ensic-balloons

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Loudspeaker Balloon

Steps to follow :

1- Inflate the balloon so that it is filled with air.

2. Hold the ball against your ear.

3. Lightly tap the other side of the balloon with your finger. Do you hear the sound well ? Can you feel the vibrations?

How it works :  When you puff into the balloon, you are pushing air molecules into the balloon. They are forced to settle in a small area and therefore are very close to each other. These circumstances allow air molecules to better transport sound waves. This is why you can hear the tapping so easily. It is as if you have built a loudspeaker.

Additional experiences: Add a mini marshmallow to the balloon. Does it muffle the sound? Does it sound the same?  If you have access to a helium tank, fill the balloon with that . Is helium a better conductor of sound than the air you pushed into the balloon?

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Want to see something fun? Click on the video! Here are some cool and fun science experiments you can do at home. 

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A balloon in the air!

In the movie Up by Pixar, a grandfather makes a flying house like a Hot Air balloon, thanks to a lot of balloons.

But how many balloons does he need?

How does a balloon fly?

When a system is immersed in a fluid, it undergoes the push of Archimedes.

  The system undergoes two forces: the weight and the push of Archimedes.

The total of external forces is the following :

However, in a balloon, the gas used is Helium.

Consequently, helium is lighter than air, so the balloon is carried up.

A standard volume of a balloon is about 2 litters. V=0,002 m3

F ext = 0,0205114 N

If we want to carry up an old grandfather, we need to compensate their weight:

Weight of a grandfather of 80 kg.

F grav = m×g = 784 N

 One balloon brings a force of 0,0205144 N to carry up the grandfather. Consequently, to carry up entirely the old man, we need more than 38 223 balloons! And to bring the man high in the air, maybe we need about 38 500 balloons.

 And for a house ? The weight of the carl’s house is estimated about 45 tonnes.

F grav = m×g = 441 000 N

One balloon brings a force of 0,0205144 N to carry up the house. Consequently, to carry up entirely the house, we need more than 21.5 million balloons! And to bring the man high in the air, maybe we need about 22 million balloons.

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Toothpaste for Elephants?

If you have been on social media lately, you might have seen videos of people combining chemicals together and colourful foams shooting up in the sky. It is called Elephant toothpaste.

What do you need?

Empty container

3%     hydrogen peroxide solution 

Packet     of active yeast

Liquid     dishwashing detergent

Warm     water

Food     colouring

Instruction

1.      Pour 1/2 cup hydrogen peroxide solution, 1/4 cup dishwashing soap, and a few drops of food colouring into the bottle. Swish the bottle around to mix the ingredients. Set the bottle in a sink or outdoors or some other place where you will not mind getting wet foam everywhere.

2.     In a separate container, mix a packet of active yeast with a little warm water. Give the yeast about five minutes to activate before proceeding to the next step.

3.     When you are ready to do the demo, pour the yeast mixture into the bottle. The reaction occurs immediately upon the addition of the yeast.

So how does it work.

Hydrogen peroxide (H2O2) is a reactive molecule that readily decomposes into water (H2O) and oxygen:

2H2O2 → 2H2O + O2(g)

In this demonstration, yeast catalyses the decomposition, so it proceeds much more rapidly than normal. The dishwashing detergent captures the oxygen that is released, making foam. Food colouring can colour the film of the bubbles, so you get coloured foam

In addition to being a nice example of a decomposition reaction and a catalysed reaction, the elephant toothpaste demo is exothermic, so heat is produced.

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Carnival Games! Is it a scam? How science can help you beat it?

Have you ever found yourselves spending tens and hundreds of dollars at the carnival? At those games that seems to be easy but is frustratingly impossible. Well, fret not, it is not entire your fault, you ‘renot lacking in ball tossing or balloon popping skills, those games are in fact rigged.

Why you ask? Well obviously, for profit. But guess what? Nothing science can help you fix. 

Each carnival game has its own ways of putting players at a disadvantage. For example, ball toss games, where light balls and bouncier balls are used. This decreases the players’ chance of landing on in. Any imperfections in the initial throw will cause the ball to bounce of and land elsewhere. Even on skill-based games, they are rigged. One of the most popular games is the basketball hoop game where the height and distance of the hoop is significantly more than of a three pointer.

Often, games like hit the bottles have bottom weighted bottles to make it nearly impossible to knock off. The key to this game is finding the right spot to hit the ball. Hitting the bottles on its neck wont to the trick, instead aim for the bottom. With enough kinetic energy, the entire bottle should just tumble down. But not too hard though, since people who throws the hardest are expected to lose in accuracy which as explain earlier is the key to winning this game.

Another popular carnival game is Toss the ball in the basket. The baskets are always positioned to be a bit slanted to increase the bounce effect of the ball, making the ball bounce off the basket at every throw. To properly land the ball in the basket, players need to hit the ball exactly on the rim of the basket to reduce enough kinetic energy to avoid the ball from bouncing out. This technique is found to be the most effective, but it is easier said and done, it must be thrown quite the distance.

So, the next time you’re at a carnival, give these tips and tricks a go and try to win a prize or two. Rigged or not, if we are having fun at it is not entire a loss. The bottom line is, understand a bit of science, can help you increase your chances in beating the game.

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Carnival Games! Is it a scam? How science can help you beat it?

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How to make your own Lava Lamp ?

For this beautiful experiment, you will need an empty glass, cold water, food coloring, cooking oil and salt.

Take the glass and fill it about three-quarters full with cold water. Stir in a few drops of food coloring. Can you guess what will happen when you add oil to water? Are they going to mix or separate? Which one will be at the top?

Add cooking oil until you have about a half inch of oil on water. Wait until the oil and water have separated into two layers before proceeding to the next step.

Sprinkle salt on top of oil. Keep adding salt to see what happens : Oil is lighter than water, so it floats. Salt is heavier than both oil and water, so it sinks. As the salt grains pass through the oil layer, it pick up drops of oil which temporarily clutch to the grains of salt and sink to the bottom of the glass. Then the oil drops free themselves from the salt grains and move upwards.