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Chemistry program ideas

Discussion in 'General' started by TJK, 28 Feb 2006.

  1. TJK

    TJK What's a Dremel?

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    I am in charge of doing 3-4 demonstrations of chemistry, lasers, physics, etc. for our advanced science class at my school. The juniors and seniors need to come up with experiments to do for 7th graders. These are for pure entertainment only, and are intended to create an appatite for the sciences. Past programs have included.
    -thermite reactions
    -laser shows
    -liquid nitrogen and dry ice
    -making things dissapear in liquid mixtures that refract light
    -coffee creamer flames

    anyway, our school has access to most anything reasonable we need, and we are welcomed to use it. I just need ideas for something new to do, or a spinoff on something old. A laser show would be cool, but I would need a little help.

    Any ideas are welcome.

    Thanks
     
  2. MonkeyTurnip

    MonkeyTurnip What's a Dremel?

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    how about something with magnets??

    or solid fueled rocket cars
     
  3. cpemma

    cpemma Ecky thump

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    How old is a 7th-grader? :confused:

    Tesla coil, you can light a fluorescent tube with no wires attached.

    Anyway, dozens of ideas for physics, a 2-minute search will find a list for other sciences. ;)
     
  4. Xiachunyi

    Xiachunyi What's a Dremel?

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    I think 7th graders are about 12/13 yrs old.

    Magnets are a good idea: Ferrofluid

    Another idea: Making things resonate by matching frequencies (tuning-forks)
     
  5. thecrownles

    thecrownles What's a Relix?

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    get a speaker and a board with a hole in it, some sound software, and resonate crystal glasses until they shatter (this idea stolen from mythbusters)
     
  6. offroadracer789

    offroadracer789 What's a Dremel?

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    there is a gas experiment where u light a cotton ball soaked in alcohol, put it in a flask, then put a hardboiled egg on top.

    When the air in the flask comes back to room temperature, the egg is pulled inside of the flask.

    7/8 graders love explosions and fire. Thermite is way overdone. You could try basic stuff like sodium and water. Smoke bombs are cool, especially to my 7/8 grade neighbors, but i wouldnt reccomend them since someone may have asthma.
     
  7. TJK

    TJK What's a Dremel?

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    lots of good ideas- stuff that caught my eye and def. need more explaining

    cotton ball and egg
    shatter crystal glasses - anyone know anything about this? btw i did see mythbusters, but dont remember how they did it
     
  8. SensesFail

    SensesFail Guest

    The coolest thing I have ever seen science experiment wise was supercooled magnetic levitation.

    http://www.fys.uio.no/super/levitation/

    Liquid nitrogen is cheap (yet slightly dangerous). I have no idea what the superconducter is (I think it is yttrium-barium-copper oxide, good luck finding that), but the magnet is probably just your run of the mill neodymium rare earth magnet.

    You can also get the same effect by spinning a magnet at a few thousand rpm's over a steel (might also be magnetic) plate. Just google magnetic levitation. My brother showed me that experiment once. It's pretty easy if you have the means to do it (a dremel would probably spin a correctly shapen magnet fine).

    You can also try H202 (Hydrogen Peroxide) rockets. You need a silver grate (as a catalyst) and 90-95% pure Hydrogen Peroxide. Force the H202 over the grate and you get super heated steam and thrust. Its what Bell used for their jetpacks in the 1960's. While this experiment would be awesome, the liabality and impracticality seems high...especially if this is a high school class.

    Look here for ideas:

    www.unitednuclear.com

    I used to want to carry one of these magnets in my backpack at school to see what would happen. After remembering that knives and other sharp objects are made of steel I've long since given up that idea.

    [​IMG]
     
    Last edited by a moderator: 1 Mar 2006
  9. Stuey

    Stuey You will be defenestrated!

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    Get a bunsen burner or equivalent flame, soda cans (or taller iced tea cans) and fill them with a little water. With tongs, place the can over the flame until the water boils out and vapor fills the can and escapes the spout. (Shake the can to ensure little or no water remains.) Then, quickly flip the can (or drop it upside down) into a tub of water. The can will implode since the vapor in the can will liquify when the hot can touches the cooler water. The vapor condenses, leaving a partial vacuum in the can. Due to lower pressure inside the can and higher pressure outside, the can implodes.

    Also, the egg drops into the flash because the flame burns up all the oxygen in the flask. It creates a pressure difference between the inner flask and the outer environment. This has nothing to do with air temperature, it's all about pressure. The egg (hard boiled I assume) is sucked into the flask.

    What you can also do get a liquid nitrogen dewer and fill it up mostly with liquid nitrogen. Have a hole in the top of the dewer with a cork, Or get styrofoam and make a makeshift lid. Drop a test tube in so that most of it is submerged and the mouth is open to the air. If you do this, make sure that the room is ventillated or people will start to feel uncomfortable. Since the air gathering in the test tube is being chilled (remember, most of the test tube is submegred below the liq. N2 surface level), it will liquify very slowly. As it liquifies, its volume decreases and more air is drawn into the test tube. Gradually, a LOT of air will gather and liquify in the test tube. During this time you can perform other experiments. After time passes, using special cryo-gloves and show that there is a liquid level in the test tube (use a larger diameter test tube for best effect). You can either carefully put a balloon over the test tube and place the combination in a test tube holder and have them watch the baloon inflate. Or you can ask what the liquid is and then spill it in a flat open container and show them that it evaporates back into the air.
     
  10. TJK

    TJK What's a Dremel?

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    so is there such a mp3 file that can be cranked up to shatter glass? if there was..that would be sweet
     
  11. SensesFail

    SensesFail Guest

    Air temperature determines air pressure. It has nothing to do with fire consuming the oxygen. Matter is only changed, never consumed. It's not like there is a vacuum because matter magically disappered. The effect is best seen by putting a flask in warm water, placing an egg on top, and then placing the flask on ice cold water. The egg will suck in.

    Warm air expands, cold air contracts. Given an equal amount of air in a confined space (such as a flask sealed by an egg), as air warms up the pressure rises. When air cools, the pressure decreases.

    It's all about harmonic frequency. If you can match the frequency and amplitude at which glass shatters (a high pitch sound and loudness), then you can shatter glass. It'll probably depend on whether you speakers can reproduce the frequency since most are limited to 20hz-20khz. It's possible if you have nice enough equipment and friendly neighbors to cope with the piercing tone required.
     
    Last edited by a moderator: 1 Mar 2006
  12. TJK

    TJK What's a Dremel?

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    oh a 7th grader is like 12 years old
     
  13. Stuey

    Stuey You will be defenestrated!

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    Matter doesn't magically disappear? Gosh darnit, you could have fooled me. :D

    But yea, warm air expands, cold air contracts. By itself, this means nothing to the experiment. This is relevent only because the egg does not form a seal with the flask. The egg falls in because as the match burns itself out, it heats up the air inside the flask which escapes in small amounts through the mouth of the flask. Even though only a little bit of air escapes, as the match goes out, the air inside the flask condenses (as you agree with), creating a pressure differential. At room temperature, the amount of air inside the flask is now LOWER than when the match started to burn. Since the volume remains the same, and the temperature is the same, but the amount of air decreased, the pressure is lowered to compensate and promote equilibrium. Since the pressure is lower than the ambient air pressure (even if by a minute amount), it's enough of an effect for the egg to be pushed into the flask.

    I should have chosen my words more specifically in my initial post, but I didn't think anyone would need clarification as I explained the theory in my description of the imploding can experiment. Had you read my post in its entirety, you would have seen that there was no need to remind me that matter doesn't magically disappear.
     
  14. Rocket733

    Rocket733 Austerity - It's the only way

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    The flame test is cool. You just used a bunch of different compounds (copper, iron, sulfur, etc) and soak them in alcohol and then set them on fire. They'll burn different colors and it looks pretty sweet.
     
  15. Techno-Dann

    Techno-Dann Disgruntled kumquat

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    Use electrolysis on water to get hydrogen and oxygen, then conclude the show by mixing the two and tossing in a match.
     
  16. Rd52

    Rd52 Minimodder

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    yes do the flame test its awesome even for me a 16 year old :p, u might want to do some minor explosions those are always fun
     
  17. SensesFail

    SensesFail Guest

    Then say that. When you say stuff like:

    you sound like an idiot.

    In your first post you explained your experiment fine, but when you tried to reason what is going on you lose me. I'll give you more credit from now on and I'll try to pick out what seems right no matter what you say. It'll be like a garagesale...pick what you like. :) Ehh...I'm starting to feel like a dick. Sorry about that.
     
    Last edited by a moderator: 1 Mar 2006
  18. Eliminos

    Eliminos What's a Dremel?

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    A few good experiments I have seen (if I can remember them correctly)

    Strong Hydrogren Peroxide + Potassium Iodide + A tiny bit of washing-up liquid (dish-soap): Squirt the soap into around the sides of a tall glass container. Add the potassium iodide crystals and then add the hydrogen peroxide. You should get a huge expansion of foam. You might want to try this out a few times, I can't remember how much of the reactants gives foam that won't engulf the whole class

    Sucrose + Strong Sulphuric (Sulfuric) Acid: I think it was sulphuric acid that this experiment worked with. What happens is it extracts the carbon from the sucrose and leaves it as a black spongy mass in the test tube.

    Luminol + Sodium Hydroxide: Not sure of the concentrations or quantities but it glows when the two chemicals are mixed.
     
  19. hitman012

    hitman012 Minimodder

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    This is quite a good experiment - check here for some interesting mixtures of the reactants.
     
  20. JCG

    JCG What's a Dremel?

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    Anything that smokes or explode will get their attention :naughty:
    But there was another reaction I loved when I had chemistry. I can't remember what it was. I think leadnitrate with something else. But If your put the two fluids together it turned yellow.
     

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