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Thread: Help and Ideas needed.

  1. #1 Help and Ideas needed. 
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    Hello

    I'm a 16 year old student in search of a subject for an essay. The idea is that we start from a question and transform this into an experiment. Normally this wouldn't be a problem but I just can't think of anything that is impressing enough yet doable with our limited resources. Therefor if you have ever done something or now something which I could use I would be very grateful. Every idea is more than welcome.

    Greeting
    Gwen
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  2. #2  
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    Quote Originally Posted by Gwen View Post
    Hello

    I'm a 16 year old student in search of a subject for an essay. The idea is that we start from a question and transform this into an experiment. Normally this wouldn't be a problem but I just can't think of anything that is impressing enough yet doable with our limited resources. Therefor if you have ever done something or now something which I could use I would be very grateful. Every idea is more than welcome.

    Greeting
    Gwen

    Hello Gwen , Welcome to the forum. I had some ideal. How about explosion? Normally explosion is quite impressive.
    You can start some question about explosion : it's speed , power,... ANFO is quite powerful and it is properly the most cheapest and easiest-to-make explosion. All you need is fuel , NH4NO3(which you can buy from fertilizer store) and a Blender to mix all. You can just look in google for information to make ANFO
    If this doesn't work . Why don't you tell me about your facilities? And perhaps I will come up with something
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  3. #3  
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    I would stick to something simple e.g how is the time it takes to melt an ice-cube related to its size. Explosives may cause damage!
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  4. #4  
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    Quote Originally Posted by Gwen View Post
    Hello

    I'm a 16 year old student in search of a subject for an essay. The idea is that we start from a question and transform this into an experiment. Normally this wouldn't be a problem but I just can't think of anything that is impressing enough yet doable with our limited resources. Therefor if you have ever done something or now something which I could use I would be very grateful. Every idea is more than welcome.

    Greeting
    Gwen
    Typically I don't like doing students homework for them but with just the initial idea in this case I guess it's okay.

    Get a large block of wood and a rather large metal plate such as large frying pan. Let them both come to room temperature. Take someone from the audience and ask them to put one hand on the metal plate and the wooden block and then tell you which is warmer. Tell them to take their hands off now. Then take a cardboard stand and put "Warmer" in front of it and "Cooler" in front of the other so you and the audience can remember which is which. Then take two ice cubes, as identical as can be, and tell the audience that you're going to put an ice cube on top of each. Ask them which one will completely melt the fastest. Then put the ice cubes down on top of them and watch. It'll take about 15 minutes (You might want to do this on a video and record it and then play it in class).

    Which one do you think will feel colder? Which ice cube will melt faster, the one on the metal plate or the one on the block of wood. Why?
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  5. #5  
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    Quote Originally Posted by Physicist View Post
    Typically I don't like doing students homework for them but with just the initial idea in this case I guess it's okay.

    Get a large block of wood and a rather large metal plate such as large frying pan. Let them both come to room temperature. Take someone from the audience and ask them to put one hand on the metal plate and the wooden block and then tell you which is warmer. Tell them to take their hands off now. Then take a cardboard stand and put "Warmer" in front of it and "Cooler" in front of the other so you and the audience can remember which is which. Then take two ice cubes, as identical as can be, and tell the audience that you're going to put an ice cube on top of each. Ask them which one will completely melt the fastest. Then put the ice cubes down on top of them and watch. It'll take about 15 minutes (You might want to do this on a video and record it and then play it in class).

    Which one do you think will feel colder? Which ice cube will melt faster, the one on the metal plate or the one on the block of wood. Why?
    Of course, the ice cube on the metal plate will melf faster than the one on the block of wood. Because metal is much much more conduct-heat than wood.
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  6. #6  
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    Quote Originally Posted by johnzxcv View Post
    Of course, the ice cube on the metal plate will melf faster than the one on the block of wood. Because metal is much much more conduct-heat than wood.
    Correct. It's not so obvious to everyone though. However its the magnitude of the melting difference that people get thrown by. Perhaps its better to use a plate which they claim is made of a special metal while the other is a typical counter top so as to show real life.

    I was wrong by the way. It takes only 8 minutes to entirely melt the ice cube, not 15 minutes (of course the actual time varies with the mass/size of the ice cube). In that time the one on wood hasn't melted at all. Only enough to wet the board just a tad.


    There were some people selling special plates which helped defrost meat faster. My friends uncle bought one and raved about it as did my friend. He was telling me that it was made of a special metal that helps things defrost faster. I thought about it a bit and realize what was happening. People normally put things out to defrost by putting them on the counter top which is rarely, if ever, made of metal. They're usually a non-conducting surface which typically means they don't conduct heat as well. So when you put something on a counter to defrost you're putting it on a thermal insulator. When my friends uncle bought it and tried it all he really did was place if from placing it on an insulator to placing it on a conductor. The conductor has to have a decent mass too otherwise it can't absorb and dissipate the heat fast enough. I tried this myself to see what happens. I put an ice cube in a steel pan and one on a wooden block. The ice cube on the metal plate melted fully took a 8 minutes compared to the one on wood took hours (as I recall. I'm repeating it right now).

    Actually it'd be better to just describe the story I just told you and melt the ice cubes like I just showed you. Then let people know that people use the public's ignorance of physics to relieve them of their hard earned money of gizmo's they have in their own home. Then tell everyone that the best way to defrost meat faster is by letting the meat actually touch a solid massive metal surface such as a frying pan making sure that the packing Styrofoam isn't between the meat and the metal.
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  7. #7  
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    Quote Originally Posted by Physicist View Post
    Correct. It's not so obvious to everyone though. However its the magnitude of the melting difference that people get thrown by. Perhaps its better to use a plate which they claim is made of a special metal while the other is a typical counter top so as to show real life.

    I was wrong by the way. It takes only 8 minutes to entirely melt the ice cube, not 15 minutes (of course the actual time varies with the mass/size of the ice cube). In that time the one on wood hasn't melted at all. Only enough to wet the board just a tad.


    There were some people selling special plates which helped defrost meat faster. My friends uncle bought one and raved about it as did my friend. He was telling me that it was made of a special metal that helps things defrost faster. I thought about it a bit and realize what was happening. People normally put things out to defrost by putting them on the counter top which is rarely, if ever, made of metal. They're usually a non-conducting surface which typically means they don't conduct heat as well. So when you put something on a counter to defrost you're putting it on a thermal insulator. When my friends uncle bought it and tried it all he really did was place if from placing it on an insulator to placing it on a conductor. The conductor has to have a decent mass too otherwise it can't absorb and dissipate the heat fast enough. I tried this myself to see what happens. I put an ice cube in a steel pan and one on a wooden block. The ice cube on the metal plate melted fully took a 8 minutes compared to the one on wood took hours (as I recall. I'm repeating it right now).

    Actually it'd be better to just describe the story I just told you and melt the ice cubes like I just showed you. Then let people know that people use the public's ignorance of physics to relieve them of their hard earned money of gizmo's they have in their own home. Then tell everyone that the best way to defrost meat faster is by letting the meat actually touch a solid massive metal surface such as a frying pan making sure that the packing Styrofoam isn't between the meat and the metal.
    That is quit an interesting story you have. I used to be tricked too. Do you know the trick immediately frozen a bottle of water? They said it was magical bottles, and they just touch the bottle and it was immediately freeze. And I bought it but after I tested it It doesn't worked. And I know I have been tricked. Soon later I understand that the bottles immediately frozen because the bottles was put in the freezerator in 2 hours, the temperature of the water reach 0 cecious , but the water doesn't form ice crystal yet, it need bubbles to form ice crystal and when you shake the bottles the water quickly form ice crystal and it immediately freeze.
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  8. #8  
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    Quote Originally Posted by johnzxcv
    Do you know the trick immediately frozen a bottle of water?
    No.

    Quote Originally Posted by johnzxcv
    They said it was magical bottles, and they just touch the bottle and it was immediately freeze.
    Whenever you hear someone use the term "magic" in modern life you know they're going to try to trick you using your lack of knowledge of science. I myself never heard of that thing with the ice happening. However it sounds like something a good chemist would know though or a physicist who knows his thermal physics well. I was always terrible at thermodynamics. But its the same sort of trick used on my friends uncle, i.e. relying on his ignorance of science.

    They show that thing with ice here - How to Make Water Freeze into Ice Instantaneously Science Experiments
    Last edited by Physicist; 09-04-2014 at 04:16 PM.
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  9. #9  
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    Quote Originally Posted by Gwen View Post
    Hello

    I'm a 16 year old student in search of a subject for an essay. The idea is that we start from a question and transform this into an experiment. Normally this wouldn't be a problem but I just can't think of anything that is impressing enough yet doable with our limited resources. Therefor if you have ever done something or now something which I could use I would be very grateful. Every idea is more than welcome.

    Greeting
    Gwen
    There are many, many interesting and relevant experiments that may be performed without a large budget.

    You can use a discarded CD or DVD as a diffraction grating. That, in turn, can be used for spectroscopy. It is easy, for example, to identify sodium with such a grating. Put some table salt in a Bunsen burner flame and you'll see what I mean. Copper lines also show prominently, as do the discrete lines of the light from neon bulbs and non-white LEDs. The broad, two-hump spectrum of white LEDs can be characterised quite nicely, too.

    You can use the grating to determine the wavelength of a laser pointer's light with high precision (you'll need to know the disc's track pitch, but you can look that up on wikipedia). Alternatively, if you know the laser pointer's wavelength, you can measure the track pitch, also to high precision. It's impressive that you can make such measurements to sub-10nm precision inexpensively.

    You can salvage the lens from a junk CDROM drive (or DVD drive) and attach it (with easily-removed hot glue, say) to your phone camera. This converts your smartphone into a microscope.

    Folks at CERN have published a number of papers intended for high school teachers (and their students). You might want to search for those to get more ideas for experiments that can be done with simple materials.
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