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Experiments Feedback

by Ron Kurtus

Readers have sent in a total of 162 comments and questions on Experiments issues. They are listed according to date.

You can read them to further your understanding of the subject.

List of next 15 letters




Putting a lot of insulation to make a thermos Thermos Canada
Has to make a thermos using non-commercial materials Thermos Canada
Where should the black paint be? Thermos Canada
Thermos project Thermos Canada
Not sure what materials to use Thermos Canada
I need a good science fair experiment Matter States Egypt
Making thermos from pop bottle Thermos Canada
Should I put aluminum foil on the inside? Thermos Canada
Wrapping bubblewrap around a plastic bottle Thermos Canada
Doing an experiment filtering water Fluids USA
Wants to use cotton balls for insulation Thermos USA
What are the best insulators? Thermos Canada
Magnetic levitation experiment Magnetism Canada
Idea for experiment to make sparks Static Electricity USA
Mixing cornstarch and water Matter States USA

Next 15 letters


First 15 letters


Putting a lot of insulation to make a thermos

May 5, 2007


i have to do a project where i have to make a thermos. it has to stay hot or cold for 3-5 hours and i didn't no if i put the right insolaters in it, i used:
~a towel
~tin foil
~paper (alot of layers)
~and ALOT of duck tape to put it together, i wraped it around a thick plastic cup
P.S. it has to be abel to hold 500ml
k thx

- Canada (13715)


The tin foil should be wrapped around the plastic cup, but it does so little that it really is not necessary.

You need to make sure the cover is insulated too. It sounds like you have more than enough insulation. Test it out by putting some ice cubes in the cup and leaving it sit for a few hours. You can see how cold the water still is and how much the cubes have melted.

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Has to make a thermos using non-commercial materials

April 17, 2007


I have a school science project. We have to make a thermos using non-commercial materials, basically home-made. 100 mL of hot water will be poured in it and we will see which group has the best thermos. Right now, I'm not sure where to start off. I don't know if I should be using heat conducting metals, insulating materials, or a combination of both. Our group has access to fleece, I'm not sure if that is more useful than styrofoam. And also, as long as the "thermos" fits on our desk, it's ok. So it could be pretty big. Please give me some suggestions(and for the lid too). Thanks in advance!

Dale - Canada (13593)


Look at our reader feedback in the Thermal Insulation lesson to see what other students have done. Also look at our lesson on Thermos Containers at:

You want to use non-conducting or insulating materials. Fleece could be a good insulator. Start with a glass or plastic jar and wrap it with some insulating material. You can put the jar in a larger jar or simply tape the insulating material.

You can do some experimenting by making a simple thermos and putting it in the refrigerator for a while to see how well it works in keeping the water hot. Then you can decide if you need more insulation or a better configuration. Work your way up until you are able to meet the requirements of the experiment.

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Where should the black paint be?

April 12, 2007


I am making a thermos for my project. But what i don't understand is when you put the smaller jar inside the bigger jar, where should the black paint be, in the smaller jar or the bigger?

Alex - Canada (13555)


Look at the Reader Feedback on the Thermal Insulation page. There are a number of descriptions there.

If you are trying to keep things cold, you really should not have black paint. Insulation is the most important.

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Thermos project

April 7, 2007


Okay , I have to make a thermos in Science class. I must keep a 355ml can of cold water refridgerator temperature for 4 hours. Here is my idea:

Wrap the can and the inside of a small glass jar in aluminium foil(shiny facing in)
Spray the inside perimeter of a larger glass jar with spray foam.
Wrap the lid of larger jar with Styrofoam.
Put can in smaller jar, and put it in the larger jar.
Put packing peanuts in the space left at the top.
Wrap the outside of the jar in bubble wrap and secure it.

Would these steps work ?

I also have some questions; Should I worry about black attracting heat ? Should I use glass or plastic jars? Is the aluminium foil for hot or cold ?

Thanks a million !

- Canada (13505)


It is preferred not to have black, because it absorbs some heat. Aluminum foil reflects radiant energy inward. It is usually used to keep things warm. You really don't need the foil in trying to keep things cold. Both glass and plastic work well as insulators and to hold your pop can.

The idea of having two jars is that the outer jar will hold in the insulation, if you use some loose insulation like packing peanuts. If you are using sheets of material, you can just have one jar and wrap it with the material and tape it down.

If you will use two jars, make sure the pop can will fit in the smaller jar. The foil is wrapped around the smaller jar. With all the insulation you are using, it should keep your can cold. You might try a simple experiment for a to see how well it works for just a few hours. then if you need to, you can add insulation until you get enough for the four hours.

Best wishes in your project. (Who gets to drink the pop?)

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Not sure what materials to use

February 26, 2007



hi! so.. um.. i'm not really sure with wat materials to use to make a thermous.
and how and where to put the materials? and wat materials will make the water inside my thermous to stay warm for atleast 3 hours.

also i did look at your feedback from other students but its not halping that much. can u plz help me??? this project is due in 2 dayz.


rup - Canada (13252)


Take a jar that has a screw top, so that you can fill it with hot water. Wrap the jar in some insulating material. You can use Styrofoam or even some home insulation material. But if that is not available, you can use layers of bubble wrap or even newspaper. If you use newspaper, it needs to be a number of layers at least 1 inch thick.

There also needs to be insulation on the bottom of the jar, as well as the lid. The metal lid is a great place for heat loss.

Put some hot water in your thermos, seal it up, and put it in the refrigerator for a half-hour. In this way you can tell if you have enough insulation.

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Matter States

I need a good science fair experiment

February 20, 2007


i need a good science fair experiment quickly becsuse i need it k

mostafa - Egypt (13209)


Try to demonstrate a principle you have seen in physical science in an area of interest and then explain why it works. One example is to show how the freezing point of water changes by adding salt in the water.

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Making thermos from pop bottle

February 18, 2007


Hello! I have to make a thermos and i HAVE to use a 2 litre pop bottle. So My idea is to wrap the outside of the pop bottle in aluminum foil. Then use liquid glue to put them together. Do you think that this will work? Can i use something either than aluminum foil? Should i wrap the aluminum foil around anywhere else; either than the outside?

Mariam - Canada (13198)


You can wrap the outside of the bottle in aluminum foil, but then you need to wrap insulation material around the bottle and the foil, otherwise it won't work properly. You can wrap the bottle with Styrofoam, bubble wrap, read a newspaper. Then you can wrap that in tape to keep the whole thing together.

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Should I put aluminum foil on the inside?

February 13, 2007


HI! you said that a black outside would absorb a small amount of external radiated heat and it wouldn't absorb radiated heat from inside, since there would be insulated in the way. So if it would't absorb a small amount of heat from the inside will it work better or worse. which one do you think is better; Having aluminum foil on the inside and outside or having aluminum foil on the inside and Black on the outside. And by the way how could u make da outside black, like with paint or construction paper? Please awnser a.s.a.p!!

Mariam - Canada (13149)


If you had a clear bottle, and you were using hot liquid inside of it, wrapping the bottle with aluminum foil would reflect some of the radiated heat back into the container.

Putting black material on the outside of the installation is much more work than is necessary, and it probably wouldn't help any.

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Wrapping bubblewrap around a plastic bottle

February 13, 2007


Do you think that my idea will work? It's to have a plastic bottle. Then bubble wrap around the inside of the bottle. And then to have a foam cup in the plastic bottle with the bubble wrap surrounding the foam cup. Do you think that this will work. And if it does for about how long? please awnser this. My thermas is due in 3 dayz!!!!!!!!!!!!!!! And i have to do a report on it too!!

Mariam - Canada (13150)


Have a container that has a cap on it. The plastic bottle will serve that purpose if you are just going to put liquid into it. Then you can wrap a bottle bubble wrap, towels, or even newspaper. You can then tape the material together.

The thickness of the material you wrap around a bottle will determine how well it holds the heat or cold inside the bottle.

See our Reader Feedback on Thermos Container for more ideas.

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Doing an experiment filtering water

February 8, 2007


My son is in the 6th grade and he has a science fair coming up. He is going to
do an experiment on different filters you can make to filter all kinds of nasty
water, dirt, salt, and sand. The question that he has is that when he filters
the salt water how could he tell if it filtered and how much? Is the water
drinkable? He say along time ago that these kids made a homemade salt meter by
using aluminum foil, wire, 9V battery, a buzzer, and pencials. When you put this
in the salt water the buzzer goes off, after filtering the salt water, the buzzer should not. The problems is the meter works when you touch the two sticks
together but not if you put it in the salt water, like he saw it do. What are
we doing wrong? Please help my son Kris. Thank You

- USA (13093)


Although you can filter out materials that are mixed in water, such as dirt and sand, you really can't filter out salt in the water. Dirt is a mixture in water, and its particles are large enough to be filtered out. Salt is a dissolved solution, and individual atoms cannot be filtered.

See our lessons on Mixtures and on Solutions.

Salt water conducts electricity, while pure water doesn't. You could use two wires, the battery, and either a flashlight bulb or a buzzer to show this. When the wires are touched together with this circuit, the buzzer should go off. Likewise when the two wires are put in salt water, the buzzer should go off. But it should not go off in pure water.

The only way to get rid of the salt in salt water, is to boil the water and collect what gets boiled off. Boiling away the water will leave salt in your pan.

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Wants to use cotton balls for insulation

February 7, 2007


we are making a thermos for school and were wondering what would be a good insulator. We were thinking of using these following materials:

Cotton Balls
Slipper Socks/Furry Socks

Those are some materials we were wondering about.

Please respond


Saqloana - USA (13080)


Those items would be good insulators. Bubble wrap and Styrofoam are also good.

Look at our Reader Feedback in the Thermos lesson to see what other students have used.

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What are the best insulators?

February 7, 2007


Ok so my gruop and I are wondering what make the best insolaters for making a home made thermos. We really need to know because we want an (A+)!!!!

Leo - Canada (13081)


You can use bubble-wrap, Styrofoam, and even newspaper to insulate your thermos.

Look at our Reader Feedback in the Thermos lesson to see what other students have used.n.

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Magnetic levitation experiment

February 5, 2007


the experiment we tried was magnetic levitation.

We had two 6v batteries that, when hooked together (ie. a wire connecting the pos. and the neg. poles) produced 12v. we then, took a normal nail and wrapped copper wire around the nail about 45 times. we then connected the wire from the head of the nail and connected it to the pos. pole of the battery and the wire that came from the point of the nail was hooked to a switch and from the switch went to the neg. pole of the battery.

the experiment then said to place a small magnet above the copper wrapped nail. when the switch was turned on, the magnet was suppose to be repelled by the copper wrapped nail, creating magnetic levitation.

when we turned the switch on, nothing happened. we noticed that the nail became magnetised, because we put a paper clip to the nail and it stuck to it, but no levitation. we tested to see if the current was going through and it was.

My question is why do you think this experiment failed to levitate the magnet.
thanks for your time
sincerely yours

robert - Canada (13064)


You set up an interesting experiment, even though it didn't work out as planned.

Magnetic levitation either requires special materials that repel magnetism or magnetizing an object and then putting the same poles together (i.e. N to N) so that they repel.

You can evaluate what went wrong, but at the very least you put together a good experiment and should not consider it a failure.

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Static Electricity

Idea for experiment to make sparks

February 4, 2007


Making Sparks

In this experiment we'll create an object called an electrophorus. Using the materials listed above, we'll charge the object and then discharge it creating a snap, a little electrical shock, and a bright spark. If you're afraid of a little electrical shock then get Dad to discharge the object for you. And for grins, don't tell Dad beforehand about the resulting spark and shock. After all the amateur garage projects Dad has worked on, he's bound to be used to electrical shocks by now...
1. Place the pie pan upside down on the table.

2. Push a thumbtack down through the center of the pie pan.

3. Turn the pan back over so you are looking at the inside of the pan. The point of the thumbtack should be sticking up through the middle of the pan.

4. Coat the thumbtack point with hot glue. (Im sure you figured out that the word 'hot glue' comes from the fact that the glue is HOT! So be careful).

5. Push the eraser end of the pencil down onto the thumbtack.

6. Let the glue dry for a little while.

7. Rub the styrofoam plate with the wool rag for about 45 seconds.

8. Place a styrofoam plate upside down on the table.

9. Using the pen 'handle' that we just created, place the pie pan on top of the upside down styrofoam plate (the pen should be sticking up).

10. Quickly touch the pie pan with your finger. It may produce a small shock.

11. Remove the pie pan off of the styrofoam plate using the pen 'handle'.

12. discharge the 'charged' pie pan by touching it with your finger. If you feel mildly unpleasant about a small electrical shock then use Dad as the discharge object. Foreheads and ears make good targets - just make sure you have an escape route planned beforehand.
Pretty cool, huh? You can recharge the pan by starting at step 8. After Dad has seen (or felt) the results of this experiment, feel free to have a little fun and chase him around the room with your newly built zapper.
So what have we learned here (besides the fact that Dad's can indeed glow in the dark)?

Rubbing the styrofoam plate with the wool rag creates a negative charge on the plate (that is, it attracts electrons from the wool). When you place the pie pan on top of the styrofoam, the electrons on the styrofoam repel the electrons on the pan. The pan at this point has a neutral charge. But when you touch the pan (while it is on the styrofoam plate) the electrons travel off of the pan and onto your finger (possibly creating a spark). Now the pan has a positive charge.

Now, by carrying this contraption by the insulated handle, you can carry a positive charge all around the room. When you bring this positive charge near your finger, or any other object that is a source of electrons, the positively charged pan will attract electrons, creating a spark.

(Although an atom is normally electrically neutral, it can lose or gain a few electrons in some chemical reactions or in a collision with an electron or another atom. This gain or loss of electrons produces an electrically charged atom called an ion. An atom that loses electrons becomes a positive ion, and an atom that gains electrons becomes a negative ion. The gain or loss of electrons is called ionization).

gitty - USA (13053)


Thanks for the idea and procedure for your science project.

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Matter States

Mixing cornstarch and water

January 20, 2007


In biology one day, my teacher had us do a simple states of matter experiment. We mixed cornstarch and 1/2 as much water together. (From what I hear this is a very common experiment.) When we played with the substance it was kind of hard, but when we let it sit there and not do anything with it, it turned into a liquidy substance. My question is what state of matter is it? Because so far we only know about 3 differnt kinds of matter. So with that information, we had to conclude that it was 1/2 liquid and 1/2 solid. But I want to know exactly what it is.

High School Student - USA (12915)


The combination of water and cornstarch is a special mixture over a liquid and solid. It is called a suspension and to have some unusual properties.

See our lesson on Mixtures at:
Chemical mixtures.

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