simple science tricks

Simple Science Tricks – Clouds in a Bottle

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Clouds are beautiful! You look up to the sky and you see them in different shapes and sizes. What’s even more amazing is that they have different names for the different shapes; like Cirrus, Nimbostratus, and Cumulus. Though, the biggest question we had when we all saw those beautiful clouds (or sometimes sad clouds) is how are they made?

A cloud is a large collection of water droplets, very tiny ones, or ice crystals. Since the droplets are super small and tiny, they can float up in the air.

Actually, all air contains water to be practice. However, when we are near the ground level, or sea level, water is usually in the form of water vapor, which is invisible to us because of the distribution of water molecule in the space provided (imagine a pea in a football stadium and you are seeing the stadium from a helicopter).

When warm air rises, it expands and cools due to changes in the atmosphere itself. When the water vapor gets cold, the water molecules come together slightly closer and form tiny droplets; just like how we cuddle with someone when we get cold ourselves. This process is called condensation, when air molecules condense due to cold and slowly form into a liquid. When billions of these droplets come together, yet they are spaced not too far from each other, they become a visible cloud.

How does condensation work?

Condensation forms when water changes from a vapor (or gas) to a liquid. Consider the water molecules as people. For people to go around, hang out and meet with friends, they need energy. In the presence of heat, there is energy for things to happen (not extreme heat, of course).

People cannot stand extreme heat; otherwise, this place would have been packed!

So water molecules party it up and rock out everywhere in the air because of decent heat. However, as the water is cooled and there is less heat energy for the individual molecules and particles to move around, it then condenses. Just like cuddling. Therefore, condensation happens because of change in temperature.

How do clouds float?

Clouds are heavy. The water in a cloud can have a mass of several million tons. So, how do they float?

Cloud droplets are also about 1000 times heavier than evaporated (gas) water, so they are much heavier than air. However, they do not fall, but stay in the air, because there is warm air all round the heavier water droplets. You can imagine the warm air being bullies pushing the water to be together into a droplet.

When water changes from gas to droplets, this makes heat. Because the droplets are very small, they “stick” to the warm air. And thus, they float.

The Experiment

The Summary

Make some clouds in a bottle.

What you need:

  • Tea spoon
  • A 2-Liter bottle and a cap
  • Matches/Fire
  • Piece of Newspaper

Steps:

What’s going on?

As the video mentioned, the increase in pressure and decrease in pressure is increasing the temperature (remember how hot it is when using a bicycle pump?). This phenomena is better explained by this glorious formula, ideal Gas Law:

PV = nRT

No, we don't measure gas with those moles. Nor the moles on your body!

Where the volume (V) is constant because your gas is in the bottle of volume 2 liters, and there is a constant amount of gas (n) measured in moles, R is the ideal, or universal, gas constant, equal to the product of Boltzmann’s constant and Avogadro’s constant. And finally, T is temperature. As pressure changes often to higher pressure on average, it increases the change in temperature, leading to higher temperature (since the original temperature is constant).

Given the increase in temperature, change in pressure, and presence of water molecules in the bottle, clouds are formed satisfying the conditions and explanations mentioned above!

Simple Science Tricks – Tension Boat

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The Titanic can be considered a Tension Boat

The title may be misleading; one might think it is a very painful cruise ship vacation experience. However, today’s experiment will focus on surface tension of water and how we can use this property to propel objects on water. Surface tension can be seen everywhere in nature. Some examples include:

  • Water beads on waxy sufaces, like tree leafs or windows that are super clean. Water adheres weakly to wax and strongly to itself. Which leads to the phenomena of water drops coming together and forming a large drop on these surfaces
  • Separation of water and oil is caused by a tension in the surface between not-similar (or dissimilar) liquids. Normally, this is called Interface Physics, but its the same thing

A tension boat is basically a boat that utilizes the property of surface tension of water to propel itself in water. You might think that you can gain infinite propulsion force by placing ships in the ocean with enough material to harness this force and have green energy. But, it’s much more difficult than that, and I don’t think carrying gallons of soap and ocean water would work that easily.

What is Surface Tension

The straight up definition: The cohesive, or attractive, forces between liquid molecules causes surface tension.

Let’s consider the following image of a water molecule:

MEGA MASSIVE Water Molecule

As you can see, the water molecule consists of three atoms; two Hydrogen atoms (represented as white and positive) and an Oxygen atom (represented as red and negative). The “charges” you see on the molecules are due to the bonding between the Oxygen and Hydrogen atoms.

When Hydrogen gives away (shares out) their electron, it becomes positive (it hates being negative; imagine Hydrogen as someone high on life). On the other hand, Oxygen is like negative nancy or debbie downer, always negative and LOVES to get (or borrow) electrons.

Based on this property, it creates a “polar” molecule, which basically means that the molecule is like a magnet. A super super super super super super super super small magnet. And like any other magnets we nearly swallowed as a child in the world, they attract each other. Negatives attract the positives, and vice versa, and then you get like a chain of water molecules together. Therefore, in a glass of water, you have a party going on with the water molecules!

Water Molecules Partying to LMFAO!

As you can see in the party, the water molecules in the glass (or middle of the glass) are attracted from all sides and are influenced or “pushed” by other water molecules. However, for the water molecules on the surface, since they are not attracted from all sides (their top being open to air), they form a stronger attraction with their water molecule buddies around them. Because of this stronger attraction to the molecules to the sides of the water molecule, the surface of the water acts like an elastic surface!

And that, ladies and gentlemen, is how we have suface tension!

The Experiment

Summary

Make a small boat out of cardboard, place in water, add a drop of soap at the back-end of the boat, and watch that thing go!

What you need:

  • Water
  • Cardboard box
  • Soap or Detergent
  • Scissors
  • A clean kitchen sink, or round cake pan

Steps

  1. Cut the cardboard with scissors in one of the following shapes (You can make your own boat, just notice the back-end of the boat having an internal dent)
  2. Place the cardboard slowly on the surface of water (whether in the sink or round cake pan)
  3. Sing a Pirate Song!
  4. Add a drop or two of soap on the backend of the boat. Slightly dab the soap on the back
  5. See that bugger go!

What’s Going On?

So, you know about surface tension at this stage, and you noticed before you dabbed the boat with soap that the boat was still (unless your sink or whatever you used is so dirty and your boat went berserk, you dirty person you!).

The reason why the boat is still when placed in water is because the surface tension on the surface of water is acting on “all-directions” on the boat.

Let’s examine the property of soap. Soaps are compounds which are made by heating fats or oils, from animal or vegetable sources, with lye. A typical soap molecule has the formula:

CH3CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CO2-1 Na+1
Of course, unless you are an Organic Chemistry fan, you’ll be like “WOAH!” But to simplify all that stuff on top, we will make it look like this:

Looks like an electrocuted sperm...

Soap belongs to a class of chemicals known as surfactants, from surface active agents. As yours parents said, soap have some special properties which make them very useful for cleaning and forming bubbles and foam. In particular, the long hydrocarbon (All that C’s and H’s on top) ends of the molecules are very nonpolar and do not form bonds to water molecules. This end is hydrophobic (water fearing). On the other hand, the ends are very soluble in water and form rather strong bonds with the very polar water molecules. Those are hydrophilic (water lovin’).

When soap is placed at the end of the boat, the soap molecules order themselves in the position that will distort the surface tension of the water. The water molecules on the surface of the pool of water will lose their adhesiveness to each other because of the hydrophilic part of the soap. On the other end, water molecules are distancing themselves from the tail of the soap molecule. This can be shown in the following graph:

Soap molecules hatin' on water

Based on such interaction, aggregate effect of all forces will be “frontward” rather than “all-direction.” Such effect creates propulsion. Thus, you are capable of making the most awesome soap propelled speed boat!

Sources:

Bill Nye The Science Guy Being Epic!

Bill Nye The Science Guy and Surface Tension

Simple Science Tricks – Non-Newtonian Fluid

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What is a Non-Newtonian Fluid?

A non-Newtonian fluid is a fluid whose viscosity is variable based on applied stress, or force. Contrast with Newtonian fluids like water, whose behavior can be described exclusively by temperature and pressure (water at -32F/0C turned into ice, or water can be heated over it’s boiling point under high temperature), not the forces acting on it from second to second. Non-Newtonian fluids are fascinating substances that can be used to help us understand physics in more detail, in an exciting, hands-on way.

If you punch a bucket full of a shear thickening non-Newtonian fluid, the stress introduced by the incoming force causes the atoms in the fluid to rearrange such that it behaves like a solid. Your hand will not go through.

If you shove your hand into the fluid slowly, however, it will penetrate successfully. If you pull your hand out abruptly, it will again behave like a solid, and you can literally pull a bucket of the fluid out of its container in this way. You can try and walk on a non-Newtonian fluid if you stomp as best as you could on the surface.

A shear thinning non-Newtonian fluid behaves in the opposite way; where the application of force will make the solution act more as a liquid. In this type, the fluid becomes thinner, rather than thicker, when stress is applied. Also called pseudoplastic, examples of this type of non-Newtonian fluid include ketchup, toothpaste, and paint. The effect doesn’t usually last for long in either type, continuing only as long as the stress is applied. A good example is shaking the shaving cream can so the cream can be released from the can.

A practical application for shear thickening non-Newtonian fluids may be in body armor of the future. Since such fluids are usually flexible, they would allow soldiers to move freely when not under attack. But if confronted with a speeding bullet, they would quickly harder, performing like traditional armor. More research is necessary to see if non-Newtonian fluids are suitable for the military, but until then, it’s sure fun to play with.

The Experiment

Summary

Mix corn starch and water to create a non-Newtonian fluid. When left alone it will act like a liquid but when acted upon by a force it will react like a solid. If you hold it in your hand it will run through your fingers but if you punch the fluid it will harden

What you need:

  • Corn Starch (About as much water as you are using)
  • Water
  • Containers
  • Stirring rod (or anything to stir with)
  • Ice
  • Freezer
  • Microwave

Steps

Put water in a big bowl/container you adding corn starch until the water becomes extremely tough to stir. It has also been described as a syrupy texture, but you should be able to feel a difference. If you are not sure, you can test it by applying pressure with the poke of your finger or a spoon. You will feel and initial resistance by the fluid and then it will slowly release.

Experiment 1: Texture is Dependent on Ingredient

You will notice if you leave the fluid unattended for a spell, it will separate into two parts and solid will be on the bottom of the container. Simply mix it up once again to regain the non-Newtonian fluid texture.

As you poke and prod at the mixture, you can see and feel (if you use your hands) the mixture turning solid into liquid or vice versa. Get hands on! The texture is great to feel and will keep you occupied for hours on end!

After messing around for a bit, add more corn starch. This results in a more solidified liquid and you can better feel the reactions.

Experiment 2: Heat and non-Newtonian Fluid

The first additional experiment that was tested was by microwaving part of the fluid. I put it in the microwave for roughly 45 seconds on half power (5, in my case). This resulted in what looked like an egg-shaped object, with a yellow center and a white outer ring.

Experiment 3: Cold Temperature and non-Newtonian Fluid

In this experiment, I put a cup of the non-Newtonian fluid into a freezer to see the effects. After leaving it in there, it was examined later. It had some cool line patterns on the surface like it was exerting tension or something of the like.

Additional Random Experiments

Place the non-Newtonian fluid on a speaker that is protected by a layer of plastic. Play different sound frequencies and enjoy the patterns made by the fluid.

“After playing with my mixture a while, I started adding a lot more water then immediately microwaving it. Its almost like ballistics gel now.”

“blow bubles in it with a straw! they aren’t normal”

Credits and Sources

– WiseGeek – What is a Non-Newtonian Fluid?

– Instructables – How To Make Non-Newtonian Fluid Experiment