[paul.fr]

What you need

lemon Juice
A piece of Aluminium.
A cup


What you do

Part fill the cup with the lemon juice and then  put your piece of aluminium in to the cup. What happens? Why?

Explanation

You should see bubbles of Hydrogen (H2) gas, but why? Well this clever chap has the answer

[paul.fr]

What you need

A length of ribbon
A pair of scissers


What you do

Lay the ribbon on a flat surface and  run the flat blade of the scissors along the ribbon.

Explanation

The ribbon should start to curl, this is because one side of the ribbon becomes a bit longer than the other, the ribbon tends to curl in a direction that puts the longer side on the outside of the curl and the shorter side inside. Which is what these people said.

[Anastasia.fr.1]

as written by Robert Krampf:

y Grandmother is going to have her 103rd birthday this month. I have been thinking about how much the world has changed during her life. Imagine only having fruits and vegetables when they were in season. Imagine no computers, no television, no air conditioning, no refrigerators. This time we are going to step back in time a bit, and make our own butter.

To try this delicious treat, you will need:
a small container of heavy whipping cream
a glass of water that is half full

If you have never made butter, these instructions may sound strange, but trust me, it works wonderfully. The first thing to do is to let the cream sit on the counter, at room temperature, for about 12 hours. I put it out on the counter after supper, and I had freshly made butter on my toast the next morning.

After letting the cream sit, pour it into the glass jar. Don't worry if it has a slightly sour smell. Put the lid on the jar. Now we have to shake the jar, but we don't want to just start shaking it wildly. We want to watch what is happening. Give it one good hard shake about once every second. Watch carefully. For the first few minutes, not much will happen. Then suddenly, you will feel something solid hit the jar when you shake it. Look inside and you will see a large lump of butter. Give it a few more hard jolts and your butter should be ready.

Open the jar and look carefully. Around the butter is a thin, white liquid, which is commonly known as buttermilk. If you have ever had buttermilk biscuits, this is what they are made with. Pour off the buttermilk and add some cold water to the jar. Swirl it around a bit and then pour it off. Repeat this a few times, until the water remains clear. Drain all the water and put the lump of butter into a small bowl.

At this point, you have sweet cream butter, which is wonderful on hot bread or fresh biscuits. If you prefer salted butter, simply sprinkle some salt into the butter and stir it in. At this point, treat the butter just as you would the butter you get from the store.

That was quite yummy, but how and why did it work? First, we have to know a bit about milk. If you have ever been lucky enough to have milk fresh from the cow, you know that if you let it sit for a while, the cream floats to the top. That is because milk contains lots of tiny globules of milk fat, each surrounded by a thin membrane. Imagine tiny balloons filled with butter instead of air. Because the milk fat (butter) is lighter than the liquid, they tend to float. The cream that rises to the top is really a very high concentration of these fat globules floating on the milk. The milk from the grocery does not do this because it has been homogenized, a process that makes the fat globules small enough to keep them mixed evenly in the milk.

We left the cream out of the refrigerator overnight for two reasons. First, it helps the fat in the globules to form crystals. These crystals will help to break the membrane when we shake the cream. Imagine a water balloon with shards of glass inside. One jolt would cause the glass to slice through the balloon. That is what we want to happen.

Letting the cream sit at room temperature does something else. It allows lactic acid bacteria to grow. We think of bacteria as a bad thing, but many of them are quite useful. These bacteria make the cream more acidic, which prevents the growth of harmful bacteria. They also produce chemicals that give the butter a stronger and richer flavor.

When you shake the cream, some of the globules slam into the glass and break open. Soon, the cream is filled with tiny globs of butter. As these tiny bits of butter bump into each other, they stick together. The lumps of butter get larger and larger, as more and more globules are ripped open. Very quickly, you have one large lump of butter and a small amount of liquid buttermilk. I was amazed at how little liquid was left once the butter formed.

You will probably notice that the color of your butter is more pale that the stuff you buy at the store. Some manufacturers add yellow color, but a lot depends on what the cows are eating. Cows that eat grass get lots of a chemical called carotene, which adds a yellow color to the butter.

The true test of your butter is a fresh, hot biscuit or some crusty French bread.

Have a wonder-filled week.

[paul.fr]

Non-Newtonian Fluid on a Speaker Cone

Reader Jackson points us to an interesting video depicting non-newtonian fluid on a speaker cone. Basically, "corn starch is a shear thickening non-Newtonian fluid meaning that it becomes more viscous when it is disturbed -- when it's hit repeatedly by some thing like a speaker cone it forms weird tendrils." Video after the break.

 [ Invalid Attachment ]

video here
http://www.techeblog.com/index.php/tech-gadget/non-newtonian-fluid-on-a-speaker-cone

[112inky]

not sure if this is the right section for this topic, but here goes.

We all love the kitchen science part of the show, but what are your favourite kitchen science experiments? Either those featured on the show / podcast, or ones you have done yourself?

Why not post them here, and let us all enjoy the wonder of experimentation.

Just post the items you need, and how to conduct the experiment. Like the kitchen science on the show, please do not post what the final result is. That way we will not lose some of the enjoyment of conducting the experiment.

If a member is unsure of his/her results they could always pm the poster.


OK, here is a simple on to start thins off. I have already posted this somewhere, and there was some doubt as to whether it worked. so why not try for yourself and then post one of your own:

What you need

2 cups
about 15 copper coins
salt
a nail
and vinegar

What you do

place your copper coins in your cup and cover them with salt. Then pour in some of your vinegar, to about 1cm above the top coin.

leave for half to one hour, then drain the solution in to the other cup. At this point you will have shiny copper coins, but that is not the whole experiment.

With just the solution in the second cup, drop your nail in to it and wait another half to one hour.

What happens to the nail?

topic link

Why does vinegar make copper coins all pink and shiny? http://www.thenakedscientists.com/forum/index.php?topic=6240.0 [nofollow]

hey.. its a wonderful idea.. and i am gonna try it out on my own.... i am never allowed inside the kitchen for the reason i would mess it up....but.. i am gonna try this for sure..

[112inky]

What you need

A fat/chunky felt tip pen
A woolen cloth or jumer
A plate
Salt and Papper


What you do

Sprinkle some salt an pepper on to the plate. Then get your woolen cloth or jumper and rub it very hard along your felt tip pen for about 1 minute.

stop rubbing, discard the cloth/jumper and move the pen slowly over the plate.

What happens?

Hi i tried it.. but nothing happens... what would be the problem?

[Karen W.]

How to blow out a candle with sound waves!


What you need:

1 cardboard tube

Some thin plastic wrap or recycled plastic bag

Scissors

Scotch tape

1 Birthday candle

1  small dish

Sand or soil either one will do.


1. First you cover each end of the tube with some plastic wrap.. making sure it is snug and tight across the ends. Tape the plastic on snuggly.

2. Secondly you use your scissors to make a very small hole in the plastic at only one end of the tube.

3. Thirdly You then put some of your dirt or soil in the dish and stand your candle up in the dirt or sand. Use enough to hold your candle firmly up.

4. Next, if you are very young ask an adult to light the candle for you.

5.Now hold the end of your tube or "sound cannon" with the hole about 1 inch from the candle flame.

6. Next you should tap the end of the tube with your finger against the plastic wrap at the other end.Making sure you are still 1 inch from your flame....

What happens?

If you do it right it will sound as if you have tapped a small drum. The tapping of the plastic will then  cause the plastic to vibrate pushing the air inside your tube down and out through the tiny hole in the plastic creating enough force to blow out your candle!


[diagram=441_0]

[daveshorts]

This is actually more to do with smoke rings than sound. Have a look at
http://www.thenakedscientists.com/HTML/content/kitchenscience/exp/vortex-cannon/
for more info

[Karen W.]

thats interesting..I was trying to remember from the experiment how it wa done and  i am positive t wasa sound cannon... but perhaps my book is too old.. It was a science experiment book I did things with the kids with.. thanks Dave next week I will get te book out and copy the pages and see if It is just my memory or a too old and inaccurate book...I have the bookhandy.. bu have to wait for my cable service to be back up... It will be down about a week...
 thanks for sharing!

[gurpal]

how do you all come up with this stuff

[Chemistry4me]

By using their minds, but mostly the internet []

[wolfekeeper]

I just did a fun experiment. I made 'hot ice'.

Basically what you do is take vinegar (I used sarson's distilled malt vinegar) and some baking soda (sodium bicarbonate) and react them together (lots of foam!) This makes sodium acetate and lots of CO2 which bubbles off.

You then take it and boil it down (it took hours and hours and the place stank with the smell of salt and vinegar crisps!)

Once you've boiled it down you can let it harden off, and it will go like a bit like plastic.

Once it's set you take it and heat it up to around 100C in some kind of container (I used a tin) and it goes like water, and (if it's not contaminated) it will stay like that down to room temperature.

If you then add a crystal of the solid sodium acetate then it very rapidly crystallises and generates lots of heat (it's used in hand warmers).

Overall, it's quite fun.

You can also buy sodium acetate premade, but where's the fun in that?

[abecai63]

how do you all come up with this stuff

I was wondering the same thing. You guys are pretty creative.

[daveshorts]

Some I remember from childhood some i find in books, some from friends, some I invent, but most I find on the net. Though I often  tweak them a bit.

[Airthumbs]

Aluminium Can Battery

After reading through some of the kitchen science stuff I feel that this idea is worthy of its own post and thats what I have done.  After posting it I saw this section and will endeavor to include a description of the Aluminium Can Battery.


What you need



1 Aluminium can
About 1 meter of conductive wire. (I used the outer sheath of a coaxial cable).
A sponge
Some paper tissue towling
Some saline water. (I used 2 teaspoons of salt mixed into about 300ml of water).
A can opener
Some sand paper
Scissors


What you do

Using the can opener remove the top of the can.  Make sure the inside is clean. Be careful here as the top of the can is very sharp so it might be best to wear protective gloves to prevent cutting yourself! Take the sand paper and lightly use it to rub the inside of the can.  This helps to maximize the surface area in  contact with the saline solution, I think
Cut the sponge down so it is about the same length of the can.  Then using the scissors cut down the middle of the sponge but not all the way through, you should now be able to open the sponge up as if it were a cob, bun, or even bap!
Place the coaxial cable inside the centre of the sponge with about 2cm sticking out from one end, close the sponge, with what you have left begin to wrap the wire around the outside of the sponge starting at the opposite end you have from where the wire is sticking out and working your way towards the end with the wire sticking out about 2cm. Keep making the coils around the outside of the sponge until you have used up all of it. The final end of the cable can be just tucked under one of the coils you have made to secure it in place.
Now take the paper toweling and carefully wrap this around the outside of the sponge and wire.  The idea of this is to prevent the wire from touching the inside of the can.  Now push the sponge inside the can until you are left with just the top of the sponge visible with wire sticking out from the centre.
Now you are ready to pour the saline solution into the can, do this slowly as it takes time for the sponge to absorb the water, keep going until you almost reach the top of the can.

And that's it. You just made a battery.

I will be experimenting with variations of, wire length and saline concentrations to see if I can find the most effective combinations to produce a higher voltage and/or duration of the battery.  They normally last about an hour.

Lets try and make a difference, spread the word..  []  please let me know if you manage to get more then .18V, the video I saw they were getting about 1V, so I am not doing something right? 

Here is the link to the original video

Can the Naked Scientists please make a better one?

[CharlesCably]

the tortilla chips in your nachos look incredible  Howd you do them?  Fried in oil?
 
 I would have been happy with those chips, salted, and a beer
 
 Lee

[Slickscientist]

Dear everyone,
I have an activity that you can do with children. I got it from my science experiment book that my teacher gave to me as a present.

What you will need:

• some paint
• white spirit or oil
• paper(tracing/blotting)

How to do it:
First, mix the paint with some white spirit or oil.
Then, in a tub or deep dish, pour some water in.
After this, put in the paint. Because the paint is now oily, the water will repel it; give the mixture a swirl, dip a sheet of paper in and watch some art being created...

This is a simple example of offset printing. Enjoy,
Salik Imran.

[Slickscientist]

Baking is also nice but my parents won’t let me touch the hob; They don't want me to “cook up a storm!”
(Some thing come out unscathed...)

[miaturner95]

i tried this when i was in school and now i am motivated to try it again

[Arinece]

Another way is lemon if you want to shine copper. generally, It's more useful for those who are working with metal detection.