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Author Topic: What's your kitchen science?  (Read 398058 times)

Offline Bass

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Re: What's your kitchen science?
« Reply #200 on: 16/10/2007 04:41:40 »
Everyone is fascinated with volcanos- and almost all of us have seen the model volcanos erupting with vinegar-baking soda-food coloring.
For different type of volcano model that shows how craters (calderas) form here's an easy demonstration:

Get a box, at least 2 feet (65 cm) square, and seal the inside bottom with tape (otherwise you end up with flour on the floor).  Punch a small hole in the bottom, and stick a bit of tubing through the hole.  Attach the tubing inside the box to a small ballon (rubber bands work well).  Inflate the balloon, then build a mountain of flour (or some other fine grained material) on top of and around the balloon (but all contained in the box).  Slowly release the air from the balloon, and the collapse crater will form on the top of the flour "mountain".  Varying the rate of balloon deflation will change the pattern of the crater.
Another suggestion was to use different colored layers of flour to better demonstrate what happens during collapse.
 

paul.fr

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Re: What's your kitchen science?
« Reply #201 on: 16/10/2007 15:08:02 »
Excellent. Thanks for the contribution, Bass.
 

paul.fr

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Re: What's your kitchen science?
« Reply #202 on: 25/10/2007 22:28:47 »
what you need

a balloon
a hexagonal nut without any sharp edges


what you do

pop the nut into the balloon and inflate it, tie the balloon off, and whilst holding it move the balloon in such a way that the nut rolls around inside.

do not hold the balloon tight in both hands, just a light grip from two fingers off each hand will do.

what happens?
 

paul.fr

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Re: What's your kitchen science?
« Reply #203 on: 25/10/2007 22:42:00 »
what you need

a candle that's the same width all the way down
matches
two glasses that are the same height
a darning needle
a knife
a room without a breeze
an adult to help you with the knife, the needle & the matches

what you do

cut the bottom 1cm off the candle so the wick is exposed, and poke the darning needle through the middle of the candle (the closer to the middle you are, the better it'll work).
put your two glasses upside down and balance the ends of the needle on them, so the candle can swing through between them.
make sure the candle is balanced, and then light one end and then the other.

wait...what happens?

with a knife and matches used in this experiment, child supervision is essential.
 

Offline techmind

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Re: What's your kitchen science?
« Reply #204 on: 27/10/2007 00:50:45 »
Neat video:

What you need
A flat-headed screw, 3 to 6cm long
Small, fairly strong round (disc) magnet
20cm of wire
'D' or 'C' cell ALKALINE battery  Do NOT try a rechargeable battery as this would be very dangerous

What you do
Stick the magnet onto the head of the screw
This should magnetise the screw sufficiently that you can hang the pointy end of the screw from the underside of the battery (see video)
Hold one end of the wire to make contact with the top end of the battery
Tickle the other end of the wire on the magnet or screwhead

Caution: Don't hold the wire connected to the screwhead for more than a few seconds as you are effectively short-circuiting the battery - you'll flatten the battery quite quickly and it could even get hot.

Caution: Absolutely DO NOT attempt to use any kind of rechargeable battery (NiCd or NiMH etc) as owing to their much lower internal resistance a very large current will flow, probably enough to melt the wire... at the least you'll burn your fingers, at the worse the battery could explode


It's too late at night for me to figure/explain why it works in detail, but it's all to do with the magnetic field around current-carrying conductors. I'm sure it's much the same explanation as an old experiment where you have a suspended wire dipping in a dish of mercury (probably banned these days!)

If you reverse the battery OR the magnet, the direction of rotation should change.
« Last Edit: 27/10/2007 00:53:05 by techmind »
 

paul.fr

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Re: What's your kitchen science?
« Reply #205 on: 28/10/2007 18:52:11 »
what you need

a clear jar or vase with a wide opening
baking soda, or bicarbonate of soda
vinegar
bubble mix and a bubble ring


what you do


put a few spoons full of baking soda in the jar and pour in some vinegar so it bubbles about halfway up the jar.

when the bubbles settle down a bit, swirl the mixture around to help the baking soda dissolve, then blow some bubbles up nice and high, and catch one in the jar.

what happens to the bubble you caught in the jar?
 

paul.fr

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Re: What's your kitchen science?
« Reply #206 on: 28/10/2007 18:59:43 »
what you need


2 balloons
a piece of rubber hose about 15cm long and wide enough for the balloon mouth to fit around snugly
someone to help you hold the balloons


what you do


blow one of the balloons up to normal size, and get your friend to hold the neck of it tightly while you blow the other one up to half that size

don't tie the balloons off!

put the mouth of the balloons onto the ends of the rubber tubing without letting too much air escape, and without letting go of the neck of the balloon. once both balloons are attached to the tubing, let go of their necks at the same time

what happens!
 

paul.fr

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Re: What's your kitchen science?
« Reply #207 on: 03/11/2007 21:47:04 »
what you need

a marble
a bendy straw


what you do


bend your straw into an L shape and then put the straw in your mouth, so the short bit sticks up like a pipe.
hold the straw in place and balance your marble on the end of the straw, nowblow through the straw.

what happens!
 

paul.fr

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Re: What's your kitchen science?
« Reply #208 on: 03/11/2007 21:53:58 »
what you need

coloured water, cordial, cola...any liquid with a colour
glass
2 straws


what you do

Fill the glass with your chosen liquid, and put one of the straws in and hold it up straight Don't let the straw rest on the bottom of the glass. Now, hold the other straw so the end of it touches the top of the first straw and blow!

what happens?
 

Offline daveshorts

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Re: What's your kitchen science?
« Reply #209 on: 04/11/2007 12:24:48 »
If you want an explanation for the floating marble one has certain similarities to:
http://www.thenakedscientists.com/HTML/kitchen-science/in-lab/exp/the-aerodynamics-of-a-ping-pong-ball/
 

paul.fr

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Re: What's your kitchen science?
« Reply #210 on: 11/11/2007 19:08:39 »
Make a square bubble.

what you need

pipe cleaners
bubble mixture


what you do

use the pipe cleaners to make a 3D square, and dip it in to your bubble mixture. you may get some extra round bubbles, these can be easily popped to leave a nice square bubble.



why does it do that?
when one bubble is surrounded by other bubbles, it can make stable shapes with corners and sides. Try making a 3D triangle...go on..
 

paul.fr

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Re: What's your kitchen science?
« Reply #211 on: 18/11/2007 11:41:37 »
what you need

a bank note
2 paper clips

what you do

fold the note in to a "s" shape, and attach the paper clips where the "o"s are in this very bad diagram


holding the sides of the note, gently pull to straighten the note out.
what happens to the paperclips?
 

paul.fr

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Re: What's your kitchen science?
« Reply #212 on: 18/11/2007 11:52:22 »
what you need

two coins of the same value

what you do

place one coin in each hand, as shown in the pretty poor diagrams.

left hand.


right hand.


yes, they are the worst diagrams you have ever seen....any way. the coin in your right hand should be in the middle of your palm, and the coin in your left hand needs to be close to your thumb..this is obvious in the diagrams!

now turn your hands so they are palm down, where are the coins?


*****can anyone do better diagrams? if you can please feel free to edit mine...please

whats happening

rotational mechanics

When you turn your hands over you're rotating them around their centre point, which is near the middle of your palm. The coin in the middle of your hand will just drop straight down, so it'll stay under that hand. But the coin out near your thumb gets rotated around the centre point of your hand, and that flicks it over under your other hand.
« Last Edit: 18/11/2007 11:54:38 by paul.fr »
 

paul.fr

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Re: What's your kitchen science?
« Reply #213 on: 12/01/2008 16:52:30 »
In honour of this weeks, Question of the Week - How do Boomerangs Work?

What you need

cardboard or thick paper
a pen or pencil
scissors

What you do

draw a cross shape (like two plasters overlapping to form a cross), and cut it out. slightly bend all four ends in the same upwards direction.

Place your 'boomerang', slightly over the edge of a table and flick it.
 

Offline Karen W.

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Re: What's your kitchen science?
« Reply #214 on: 12/01/2008 17:07:31 »
what you need

two coins of the same value

what you do

place one coin in each hand, as shown in the pretty poor diagrams.

left hand.


right hand.


yes, they are the worst diagrams you have ever seen....any way. the coin in your right hand should be in the middle of your palm, and the coin in your left hand needs to be close to your thumb..this is obvious in the diagrams!

now turn your hands so they are palm down, where are the coins?


*****can anyone do better diagrams? if you can please feel free to edit mine...please

whats happening

rotational mechanics

When you turn your hands over you're rotating them around their centre point, which is near the middle of your palm. The coin in the middle of your hand will just drop straight down, so it'll stay under that hand. But the coin out near your thumb gets rotated around the centre point of your hand, and that flicks it over under your other hand.

Yes your thumbs are on the wrong hands! Cool experiment.. I will try it!
 

Offline Karen W.

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Re: What's your kitchen science?
« Reply #215 on: 12/01/2008 17:16:51 »
what you need

two coins of the same value

what you do

place one coin in each hand, as shown in the pretty poor diagrams.

left hand.


right hand.


yes, they are the worst diagrams you have ever seen....any way. the coin in your right hand should be in the middle of your palm, and the coin in your left hand needs to be close to your thumb..this is obvious in the diagrams!

now turn your hands so they are palm down, where are the coins?


*****can anyone do better diagrams? if you can please feel free to edit mine...please

whats happening

rotational mechanics

When you turn your hands over you're rotating them around their centre point, which is near the middle of your palm. The coin in the middle of your hand will just drop straight down, so it'll stay under that hand. But the coin out near your thumb gets rotated around the centre point of your hand, and that flicks it over under your other hand.

 ok I tried it, the right hand was definitely as you stated but the left coin did not end up under my other hand.. it ended up right at the outer extension of my left thumb as if my thumb was an arrow pointing to it Right at the tip of my left thumb, but not under my hand!

I was careful to place the coin close to my left thumb and the other in the center of right palm!
 

paul.fr

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Re: What's your kitchen science?
« Reply #216 on: 22/01/2008 16:07:43 »
what you need

A hand


what you do

Bend your middle finger and place the centre section on a table or hard surface. You will be able to lift your thumb, index, and little finger without moving your middle finger. But can you lift your ring finger?

 

paul.fr

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Re: What's your kitchen science?
« Reply #217 on: 22/01/2008 16:10:57 »
what you need

A hand
A foot / leg


what you do

Lift your right foot a few inches from the floor and then begin to move it in a clockwise direction. While you're doing this, use your right index finger to draw a number 6 in the air. What happens to the direction you are turning you foot?
 

paul.fr

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Re: What's your kitchen science?
« Reply #218 on: 24/01/2008 13:36:26 »
what you need

2 iron nails
2 glasses (small wine or sherry glasses are ideal)
cooled water (boil a kettle of water then allow the water to cool until it is just warm)
Olive or sunflower oil
Wire wool / fine sandpaper

what you do

Clean each of the nails with wire wool or fine sandpaper. Fill the two of the glasses with cooled water, enough to cover the nail, but leaving a fingers depth unfilled. Add a nail to each of the glasses, and then pour a layer of oil over the water in one of the glasses. The oil will float to the top of the water and form a separate layer which should be about 1cm thick. Leave somewhere where they will not get knocked for 24 hours.



What happens to the nails?
« Last Edit: 24/01/2008 13:42:46 by paul.fr »
 

Offline Cameron Lapworth

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Re: What's your kitchen science?
« Reply #219 on: 31/01/2008 01:54:50 »
This is an oldie but a goodie,

What you need a shallow dish with a flat bottom
a candle
a glass
matches
water.

1.attach the candle to the middle of the dish it will need to hold a certain amount of water so not too flat, a bowl with a flat bottom is ideal.

2. pour a couple of centimeters of water in the dish/bowl and light the candle

3.  put the glass over the candle (candle may need to be cut short to fit, don't use a tea candle).

If you want some sense of mystery don't read below

****************************************

what happens:  as the candle burns the air the volume is reduced inside the glass which is now sealed with the puddle of water in the bottom.  This sucks water from around the bowl/dish up into the glass until the pressure is equaled.
 

paul.fr

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Re: What's your kitchen science?
« Reply #220 on: 31/01/2008 13:05:33 »
Excellent, Thank you Cameron. Now if the other 6,700 members could post one, just one, what a topic this would be.

what you need

Food colouring
A small jar, or Glass
A larger jar or glass
Aluminium Foil
Rubber Band or Selotape


what you do

Put cold water into the small glass or jar and add 5 drops or so of food coloring. Cover the mouth of the jar with aluminum foil and fasten it in place with a rubber band or tape. Use a pencil point to make a hole at the center of the foil. The hole should be 1/8 inch or so in diameter.
 
Fill a larger jar with warm water. Turn the small jar over and place the foil covered mouth just below the surface of the warm water. Tap on the bottom of the small jar. A ring of colored water will (should) travel downward through the warm water.

If you have a tall vase, then try substituting the larger jar for the vase. This will increase the time before the coloured ring hits the bottom, plus you can make a larger hole in the aluminium foil. Larger holes produce faster moving rings that quickly hit the jar's bottom.
 
Note: A dark coloured water soluble paint can be mixed with the water instead of food coloring.

Pictures to follow at the weekend...
 

paul.fr

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Re: What's your kitchen science?
« Reply #221 on: 15/02/2008 16:58:47 »
Here is one from the magazine Popular Science, attributed to chemist Tryggvi Emilsson

What you need


Microscope slide
Cover slip
Super glue
A sheet of black card
small artist's paint brush
Snow!



What you do


Go outside with some glass microscope slides, cover slips, and superglue (not the gel kind; it should be thin and watery).  Cover the slides and cover slips until they become as cold as the surrounding air. 

Let snow crystals fall onto a cardboard collection board, and scan around with a magnifier to find an attractive specimen.  Carefully pick the crystal up using a small artist's paintbrush and place it on one of the slides.


Place a drop of cold superglue on the crystal, and drop a cover slip on top.  Be careful not to melt or otherwise damage the snow crystal in the process.

Leave the slide outside or in your freezer for a week or two until the glue hardens.

Here is a picture of a snowflake using the above method. As you can see, there are some air bubbles, but practice does make better slides.



Alternative Method

Another method uses clear acrylic spray paint, which is readily available in hardware stores. The spray is especially effective for replicating windowpane frost and similar ice structures. The (cold) spray must be applied lightly, since the solvent in the spray can dissolve the ice if too much liquid is present.  The best procedure is to pre-coat the glass slide with the plastic film, place snow crystals on it, and then spray the surface again until the surface is moist.   The picture below is from Walter Tape, and was obtained by spraying over a crystal that was placed on a glass slide.

Topic Link:
How Do They Photograph Snowflakes ?
« Last Edit: 15/02/2008 21:40:25 by paul.fr »
 

paul.fr

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Re: What's your kitchen science?
« Reply #222 on: 15/02/2008 20:58:26 »
Is you area affected by acid rain? Lets find out...

What you need



2 finely chopped red cabbage leaves
distilled water
rainwater
a bowl
2 glass jars
a measuring jug
a sieve



What you do
 
Place the chopped cabbage leaves into the bowl and pour hot distilled water over them, let it stand for an hour. Use the sieve to strain the liquid from the cabbage leaves into a measuring jug. It should be a dark purple colour.
 
Pour 20ml of distilled water into one of the glass jars and 20ml of rainwater into the other, add some of the cabbage juice into the two jars making sure you put the same amount in each. The water will then change colour.
 
 
How does the colour of the water in the two jars compare? You should find that the distilled water stays the same, whereas the rainwater may change colour. It will turn red if the rainwater is acidic; the stronger the acid, the redder the water will become.
 
 

paul.fr

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Re: What's your kitchen science?
« Reply #223 on: 16/02/2008 14:51:34 »
What you need

A clear plastic container (size of shoebox)
red food coloring
ice cubes made with blue food coloring



What you do



Fill the plastic container two thirds full with lukewarm water, add a few drops of red food colouring and let the water sit for a minute or two.

Place a blue ice cube at one end of the plastic container.
Watch... what happens?


Explanation:

This is how a thunderstorm occurs. The blue and cold water sinks while the red and warm water rises. This happens because of convection. The blue water represents the cold air mass and the red water represents the warm, unstable air mass. A thunderstorm is caused by unstable air and convection plays an important part. A body of warm air is forced to rise by an approaching cold front therefore thunderstorm's form.

 

paul.fr

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Re: What's your kitchen science?
« Reply #224 on: 16/02/2008 15:21:17 »
What you need


2 tin cans with the labels removed (soup, baked beans etc...)
rock or table salt
crushed ice (or crushed, regular ice cubes)


What you do


Half fill one of the cans with the crushed ice, and add about 4 tablespoons of salt. Mix it well for about 30 seconds and then let sit.


In the other can put only crushed ice and cool tap water. Fill the can about half way full of ice and then put just enough tap water in the can to cover the ice.


Wait...

What happens?



Explanation:

you should notice frost forming on the outside of the can with the ice and salt mixture. Compare this with the liquid moisture on the outside of the can which contains ice only.


This is how both frost and dew form.

The salt wants to absorb water to make a salt solution. To do that, the salt has to melt the ice into water, melting the ice actually makes the mixture cooler. The salt water mixture inside the can gets below freezing, so the moisture from the air that collects on the outside of the can will freeze. This is why frost forms.
On the other can, dew forms because the mixture of the melting ice and water is just at freezing and the temperature outside the can is warmer causing the dew to form.

You can do this using two glasses, but the effect may not be as noticeable. You may also want to do this using ice cubes, that you have made, that have had food dye added to colour them.
Is the dew or frost that form the colour of the ice cubes, or is it white/clear?
 

The Naked Scientists Forum

Re: What's your kitchen science?
« Reply #224 on: 16/02/2008 15:21:17 »

 

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