Science Demonstrations

I performed various physics, chemistry and biology demonstrations in different classes.

The list of the demonstrations is as follows:-

1. Smoke Waterfall experiment
2. Row changing direction
3. Balloon pop experiment
4. Dancing beans experiment

SMOKE WATERFALL EXPERIMENT

I had performed this demonstration in class VIth B.

Materials required:- Medical tape, fork, conical flask, lighter

Procedure:- 

1. Take a medical tape and roll it up.
2. Place this roller inside a fork.
3. Then place this on the top of the conical flask.
4.  Lit the roller on top.

Observation:- The smoke from the paper tape tube falls instead of rise.

Explanation:- When paper tape burns, all the hot smoke molecules are being trapped into the paper tape tube which prevents them from rising. The trapped smoke molecules are given time to cool off and which releases the energy that allowed them to be lighter than air. Then the cooler smoke molecules fall instead of rise and escape out of the paper tape tube and creates the smoke waterfall effect.

ROW CHANGING DIRECTION

I had conducted this demonstration in class VIth B.

Materials required:- 100ml beaker, water, arrow drawn on one paper

Procedure:- 

1. Fill the 3/4th of beaker with water.
2. Place the paper behind the beaker.

Observation:- The arrow which is drawn on paper facing left, will look as if it is facing right when seen through the beaker.

Explanation:- This is due to the phenomena of refraction. Refraction is the bending of light. Whenever light passes from one medium to another, it refracts. The water, here, acts as a magnifying glass, which bends the light towards the center. The light comes together at the focal point and beyond the focal point, the image looks reversed because the light that was on the right is now on the left, and vice versa. 

BALLOON POP EXPERIMENT

I had performed this demonstration in Class VIIth C.

Material required:- Balloons, orange peel.

Procedure:- 

1. Blow one balloon
2. Peel off the orange
3. Take one peel of orange close to the blown balloon and squeeze it.

Observation:- The balloon pops immediately.

Explanation:- The juice from an orange peel causes a balloon to pop. A compound present in orange peel called limonene is a hydrocarbon and hydrocarbons are non-polar. Like limonene, rubber is a hydrocarbon, so its non-polar as well. Therefore, when the limonene oil contacts the surface of the balloon, some of the rubber balloon dissolves in the limonene. This weakens the balloon, causing it to pop.

DANCING BEANS EXPERIMENT

I had performed this demonstration in Class VIth A.

Materials required:- beans, Soda bottle, 100ml beaker

Procedure:-

1. Fill 3/4th of beaker with soda.
2. Put few beans into that beaker.

Observation:- Initially, beans sank to the bottom of the beaker but soon after that they starts dancing.

Explanation:- Carbonated beverages are filled with a dissolved gas called Carbon-dioxide which creates bubbles. These bubbles accumulate on the beans until the combined density of the beans and gas is less than the density of the soda. This makes the beans float to the surface as any object does when it is less dense than the liquid it has been submerged in. However, when the beans reach the surface, the bubbles pop. Once a bean is no longer covered in gas bubbles, it is more dense than the soda and it sinks back down to the bottom.

Once at the bottom, the bean accumulates gas bubbles again until it rises to the surface once more.