How well do you know your desserts?

Yummm... Isn't that mouth watering! Well, if you are thinking how the title could be a thought provoking question, you are on the right track. It isn't thought provoking at all. I didn't want to give away the essence of this post in the title itself. However, I assure you it has got to do something with a dessert.

Phew! This suspense building technique is not quite working out well for me. Let me do it the usual way. Today, In this post, you going to learn something new, and learn in it a fascinating kind of a way. It's something about desserts and a bullet !!! Yeah, that's right, I did say bullet. What could possibly connect a dessert and a bullet? Read on.

Let's perform (or rather watch) an interesting experiment. I'm going to place before you 4 kind of desserts : Whipped cream,  ice cream (vanilla flavour), chocolate sauce and english pudding. Each of these desserts are sandwiched between plastic sheets and are left on a table each. That is, imagine a box, plastic on front and back and wood on the sides, containing each of these desserts left on a table of its own. Now, we bring a shooter, a guy with a gun. We place a watermelon behind each one of these boxes  and ask the guy to shoot at the boxes one by one. How do you think each one of them would react to the gun shot? That is, can any of them stop the bullet and save the watermelon from blowing up gloriously? Take a moment to think and get ready with your answer and explanation and then watch this video from natgeo.

Amazing isn't it? I happened to accidentally come across this episode on the television, and the results left me wide eyed. Wow, a dessert that behaves bullet proof. How cool is that! I told this to my son (4 year old) and he asks me "Maa.. isn't that great. Now all that the soldiers have to do is to eat that english pudding before going to war. Nobody needs get hurt"!! I immediately hugged my cute little empathetic son and applauded him for his thinking.

However, imagine a bulletproof vest made from custard like fluid. How revolutionary would that be? ( This could be your debate topic with your kids today. The pros and cons of such a jacket )

Non newtonian fluid, did you guys know that there was something like that? Well, I didn't seem to remember that there was a category called newtonian fluid, leave alone the non-newtonian. So, we learn, non newtonian fluids are the ones that do not behave. So what is the expected behaviour of fluids or the newtonian fluids. Fluids include liquids and gasses. And what do both of them do normally? They flow. Now the resistance to flow is called viscosity. And what would the flow/viscosity depend on? Usually temperature. That is, if you freeze water (say), its flow reduces and it becomes a solid right?

Now imagine, you have a big tub of water and you hit it with a huge hammer in a sudden movement. Observe the water. It's still water. No big deal right? That's a normal liquid or a newtonian liquid. Now, Instead of water, we have a big tub of custard (say) and we hit it with a hammer. We see that when we hit it, it was like we hit a wall. Now we observe the custard. We dip our finger into it and see the custard dripping off our finger. So what just happened? It changed its behaviour with stress and got back to its original state when the stress was removed. Fascinating isn't it? That's exactly what happened to the custard during the gunshot. While hit with a bullet, the custard acted like a wall and protected the melon, however, the very next second, the custard oozed out of the hole the bullet had created on the plastic container. Did you notice that? That's the behaviour of a non newtonian fluid.

You know, what's more fascinating is that, this isn't all. There are types of non newtonian fluids. One kind behave like the pudding, that is, become solid or rigid when exposed to sudden stress. Type two, does just the opposite. Under stress, it becomes more liquidy. Now where have we seen that? Have you ever wondered why you had to shake the ketchup bottle with sudden jerks to get the ketchup 'flow' out of the bottle. Well, because, its another example of non newtonian fluid! Sudden stress, makes it flow-y. And a lot flowy at that. We almost always end up with excess ketchup on our plates. Isn't it? Have you ever wondered why??

Well, imagine the ketchup bottle was made of some metal and wasn't hollow. Had solid metal inside. Now try inverting it. Does the metal ooze out ? No. That's

metal's property, or rather property of a solid. It doesn't flow. On the other hand, fill the bottle with water. And invert it. What happens? All of it flows out. Thats liquid property. Mr/Ms ketchup has some soul searching to do and hasn't yet figured out if it wants to be a solid or a liquid. It doesn't behave. Apparently what happens is, when we hit the bottle hard, theketchup particles get squeezed and are able to move about freely. Once the effect of the pressure dies, they regain original shape and become non flowy again. Do watch the lovely TedEd video from this page.

The third type, continual stress makes this kinda liquid more flow-y or more liquid-y.. Can you think of examples of the same? Honey it is. Keep stirring honey and you will realise that after a while you find it easy to stir. Type 4 is the opposite of that. Keep stirring or keep applying some stress and this gets non flow-y. Example, whipped cream of course !

Exciting isn't it. Normal household items, that we see on an everyday basis at home, custard, honey, ketchup and whipped cream, all of them have been exhibiting different unruly behaviour and we didn't even notice and didn't think to ever question why ! Hmmm .. well there's the thought provoking question !

Some of you parents out there would've heard about this new fine motor aiding toy, the kinetic sand. Incase you haven't please watch this video. Kinetic sand is also a non newtonian fluid. Under pressure (when pressed into a mould), it behaves like a solid, however when you touch it slowly, it could flow like a fluid. It looks fun isn't it? Science is fun!

How about silly putty? Apparently, it was a very famous revolutionary toy for the kids in the 80's - 90's. For those of you who aren't familiar with it, please watch this youtube video ( for those hard pressed on time, watch the segment between 1:15 and  2:20 ). Again, the same thing. It shows non newtonian behaviour. When you stretch it slowly, it stretches like rubber, however, when you stretch it fast, it snaps. And it bounces like a ball! Cool isn't it?

How wonderful is science isn't it? The next time you try and squeeze ketchup out of the bottle, the next time you make custard at home, the next time you see a honey bottle, the next time you are whipping whipped cream at home, remember to tell your kids about non newtonian fluids, or at the least, help them understand that this liquid is misbehaving. Expand their horizon. Encourage them to ask thought provoking questions. The next time you chat with your friends over french fries and ketchup, ask them if they know why you have to hit the bottle to get the ketchup out.

Hey, I almost forgot Quicksand, the gooey otherwise innocent looking mud that is capable of swallowing you whole!! Elders might have told you, shouldn't struggle in a quicksand. Ever wondered why? Its a non newtonian fluid too. It behaves as a liquid under stress, and like a solid otherwise. So the more you struggle, the faster you drown! And did you know, the quicksand being denser than the human body, cannot drown you completely I read (As opposed to the many movies we've seen where the hero so sympathetically had lost his first love to the quicksand ) In order to escape the quicksand, we need to keep and stay calm, (to prevent further sinking) , take deep breaths (apparently to increase your buoyancy) , and slowly try to wiggle your legs towards the surface and monkey crawl on the quicksand to safety. So (God forbid) when in a quicksand, keep calm and remember me (I mean, this article) (Do read the many reference links below to get a good idea about quicksand)

So, science is fun (as seen in silly putty and kinetic sand), science is yummy (as seen is custards), science protects ( as with the promising future on liquid body armour and quicksand), science also lets you brag to your friends about how you know how to get out of a quicksand. Now, how cool is that! I love cool stuff. I love science. What about you?


References and links to some interesting videos you might want to see :
1. battling out of quicksand video 
2. https://www.sfsite.com/fsf/2012/pmpd1207.htm
3. http://sciencelearn.org.nz/Science-Stories/Strange-Liquids/Non-Newtonian-fluids
4. http://science.howstuffworks.com/environmental/earth/geology/quicksand2.htm
5. make your quick sand at home
6. http://www.damninteresting.com/the-physics-of-quicksand/
7. http://laughingsquid.com/an-explanation-why-ketchup-and-other-non-newtownian-fluids-are-so-hard-to-pour/

Disclaimer : This post and the linked videos are not meant as an advertisement to the products. Please don't consider this a recommendation. It was just to illustrate the concept of non newtonian fluids from the very objects/things/toys already available in the market.