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Will it Centrifuge? (part 3 - the Club Edition.)

last photo ←

It had to happen.

My science clubbers got wind of the centrifuge's existence, and demanded to have a go with their own samples. Some of them made their own mixtures, just to see if they could be separated by sheer force of gravity.

The samples got spun up in batches of four:

Batch 1:

Hair gel mixed with pure blackcurrant juice (yellow tube)
Mud, water, pencil shavings and washing up liquid (blue tube)
Brown sauce (it's a British condiment) (orange tube)
Salad cream (light pink tube)

Batch 2:

Flour mixed with green food colouring, washing up liquid, water and rice mixed with blue food colouring. (green tube)
Strawberry jam (with bits) (dark pink tube)
Flour, water and green food colouring (orange tube)
Raspberry jam (no bits) (light pink tube)

Batch 3:

"American hot dog mustard" (yellow tube)
Melted Margarine (blue tube) (melted by floating tube in hot water for a couple of minutes)
Crunchy peanut butter (orange tube)
Rice, water and blue food colouring (green tube)

I've posted each sample as "before" and "after", to make the changes (where they occur) more obvious.

The shot of the inside of the centrifuge shows a thin beige line - the clubber who filled the peanut butter tube didn't clean the outside of the tube properly, and slowing from 13,000rpm to stationary in a few centimetres mashed the debris evenly around the centrifuge's innards. Fortunately it wiped off easily.

Watch out for the margarine...

Need some backgound?
Part One
Part Two - Blood!
Original Forum Thread

And a "How To" Instructable is in the pipeline, I'm just waiting for some information.

52 comments

1-40 of 52

Jun 12, 2009. 11:12 AMzoltzerino says:

Rather than separating mixtures, could you try compounds perhaps? Your school seems to have a rather flash science dept. ZZZZ

May 25, 2009. 5:53 PMPortalForce says:

Wow! This machine is cool! I really love the experiments you are doing! I was just wondering where can you get it? And how much will it cost in Canadian money? I wonder what happens if you put Non-Newtonian Fluid (Oobleck) in the microfuge? I want you to try it, you don't have to, but I wish you did. Thanks,

142

May 30, 2009. 11:33 AM

Kiteman (author) says:

I got it for free, donated to the school through a government scheme, but you could try here.

Jan 27, 2009. 12:01 AMnfitz says:

As you showed in p1 you're trying to run a 13k rpm centrifuge with a 12w (12v 1A) power supply. I bet its doing < 2 krpm. Give it more AMPS.

142

Jan 27, 2009. 10:20 AM

Kiteman (author) says:

It's the power supply recommended by the manufacturer.

Jan 27, 2009. 7:49 PMnfitz says:

ok , just a suggestion. No harm will come of trying a bigger psu at the same voltage. Good writeup.

Aug 27, 2008. 2:01 PMSunny124613 says:

ew i wouldn't try urine... but maybe is you try fatty yogurt or maybe some mayonaise

May 17, 2008. 10:38 AMdarth2o says:

Urine, try urine!

Aug 15, 2008. 10:51 PMJames (pseudo-geek) says:

urine for 1 hour at top speed would be interesting.

Jul 31, 2008. 8:52 PMstruckbyanarrow says:

try soda please! 4.5 stars!

Jul 16, 2008. 3:09 PM

whatsisface says:

You have to do a tiny martini in this. That's an order.

Jul 8, 2008. 7:12 PMSunny124613 says:

I have never seen an instructable like this before! Anyways it is GREAT!!!

142

Jul 9, 2008. 9:51 AM

Kiteman (author) says:

Thank you, I try my best.

May 16, 2008. 7:05 PMClayton H. says:

How much would one of them fancy "centrifuges" cost and were can I receive one?

142

May 17, 2008. 3:17 AM

Kiteman (author) says:

Most lab centrifuges cost upwards of 150GBP. The one I have is a "Millennium Product" - for some reason, the university-based team that came up with them sent lots to schools for free. They can also be purchased for around 80GBP+taxes - follow the links I gave in the text to find the details.

May 22, 2008. 3:12 PMItsTheHobbs says:

How about American dollars? I want to see if I have enough.

142

May 23, 2008. 9:37 AM

Kiteman (author) says:

Probably about $150, plus various taxes and shipping from this link.

May 23, 2008. 1:48 PMItsTheHobbs says:

Oh, ok. not enough....

May 17, 2008. 10:39 PM

Zorink says:

My dad got one for me a few years ago from the hospital he works at. They got new ones and were just going to throw the old ones out! Testing random stuff in it can be surprisingly entertaining. Blood is the most interesting thing we ever put in it. My diabetic friend came over and he used his finger pricker thing to get some of his. After an hour the top 60-80% was a yellow/clear (plasma), the bottom was a deep red (blood cells), and the very tip was black/gray(platelets and other stuff).

May 18, 2008. 1:37 PMjackfr0st says:

these are wonderful macro pictures!...and what are the layers in the margerine? and what are the size of the centerfuge "capsules"?

142

May 18, 2008. 1:42 PM

Kiteman (author) says:

Actually, those photos were a pig to take - for some reason my camera refused to focus on the tubes. I think it's the lack of contrast. I had to put my finger beside them, focus on my finger and then move my finger. The layers will be fats and water (there's a lot of water in margarine). The tubes are 1.5ml - about 1/4 of a teaspoon full.

May 21, 2008. 3:43 PM

Goodhart says:

I wonder if using white or black paper, split in half with each half on one side of the tube, would have helped....or something like that.

May 21, 2008. 11:25 AM

Goodhart says:

I just found out that some portion of the Chocolate making process involves a centrifuge. :-)

May 21, 2008. 11:26 AM

Goodhart says:

article in the newest MAKE: Timothy and the Chocolate factory....

142

May 21, 2008. 2:09 PM

Kiteman (author) says:

Hah, just typical...

May 21, 2008. 3:42 PM

Goodhart says:

It is only mentioned in the article....I didn't give away what it is mostly about :-)

May 21, 2008. 3:01 PMHazardRush says:

Maybe someone has mentioned it already, but how about Ferrofluid, or Magnaview Fluid? my bottle says magnets permanently suspended in oil. lets see if that really means "permanently". Also try brewed coffee.

142

May 21, 2008. 3:24 PM

Kiteman (author) says:

Hmmm, coffee would be appropriate.

May 18, 2008. 1:11 PMGorillazMiko says:

*sigh* I'm realizing a lot of other members are receiving "The Power" to feature.

Time to go look for part 2.

(+5/5 stars)

May 18, 2008. 1:29 AMalexhalford says:

How fast does a centrifuge spin? I ask because I have a vacuum cleaner motor that I have yet to find a decent use for...

142

May 18, 2008. 1:37 AM

Kiteman (author) says:

This one goes up to 13,000rpm, depending on the input voltage.

Others are slower, others are faster, but the g-forces are a combination of the radius and the revs. Double the diameter of the device (at the same revs) and you will double the g-forces, but double the revs, and the forces go up four-fold.

May 18, 2008. 10:23 AMalexhalford says:

And also, could I use a regular 555 astable oscillator with PWM to control the speed of an ac motor or would that only work with dc motors? So basically this circuit (see attached) with it's output going to the gate of a MOSFET. The MOSFET will then be the switch in the AC power cable. Would this work? Thanks for your help. AlexHalford

142

May 18, 2008. 10:34 AM

Kiteman (author) says:

I think that circuit would behave quite differently - IC2 is specifically labelled with + and -, plus capacitors behave quite differently in an AC circuit.

_{And that circuit is only rated for 9V, not 120V or 240V.}

May 18, 2008. 11:26 AMalexhalford says:

Sorry I explained it poorly, I meant that this circuit would be powered by a 9v DC supply, and the output would go to a mosfet, which would be in the AC wire. This circuit would only provide the pulses to turn the mosfet on and off, only the mosfet would experience AC, the rest of the circuit would not. Like this (You'll forgive me I hope, the crudely drawn diagram):

142

May 18, 2008. 11:42 AM

Kiteman (author) says:

I think you're best off asking somebody like Goodhart (or LasVegas if he's around).

May 18, 2008. 12:02 PMalexhalford says:

Ok, thanks anyway.

May 18, 2008. 2:21 AMalexhalford says:

Ok thanks, do you think a vacuum cleaner motor would do the job?

May 18, 2008. 10:24 AMsolo.card says:

I'd have liked it if you used clear eppendorfs, some of 'em were a bit tricky to see through. I was surprised by the strawberry jam. I think you should definitely blast that one for a little longer. So through looking at your past instructables of yours, I have come to the conclusion that you are either a science teacher, or evil genius. I hope both.

May 18, 2008. 6:08 AM

bosherston says:

Oh, I vaguely remember an O level physics lesson whereby a piece of cork and a paperclip were centrifuged - the cork sank and the paperclip rose? I don't remember the science behind it tho. Can you help Kiteman? Cheers.