story and two questions. One is to define the words in bold and the other is to edit the story down to the length of a newspaper article. So it's a bit of cross-curricular with English really. It worked well with my students, most of whom are ESL.
    I also tried to make a cloud chamber from a butchered smoke alarm, a petri dish, isopropyl alcohol and some dry ice, but I couldn't get it to work, which I was quite gutted about. The "how to" film I saw on Youtube looked really simple and very impressive. Maybe you could have a go at that.
    I realise that this is a bit out of time from your original post, but maybe next time it could be of use.

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