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Offline Karen W.

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What's your kitchen science?
« Reply #275 on: 14/06/2008 06:28:51 »
That sounds like the same principal as the sugar cube experiment...Is it?? Kind of cool cause its in your mouth though!
 

paul.fr

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What's your kitchen science?
« Reply #276 on: 15/06/2008 15:42:21 »
That sounds like the same principal as the sugar cube experiment...Is it?? Kind of cool cause its in your mouth though!

Why don't you post it karen, then we can see.
 

Offline Karen W.

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What's your kitchen science?
« Reply #277 on: 17/06/2008 08:42:05 »
I do believe it was your experiment from the start of this thread... The one where you go into a very dark room with sugar cubes and a pair of pliers. You wait for I think you said two minutes and then your eyes have adjusted to the light.. then you begin breaking the sugar cubes with the pliers.. I believe this is the one we sent home with the kids who were afraid to stay in the dark to see it. We hoped they would be less scared to do it with their folks! LOL
 

paul.fr

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What's your kitchen science?
« Reply #278 on: 18/06/2008 16:57:08 »
Karen, you are correct but i don't think i did that one, i think it was done by Dave on the show with a pair of plyers. Then again i do not have the memory of a goldfish!
 

paul.fr

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What's your kitchen science?
« Reply #279 on: 18/06/2008 16:58:37 »
What you need

Two (glass) milk bottles
matches or lighter
a piece of thick cord or shoe lace a few inches long


What you do

Put one of the milk bottles in the fridge for 10 minutes or so and the other bottle in a pan of very hot water.
After the time is up, Take the cord, light one end and drop it in to the cold bottle. Now turn the warm bottle upside down and place it on top of the cold bottle. Both bottles should have their open end joining.

What happens?

Now turn the bottles upside down.

What happens?


Explanation

First off, the smoke from the lit cord should have remained in the cold (bottom) bottle. When you turned the bottles upside down the smoke should have dropped in to the bottom bottle, but why?

In the first instance the smoke is held down by the heavy cold air, then when you turn the bottles upside down the cold and heavier air drops down in to the bottom bottle and again keeps the smoke there. The warm air is push up in to the top bottle because warm air is lighter.

Please use caution around matches and hot water.
 

Offline Karen W.

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What's your kitchen science?
« Reply #280 on: 19/06/2008 18:34:04 »
Karen, you are correct but i don't think i did that one, i think it was done by Dave on the show with a pair of plyers. Then again i do not have the memory of a goldfish!

Thanks Paul.. I know I got it off here!LOL
 

Offline Karen W.

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What's your kitchen science?
« Reply #281 on: 20/06/2008 12:04:16 »
Here is a slime recipe we have used at the preschool. We got it from the internet way back.. but I do not have the site..(Sorry) Its fun stuff Kids and adults alike like it! try the options they are cool too!

Try this one:

SLIME RECIPE

1/4 cup White Glue
1 1/4 cup Water, divided
1 tbsp. Borax - found in the laundry detergent aisle of your grocery store
Food Coloring

Borax is available in the laundry section of your local grocery store. Add 1 tbsp. Borax to one cup of warm water. Stir until completely dissolved.

Make a 50% water 50% white glue solution. Take 1/4 cup of each and mix thoroughly.

In a ziploc bag, add equal parts of the borax solution to equal parts of the glue solution. (Half cup of each will make a cup of slime.)

Add a couple drops of food coloring. Seal bag and knead the mixture.

If slime is too sticky, add a little more borax. If slime is too slippery, add a little more white glue solution.

Variations:

Less rubbery & more transparent slime: Try a 4% solution of polyvinyl alcohol instead of the glue mixture.

Different Consistencies: Add shaving cream or baby powder to the mixture

Glow in the Dark Slime: Add several drops of glow-in-the-dark paint during mixing.



 

paul.fr

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What's your kitchen science?
« Reply #282 on: 23/06/2008 09:13:16 »
What you need

Cloth bag or a non-transparent container
Marker pen
Notepad
Calculator (optional)
Template of ‘Forty Fine Fish'
Coloured card or paper
Scissors
A friend

What you do

Draw and cut out 'Forty Fine Fish', preferably on coloured card.

Ask your friend to secretly count out a number of fish tokens and place them into the container or bag. To make it more of a challenge, ask them to make it any number higher than 20.

Now it's time to go fishing. To get an estimate of the number of fish, you need to do several fishing trips:

    * On your first trip, pull ten fish out of the container and 'tag' them with a cross using your marker pen before returning them
    * On your second trip, shake the container then pull out another ten fish without looking. Count how many of those fish are marked with the cross and write down the number, then return them to the container and mix them up
    * Now go fishing a third time, again recording the number of fish with crosses and returning them to the bag, mixing again
    * Go fishing one last time, writing down the number of fish you catch with crosses.

Add these 3 numbers and divide the result by 3 to get an average result. For example, if you counted 5 with crosses, then 3, and then 4, this equals 12. 12 divided by 3 equals 4.

The equation which estimates the total number of fish in the bag is:

    (Total number caught the first time x total number caught the second time) / average number caught with a cross

In our example, this would be (10 x 10) / 4. This equals 25, which is our total estimate.

Ask your friend for the actual number. Is your estimate close?


What's happening?

Estimates are guesses based on a small amount of information. Obviously we can't know the exact number of fish in a large area like a lake, so we need some way of getting a small amount of information and then making a guess based on it.

When you go fishing, you are taking a ‘sample' of the larger population. Samples usually represent the population you want to know more about. For example, half of a school might be boys and half girls. If you took a sample of the school, such as one class of students, it should also have about half boys and half girls. If you wanted your estimate to be more accurate, you could count two classes instead to get more numbers.

Your first fishing trip took one sample, and then tagged them all as caught. The second fishing trip counted the same number you caught the first time and compared it with the number of new (untagged) fish being caught. Obviously, if there aren't a lot of fish, you'll catch most of them again. But if there are large numbers of fish in the lake, you mightn't catch any tagged fish at all the second time.

Mark-and-recapture, also called tag-and-release, is a way of using samples to estimate the size of a population when you can't possibly count them all any other way.


Applications

Many organisms don't sit still long enough to be counted. People aren't all that different –it's difficult to study all of the people in a large area, which is why we do surveys. This means we study a small 'sample' part of a large number of people to provide us with an example of what other people might do as well.

We must be careful that our sample is similar to the whole population we want to study. Would it be accurate to study what breakfast cereal most people prefer if we only asked toddlers? Or what television shows all ages watch by only asking parents? Such is the case with our fish – it is only accurate if we can catch all types of fish we want to count. Imagine catching the fish using a net with holes big enough to let smaller fish through. Would this give us an accurate estimate?

"borrowed" from CSIRO.
either cut your own fish shapes out or use this template:
http://www.csiro.au/helix/sciencemail/activities/images/FortyFineFish.pdf
« Last Edit: 23/06/2008 09:31:15 by Paul. »
 

paul.fr

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What's your kitchen science?
« Reply #283 on: 25/06/2008 19:28:54 »
What you need   


2 short glasses of water
A pie plate or tray
Liquid dish soap


What To Do

Put the first glass of water in the center of the pie plate, then slowly pour some water from the second glass into the first glass until it is very full and the water forms a dome above the rim of the first glass. Set the glass with less water aside.

Carefully stick your finger straight down through the dome of the water in the full glass and watch what happens.
Then put a small drop of dish soap on the tip of your finger and do the exact same thing - stick the finger with soap on it straight down through the dome of water.

what happens this time?


Explanation

Water is made up of lots of tiny molecules. The molecules are attracted to each other and stick together. The molecules on the very top of the water stick together very closely to make a force called surface tension. Surface tension is what caused the water to rise up above the rim of the glass in the experiment - the water molecules stuck together to make a dome instead of spilling over the side. Why didn't the dome break when you stuck your finger through it? Why didn't the water spill over the glass? Well, the surface tension was strong enough that it just went around your finger. The water molecules still stuck to each other and nothing spilled! What happened when you put your soapy finger into the water? The soap on your finger broke the water's surface tension and some of the water molecules didn't stick to each other any more and they were pushed out of the glass!

The force of surface tension also creates bubbles. In plain water, the surface tension is strong and the water might make some bubbles, but they will not last very long and they will be very small, because the other molecules in the water will pull on the bubbles and flatten them. Soap needs to be mixed with the water to make bubbles that can float through the air. When you add soap, the water becomes flexible, sort of like elastic, and it can hold the shape of a bubble when air is blown into it.
 

paul.fr

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What's your kitchen science?
« Reply #284 on: 26/06/2008 09:21:02 »
What You Need

Liquid dish soap
Distilled water (tap water is okay, but distilled water makes the best bubbles)
2 clean containers with lids
glycerin or light corn syrup
Measuring cup
Mixing spoon
A plastic pipet (cut off the closed end to make a bubble blower) or a drinking straw
Tape and a marker


What you Do



Homemade bubble blowerMeasure 6 cups of water into one container, then pour 1 cup of dish soap into the water and slowly stir it until the soap is mixed in. Try not to let foam or bubbles form while you stir.
Once the soap and water are mixed, go outside to test it. Dip the cut end of your bubble blower into the solution and let the extra drip off. Blow through the narrow end to make bubbles. Do you get a lot of bubbles? How big are they? How long do they last before they pop?

pour half of the bubble solution into the other container. Put a piece of tape on the outside of the new container. Use the marker to label it "Super Bubbles."
Measure 1 tablespoon of glycerin or 1/4 cup of corn syrup and add it to the "Super Bubbles" container. Stir the solution until it is mixed together.
Dip your blower or straw into the new bubble solution and blow. Are these bubbles different from the plain soap and water bubbles? Are they bigger or smaller? Do they last longer or pop faster? Can you blow a really big bubble?

To make even better bubbles, put the lid on the container and let your super bubble solution sit overnight. You can add glycerin or corn syrup to the other container to make those bubbles better, too. (Note: If you used "Ultra" dish soap, double the amount of glycerin or corn syrup.).


Explanation

The first bubble solution was just soap and water. As you learned from the Surface Tension experiment (above), soap helps bubbles form. You probably got some small bubbles that didn't last very long from the soap and water. Then you added glycerin or corn syrup to the soap and water and probably noticed that the bubbles you blew were stronger and better than before. Did they last longer? Were they bigger? The glycerin or corn syrup mixes with the soap to make it thicker. When the water that is trapped between the layers of soap in a bubble evaporates (or dries up), the bubble will pop! The thicker skin of the glycerin bubble keeps the water from evaporating as quickly. You can probably also blow a much bigger bubble with the second bubble solution that you made than with the plain soap and water one. Adding glycerin or corn syrup makes bubbles stronger and helps them last longer. It makes super bubbles! 
 

paul.fr

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What's your kitchen science?
« Reply #285 on: 27/06/2008 14:04:49 »
What you need


the above bubble solution
the lid from the container
a straw
some objects with pointed ends.



What you do


Set the lid on the table so that the part with the lip is facing up. Fill the lid with bubble solution. Dip your straw into the bubble solution container so that it is wet half way up the straw. Touch the straw to the
lid and blow a bubble on the lid. Slowly pull the straw all the way out of the bubble.

Now dip the pointed end of your scissors (or any pointy object) into the container of bubble solution. Make sure they are completely wet. Poke the scissors through the wall of your bubble. Watch what happens. Try it again with other pointed objects, just make sure anything you touch to the bubble is wet. Can you stick your finger through the bubble?



What's Happening?


Stick an object through a bubble!You should have been able to push the scissors through the wall of the bubble without popping it! When something wet touches a bubble, it doesn't poke a hole in the wall of the bubble, it just slides through and the bubble forms right around it. The bubble solution on the scissors filled in the hole that would have been made. If you try poking dry scissors through your bubble, you will see it pop instantly! (If it popped when you put the wet scissors in, something was probably too dry. Try it again and make sure anything that touches the bubble is completely wet with bubble solution.) For another trick, get one hand completely wet in the bubble solution then use the other hand to hold your bubble blower and blow a big bubble in the palm of your wet hand.
 

paul.fr

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What's your kitchen science?
« Reply #286 on: 28/06/2008 01:20:00 »
If you take two sheets of clear glass or plastic separated by about one-half inch, soak them in soapy solution and then blow bubbles between the sheets, you will get many bubble walls. If you look closely, you will notice that all of the vertices where three bubble walls meet (and there are always three,) form 120 degree angles. If your bubbles are of uniform size, you will notice that the cells form hexagons and start to look much like the cells of a beehive. Bees, like bubbles, try to be as efficient as possible when making the comb. They want to use the minimum possible amount of wax to get the job done. Hexagonal cells are the ticket.



When one bubble meets with another, the resulting union is always one of total sharing and compromise. Since bubbles always try to minimize surface area two bubbles will merge to share a common wall. If the bubbles are the same size as the bubbles to the left, this wall will be flat. If the bubbles are different sized, the smaller bubble, which always has a higher internal pressure, will bulge into the larger bubble.



Regardless of their relative sizes, the bubbles will meet the common wall at an angle of 120 degrees. All three bubbles meet at the center at an angle of 120 degrees. Although the mathematics to prove this are beyond me, the 120 degree rule always holds, even with complex bubble collections like a foam

 

paul.fr

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What's your kitchen science?
« Reply #287 on: 28/06/2008 01:33:19 »
some bubble facts.

What Are Bubbles?

Bubbles are pockets of soap and water that are filled with air. When soap and water are mixed together and air is blown into the mixture, the soap forms a thin skin or wall and traps the air, creating a bubble. Soap bubbles are not the only kind of bubbles. You can find bubbles in lots of liquids. You might see small bubbles in plain water, but they will always be in the water, or floating on the surface of the water, not floating through the air. There are bubbles in soda pop, too. The special thing about soap bubbles is that they can float freely in the air; they don't have to be touching water or another liquid like most bubbles do. Can you find other bubbles around your house? What about something that is round and filled with air like a bubble? (Some examples are balls, balloons, and bubble wrap.)

How does soap help make bubbles out of water? Soap makes the surface tension of water weaker than normal. It also forms a very thin skin that is more flexible than water. When air gets trapped under the surface of the mixture of soap and water, the flexible skin stretches into a sphere shape (round like a ball), making a bubble! You can see the flexible skin that forms a bubble by dipping a bubble wand into some bubble solution. When you pull it out, the hole will be filled with a stretchable skin of liquid. If you blow gently on the skin, you'll blow a bubble!

What Happens to Bubbles?

Since bubbles are made from soap and water, they can only last as long as the water lasts. In dry air, water evaporates - it is soaked up by the dry air around the bubble and the skin of the bubble gets thinner and thinner until it finally pops! Evaporation isn't the only thing that pops bubbles. Anything dry can pop them. When a bubble floats through the air and lands on your finger, on a blade of dry grass, the wall of your house, or your pet's fur, the bubble will pop. When something sharp and dry touches the bubble, it pokes a hole in the bubble's skin, all the air goes out of it, and the bubble disappears! To learn how to touch a bubble without popping it, do Trick 2 in the Bubble Tricks experiment.

Why Are Bubbles Round?

Bubbles that float in the air and are not attached to anything are always round because the thin wall of soap is pulling in while the air inside of it is pushing out. A bubble always tries to take up the smallest amount of space and hold the most air that it possibly can. A sphere, the round ball-shape of a bubble, is the best way to take up a little space and hold a lot of air. Even when a bubble starts out as a square or another shape, like in Trick 1 from the Bubble Tricks experiment, it will always turn into a round sphere as soon as it floats away into the air. A square bubble would take up more space than a round one.

Lots of bubblesThere are a few times when bubbles are not round. Sometimes the wind blows them into different shapes. When bubbles are surrounded by lots of other bubbles, the ones in the middle get squished into other shapes, like squares or hexagons (shapes with six sides). Try blowing a lot of bubbles right next to each other in a shallow container and see if there are any that are not round. If you pop the bubbles on the outside, the ones on the inside will not be squished anymore and they will push back out to round bubbles again!
 

Offline Andrew K Fletcher

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What's your kitchen science?
« Reply #288 on: 30/06/2008 09:01:53 »
Comments welcomed.
Video

What You Need:

2 litres of water 2 kilos of granulated sugar, large saucepan and supervision is a must because boiling anything on a cooker is dangerous and boiling syrup will cause severe burns if it comes in contact with the skin.

Scale down to 1 k of sugar and 1 litre of water in a smaller pan.

Add water and all of the sugar to the saucepan and begin to heat it.

Observe closely how the denser fluid at the bottom of the pan behaves as the heat begins to motivate the syrup. At the same time observe the vapour bubbles and the rapidly agitating syrup below the surface.

Adding heat to the water and sugar crystals accelerates the dissolving of the sugar creating a very dense solution. The surface of the syrup does not boil, yet below the surface about half way down the saucepan is clearly boiling and if you look very close you can see lots of large and small gas bubbles forming and rising as you would expect them to do. However if you study what is happening you will see that the surface of the syrup remains unbroken and shows little if any motion while below the surface it is completely different and actively bubbling and boiling.

So what do you think is happening?

I suspect that a flow and return circulation is operating in the lower active level of the syrup where the heat is causing the fluid to form gas and rise but in doing so is generating a return flow from the cooler water causing the rotation of the syrup rather than it reaching the surface and disrupting the stagnant state. The dense syrup is acted upon by gravity and the heat at the base of the pan changes the density of the syrup causing it to rise, where it meets the lower part of the cooler surface less dense syrup and returns back to the base of the pan taking with it the vapour bubbles and preventing them from reaching the surface of the liquid.

Before all of the sugar has turned into clear liquid stir the solution with a wooden spoon and let it return back to the un-agitated state and you should see the lower level behave as before and the surface layer remain once again still.

Eventually the surface syrup heats up and the liquid boils as one would expect a liquid to boil. Yet when another Kilo of sugar is added to the now boiling syrup the same low surface flow happens again and the surface of the liquid stagnates until all the sugar has dissolved and the liquid is boiling in the normal manor.

This is a fascinating experiment that requires supervision as boiling syrup is very dangerous. The sugar looks like clouds viewed from an aircraft for a while.

What does it tell us?

Having been working on a density flow theory in plants, trees, animals and humans that generates circulation by density changes occurring in the fluids due to evaporation, the boiling syrup experiment shows how powerful this gravity driven flow really is. It also shows how density changes at the surface of the ocean due to evaporation and the resulting increases in density of surface water generate an underwater river that drives the Atlantic Conveyor system, a river thought to be larger than all of the combined rivers in the world that powers the world’s weather.

But does it also tell us something about the nature of gravity?

Andrew K Fletcher

You may also be interested in my other density videos on You Tube and if you like them please leave a comment and rate them :)
 

paul.fr

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What's your kitchen science?
« Reply #289 on: 03/07/2008 16:41:18 »
What you need


a key
a saucer or plastic bowl large enough to contain the silver object
a cardboard box large enough to cover the silver object
Something made of silver or something silver plated.  It should be something that is easy to polish, as you will have to polish it twice.  Flat surfaces work much better, so a spoon or knife will work very well. The experiment will not damage the silver, but I suggest that you avoid ornate pieces with lots of hard to polish areas.
Tincture of Iodine (with the medical supplies at your local store) 


What you do


Polish the silver until it is very shiny.  In a dimly lighted area, place the silver object on a saucer or in a plastic bowl.  Carefully pour some iodine over the silver and then cover it with a box, to keep out as much light as possible.  Wait for about two minutes.

Remove the cover and shine a very bright light, such as a bright lamp onto the silver.  Hold the light there for about four minutes.  Then remove the bright light and rinse the iodine from the key and the silver.  Remove the key and look at the surface of the silver.  You will see the image of the key.

Polishing will remove the resultant tarnish from the silver, with no harm done.


Explanation:


The iodine reacted with the silver to form a chemical called silver iodide.  Silver iodide is sensitive to light.  In bright light, it change into silver oxide, a dark colored chemical.  That reaction does not happen under the key, where the light does not reach, so that part of the silve stays light colored.  Together, this produces a negative image of the key.

This is basically the same thing that happens in a photograph.  The parts of the film that are hit by light are changed, while the parts that remain in the dark are not.  This produces a negative image.  Shining a light through the negative onto treated paper gives you a negative image of the negative, in other words a positive image.

Warning!  Iodine is toxic and will stain skin and clothing.
 

Offline neilep

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What's your kitchen science?
« Reply #290 on: 03/07/2008 18:19:42 »
BEND WATER

What You Need:
(go on...go and get this...beware..some combs bite !)

    * comb
    * a piece of wool, nylon or fur

What you do:....do it....do it now !!

Rub a comb quickly against the piece of wool, nylon or fur for about a minute

Hold the comb near a trickle of water from a faucet.

What Should happen:

The charged comb should attract the water toward it.



Why does this happen?
(I'll tell ya shall I ?...yes..yes I will !)

 By rubbing the comb, you’re covering it with little negative charges. The negative charges are attracted to the positive charges against the water.




Warning: Water may inadvertently splash on ewe...and if ewe're like me..(who bathes just once a year)...then you must be warned that a part of you may accidentally become clean !!
« Last Edit: 03/07/2008 18:22:00 by neilep »
 

paul.fr

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What's your kitchen science?
« Reply #291 on: 04/07/2008 22:54:08 »
What you need


Portable ultraviolet light
Bottle of tonic water (unopened)
Drinking glass, clear
Darkened room


What you do


Open the tonic water and pour some into a large, clear drinking glass. Place a white sheet or poster board behind the glass to create a white background. Turn off all the lights and completely darken the room. Turn on the black light and shine it on the tonic water.

what happened?


Explanation

The black light gives off UV light which is a higher energy light than visible light and the human eye is not able to see it well. So, if ultraviolet light is virtually invisible, how can the tonic water glow so brightly? The tonic water's color under the UV black light is fluorescent-blue because it contains quinine, a substance that changes when it absorbs UV light. When the black light shines on the tonic water, the tonic water absorbs the light and excites the electrons. Since the electrons naturally want to return to their original relaxed state, they give off energy that has a wavelength in the blue part of the visible spectrum. That's why the tonic water has an eerie blue glow in the presence of ultraviolet light!
 

Anastasia.fr.1

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What's your kitchen science?
« Reply #292 on: 05/07/2008 18:59:27 »
What you need

A piece of paper
A pencil
A drinking glass.
A jug of water.


What you do


Fold the sheet of paper in half and draw an arrow in the middle of one side.

Stand the folded paper on a table with the arrow pointing left. place the empty glass in frount of it. now fill the glass with water. now slowly move the piece of paper away from the glass, you should be looking though the glass as you do this.

what happens to the arrow [?] [?] [?]

I dont know why this happens but grahem does [8D]
 http://www.thenakedscientists.com/forum/index.php?topic=15658.0

By  Anastasia-marie
 

Anastasia.fr.1

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What's your kitchen science?
« Reply #293 on: 05/07/2008 20:57:43 »
It's not a science experiment, but it's fun to do.

think of a number 1-10
double it
add 14
divide by 2
take away the first number you thought of

i bet your left with the number 7

MAGIC MAGIC
by Anastasia
 

Anastasia.fr.1

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What's your kitchen science?
« Reply #294 on: 06/07/2008 10:32:17 »
You will need


Template
Photocopier (optional)
Large sheet of card – the bigger the better
Cutting blade or scissors
Ruler
Coloured card, pens and pencils
Glue and/or sticky tape


What to do
Download this Template
 and print it out.

The bigger the model is, the better the illusion works. There are two ways you can make the template bigger if you wish:

Use a photocopier to blow the image up onto one or more sheets of A3 paper.
Measure the lines on the template and multiply them all by the same number to come up with a larger scale diagram. Use a protractor to measure the angles of each part of the template. Use a ruler to draw this new template onto your card.
Cut out the template, then trace it onto the card.

Notice that one panel is decorated with a distorted chequered pattern – use pens or coloured card to copy this pattern as precisely as possible, or better yet, cut the pattern out of the template paper and glue it in place onto the card.

Decorate the rest of the panels as if it is a room, paying attention to how one end of each panel is narrower than the other end. So, if you draw a window or a picture, it must also have one end narrower than the other.

Cut the model out of the card. Remember to also cut out the two shapes labelled ‘x’; one is so you can reach into the model, and the smaller hole is for you to look into the model.

Fold the model into a box shape and glue or tape the tabs in place on the outside.

Take two small objects roughly the same size (e.g. two toy cars) and place one in each corner of the box opposite the small hole.

Peek through the hole. How do the objects look?

What’s happening?


This model is called an ‘Ames room’, named after the ophthalmologist Adelbert Ames who first created one. If the model is neat enough, the room should look fairly normal when peering through the hole. One of the objects should look smaller than the other, however, even though they are the same size.

We use a number of clues in our visual field to determine the size of an object. For example, the slightly different positions of our two eyes on the front of our heads mean each eye sees a slightly different picture. Combined, these two images give objects depth, but can also give clues about how far away they are.

A more important clue, however, comes from the assumptions our brain makes about the room. It is difficult for your brain to tell whether the far wall is perpendicular (at right angles) to your line of sight, or slanted away. However, there is a rule your brain is familiar with – two straight lines coming together to a point indicates distance. Think about how the parallel lines of a railway track seem to converge in the distance.

Using that rule, your brain determines the room is ‘normal’, which means both objects are the same distance away when they really aren’t. The conclusion it comes to? One object is actually smaller and close by rather than far off in the distance.

Applications


Ever wondered how Gandalf was made to look so much bigger than the hobbits in The Lord of the Rings? No, they’re not using shorter or taller actors – they are all roughly the same height in real life. While computer effects could be used, this can be expensive.

A cheaper method for film makers is to use effects such as those used in the Ames room to make things seem bigger or smaller. While the set looks normal on film, in real life it has been built using odd angles. When one actor stands on one side of the room with another actor opposite them, they look as if they are standing side-by-side, where really one is standing further in the distance, making them look small.

written by CSIRO.

 

paul.fr

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What's your kitchen science?
« Reply #295 on: 10/07/2008 14:20:07 »
What you need


a pie pan or shallow bowl
a candle
a glass jar large enough to hold the lit candle
water

 
What you do


Light the candle and let a few drops of melted wax fall on the middle of the pan.  Place the bottom of the candle into this wax to secure it in place.  Carefully add about an inch of water to the pan.  Relight the candle if it has gone out, and place the jar over it.  Watch carefully.  After a minute or so, the candle will go out, and the water will rise up into the jar.

 
Explanation

This shows that the candle has burned up the oxygen, and the water has risen into the jar to take its place, right?  WRONG!!!!!   If you watch carefully, you will see why is it wrong.  When you first place the jar over the candle, air bubbles OUT of the jar.  If you are slow about placing the jar over the candle, you might not notice this, but if you cover the candle in one quick motion, you will see the air bubbling out.   Once the candle goes out, the water begins to rise in jar. 

 
Now, lets think about that.  If the water was rising because the oxygen was burned up, it would rise while the candle was burning and stop as soon as the flame went out.  Is that what you saw?  No.  Then what really did happen?

 
As the candle burns, it is heating the air in the jar, causing it to expand.  This causes the bubbles that leave the jar.  The candle is burning oxygen, but the oxygen does not vanish.  It combines with carbon from the burning wax to form carbon dioxide, another gas that also takes up space. 

 
When the candle goes out, the air begins to cool, which causes it to contract.  As the air gets smaller, the water rises into the jar. 

Written by Robert Krampf
 

 

paul.fr

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What's your kitchen science?
« Reply #296 on: 20/07/2008 15:55:23 »
What you need


Tap water
A glass or clear beaker


What you do

Fill the glass with tap water and put it somewhere it will not be disturbed, go to bed and examine the glass in the morning.
What happened?


Explanation:

You should have noticed that the water in the glass had bubbles, the bubbles should be on the side of the glass. But how did the bubbles get in to still tap water?
Well I have no idea, but luckilly for us, Ian does know.
Where did the bubbles come from in my glass of water?
 

paul.fr

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What's your kitchen science?
« Reply #297 on: 23/07/2008 15:42:59 »
What You need


A4 sheet of paper
Scissors
Sticky tape


What you do


Fold the A4 paper lengthways into thirds. Use the creases to neatly cut one-third of the sheet away. You will be left with a sheet that is now two-thirds the original size and creased into halves.

Take one of the long edges of the sheet and make a fold about 1 cm wide. Run a fingernail along the crease to press it down firmly.

Repeat this process, folding the edge over four or five times, until you reach the middle crease.

Turn the sheet over and grip the shorter ends of the sheet, with one end in each hand. Find the edge of a desk or the back of a chair, and rub the folded side of the sheet back and forth over the edge. After a few rubs, you’ll notice the sheet will start to curl.

Continue to roll the sheet into a circle, tucking one edge into the fold of the other. Use sticky tape to secure the edges into place.

To throw: pick up the tube as if it is a can of soft drink, with the folded side at the bottom. Find a large, open space and aim the folded side of the tube in the direction you want the tube to fly. Swing your arm back and throw it.

Do it again, this time remembering to spin it with your fingers as you release it.

With practice, your paper ring should fly quite a long distance.

Explanation:


The paper ring flies for much the same reason a normal paper plane does.

Many forces come into play – thrust (propelling the plane forward) is opposed by drag (the resistance of the paper against the surrounding air). Throwing the ring gives it thrust.

There is also gravity pulling the plane’s mass down. But, the ring doesn’t fall because the shape of the wing is special – as air flows close to the surface, some of it is slowed down by the resistance against the wing. As this happens differently on the outside than it does on the inside, it creates a difference in how the air pushes against the paper on each side. This is called ‘lift’, and helps increase the force under the ring which keeps it from falling due to gravity…at least until the thrust runs out.

One reason the ring eventually falls is because of its unstable flight path. The ring will naturally want twist away from where you throw it, which takes away some of its thrust. By spinning it, you give the paper ‘angular momentum’. It acts like a gyroscope, making it more stable as it flies and allowing it to get more out of the thrust.
 

Offline neilep

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What's your kitchen science?
« Reply #298 on: 08/09/2008 20:29:31 »
Posted this as a genuine question but it also serves as a contribution to the FANTASTIC thread !

Dear Peeps Who Sing This !

"Roll me over lay me down and do it again
Roll me over in the clover, roll me over lay me down and do it again"


As a sheepy, I of course indulge in consuming fizzy drinks !


See my fizzy can of pop ?



Hmmm...what delicious treat resides inside I wonder ?

Now then, If I take another one....shake it hard and then place both of them at the top of a slight incline...the shaken one will roll down slower !!


Why's that then ? Why does the non shaken one roll faster ?


I don't know.. I simply do not have a freaking clue !!

Oh how I wish I knew !...will someone who knows this tell me ?

Thanks

Hugs and shmishes


Neil
Soda Pop Problem Asker

xxxxxxxxxxxxxxxxxxxxxxxxxxxx

mwah mwah mwah mwah !!!
 

Offline Cameron Lapworth

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What's your kitchen science?
« Reply #299 on: 09/09/2008 01:38:21 »
Hi,
   Another one I've done with my year 8's in science is building an electric motor with a magnet battery and some cardboard and a coil of wire. very impressive you can really get some speed up.  I've found a link to something similar  here.  try it it's great.  newbielink:http://www.pbs.org/weta/roughscience/discover/powerplant.html#motor [nonactive]

Cameron
 

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What's your kitchen science?
« Reply #299 on: 09/09/2008 01:38:21 »

 

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