Explained: Beaker Ball Balance Problem

Summary

In this intriguing experiment, the narrator explores the principles of buoyancy and weight distribution using two balls in water-filled beakers. The heavier ball, when hung, causes the balance to tip due to the buoyant force it displaces, which is equal to the weight of the water it displaces according to Archimedes' Principle. The ping pong ball, however, experiences a counteracting force, resulting in minimal increase in the beaker's weight. An additional experiment is proposed, where a free ping pong ball is submerged, prompting viewers to predict the balance's behavior and engage in a discussion on the principles at play.

Takeaways

• 🔍 The balance experiment involves releasing a balance and observing its behavior.
• 🏋️‍♂️ The balance tips towards the right due to the heavier ball hanging on the right side.
• 💧 Both balls displace the same amount of water, which is a key factor in the experiment.
• 🔄 Archimedes Principle is invoked to explain the buoyant force acting on the balls.
• 🌐 Newton’s Third Law is used to describe the equal and opposite forces on the water in both beakers.
• 📚 The beaker with the hanging ball gets heavier due to the buoyant force supporting part of its weight.
• 🏓 For the ping pong ball, the downward force on the water is mostly counteracted by the tension in the string.
• 📉 The weight of the beaker with the ping pong ball only increases by the weight of the ball itself, not the displaced water.
• 🔄 The beaker with the hanging ball ends up being heavier due to the increased weight from the displaced water.
• 🧪 An additional experiment is proposed involving a free ping pong ball submerged just under the water surface.
• ❓ The audience is asked to predict whether the balance would tilt towards the hanging ball, the submerged ping pong ball, or remain balanced.

Q & A

What is the main event described in the script?

The main event is the demonstration of a balance experiment where two balls, one heavier and one lighter (ping pong ball), are placed in water-filled beakers to observe the effect on the balance due to buoyant forces.

What is Archimedes Principle mentioned in the script?

Archimedes Principle states that the upward buoyant force exerted on a body immersed in a fluid is equal to the weight of the fluid that the body displaces.

Why does the balance tip towards the heavier ball?

The balance tips towards the heavier ball because the buoyant force acting on the heavier ball supports some of its weight, reducing the tension in the string and increasing the effective weight of the beaker it's in.

How does the buoyant force affect the weight of the beaker with the hanging ball?

The buoyant force on the hanging ball supports part of its weight, which is then transferred to the beaker, effectively increasing the beaker's weight by the weight of the water displaced by the ball.

What happens to the weight of the beaker with the ping pong ball?

The weight of the beaker with the ping pong ball only increases by the weight of the ball itself, as the buoyant force is almost entirely counteracted by the tension in the string.

What is Newton’s Third Law and how does it relate to the experiment?

Newton’s Third Law states that for every action, there is an equal and opposite reaction. In the experiment, the buoyant force exerted by the water on the balls is balanced by an equal and opposite force exerted by the balls on the water.

What is the proposed additional experiment involving the ping pong ball?

The additional experiment involves submerging a free ping pong ball just barely under the water's surface and observing the effect on the balance when allowed to rotate.

What are the three possible outcomes of the additional experiment with the submerged ping pong ball?

The three possible outcomes are: A) the balance tilts towards the hanging acrylic ball, B) the balance tilts towards the barely submerged ping pong ball, or C) the balance remains perfectly balanced.

Why does the script ask for predictions and explanations from the audience?

The script encourages audience participation and engagement by asking them to make predictions and provide explanations, which helps to stimulate discussion and enhance understanding of the principles involved.

What is the purpose of the balance experiment in the script?

The purpose of the balance experiment is to demonstrate and explain the principles of buoyancy and weight distribution, as well as to challenge the audience's understanding and predictions of the outcomes.

How does the tension in the string affect the weight of the beaker with the ping pong ball?

The tension in the string counteracts the downward force of the water displaced by the ping pong ball, resulting in the beaker's weight only increasing by the weight of the ping pong ball itself, not the displaced water.

Outlines

00:00

🔍 Explanation of Balance Experiment

The presenter discusses the outcome of a balance experiment involving two balls, one heavier and one lighter (a ping pong ball). They explain that both balls displace the same amount of water, experiencing equal upward buoyant forces. Due to Newton's Third Law, equal and opposite forces are exerted on the water in both beakers. However, the heavier ball causes its beaker to gain more weight as the buoyant force supports some of the ball's weight, unlike the ping pong ball where the tension in the string counteracts the downward force. This results in the heavier ball's beaker being heavier overall.

🧪 Proposal for a New Experiment

The presenter proposes a new experiment: submerging a free ping pong ball just below the water surface with a finger. They prompt viewers to predict the outcome when the scale is allowed to rotate, offering three options: A) tilting towards the hanging acrylic ball, B) tilting towards the barely submerged ping pong ball, or C) remaining perfectly balanced. Viewers are encouraged to leave their predictions and explanations in the comments for a follow-up discussion.

Keywords

💡Prediction

In the context of the video, a prediction refers to a forecast or expectation about what will happen in the experiment. The speaker asks the audience to predict the outcome of the balance experiment involving the release of a balance and the behavior of the balls. This is a key element as it engages the audience in the scientific process and encourages them to think critically about the principles at play.

💡Balance

The balance in the video is a tool used to demonstrate the effects of buoyant forces and weight distribution. It tips towards the heavier side, illustrating the principles of physics involved. The balance is central to the experiment, as it visually shows the results of the forces acting on the balls and the water.

💡Buoyant Force

Buoyant force is the upward force exerted by a fluid that opposes the weight of an object immersed in it. In the video, the balls displace water, creating a buoyant force equal to the weight of the water displaced. This is a crucial concept as it explains why the balance tips towards the heavier ball.

💡Archimedes Principle

Archimedes Principle states that the upward buoyant force exerted on a body immersed in a fluid is equal to the weight of the fluid displaced by the body. The video uses this principle to explain why both balls experience the same buoyant force, despite their different weights.

💡Newton’s Third Law

Newton’s Third Law, also known as the action-reaction law, states that for every action, there is an equal and opposite reaction. In the video, this law is used to explain the forces acting on the water in the beakers, which are equal and opposite to the buoyant forces on the balls.

💡Tension

Tension in the video refers to the force exerted by the string supporting the hanging ball. It is used to illustrate how the weight supported by the string changes when the buoyant force acts on the ball, affecting the total weight of the beaker.

💡Weight

Weight in the video is the force exerted by gravity on an object. The weight of the beakers changes as a result of the buoyant force acting on the balls and the tension in the strings. The weight of the beaker with the hanging ball increases more than that of the beaker with the ping pong ball, leading to the balance tipping.

💡Ping Pong Ball

The ping pong ball is one of the objects used in the experiment. Its interaction with the water and the string demonstrates how the buoyant force and tension affect the weight of the beaker it is in. The video contrasts the behavior of the ping pong ball with that of the heavier ball.

💡Acrylic Ball

The acrylic ball is the heavier ball used in the experiment. Its behavior when submerged in water and hung from the balance helps to illustrate the principles of buoyancy and weight distribution. The video uses the acrylic ball to show the expected outcome when a heavier object is involved.

💡Experiment

The experiment in the video is designed to test and demonstrate the principles of buoyancy and weight distribution. It involves submerging balls in water and observing the effects on a balance scale. The experiment is the core of the video, driving the narrative and the scientific discussion.

💡Submerged

Submerged in the video refers to the state of being completely under water. The speaker proposes an additional experiment where a ping pong ball is submerged just under the water surface, without being tethered to the beaker. This scenario is used to further explore the effects of buoyancy on the balance.

Highlights

Prediction setup: Releasing balance with two balls, a heavier hanging ball, and a lighter ping pong ball.

Observation: The balance tips towards the right, towards the heavier hanging ball.

Explanation: Both balls displace the same amount of water, experiencing the same upward buoyant force.

Archimedes' Principle: Upward buoyant force is equal to the weight of the water displaced.

Newton’s Third Law: Equal and opposite forces down on the water in both beakers.

Expectation: Both beakers should get heavier by the same amount due to the buoyant force.

Hanging ball effect: The beaker with the hanging ball gets heavier because the buoyant force supports some of the ball's weight.

Tension reduction: The tension in the string of the hanging ball is reduced, increasing the beaker's weight.

Ping pong ball effect: The downward force on the water is counteracted by the upward force of the string's tension.

Weight change: The beaker with the ping pong ball only increases in weight by the ball's weight itself.

Comparison: The beaker with the hanging ball becomes heavier than the one with the ping pong ball.

Additional experiment: Submerging a free ping pong ball just under the water surface with a finger.

Prediction options: Tilting down towards the hanging ball, towards the ping pong ball, or remaining balanced.

Call to action: Viewers are asked to make predictions and explain their reasoning in the comments.

Future update: Results and explanations will be shared in the next update.

Transcripts

You have made your prediction and now it is time to see what happens when I release the

balance.

Ready?

In three, two, one.

The balance tips towards the right, towards the hanging, heavier ball.

But why does this happen?

Well, the best way I can think of to explain this is that both balls displace the same

amount of water.

So they both experience the same upward buoyant force which is equal to the weight of the

water they displace.

That is just Archimedes Principle.

But by Newton’s Third Law, that means there must be equal and opposite forces down on

the water in both beakers.

So you would think that both beakers would get heavier by this same amount.

Now for the hanging ball the beaker does get heavier by this amount, because the buoyant

force is now supporting some of the weight that used to be supported by this tension

in the string.

But it is now reduced and so beaker actually has more weight.

But for the ping pong ball, the downward force on the water is almost entirely counteracted

by the upward force of the tension in that string on the bottom of the beaker.

And, therefore, the weight of this beaker only increases by the weight of the ping pong

ball itself, whereas for the hanging ball the weight increases by the weight of water

it displaces.

So obviously this beaker is going to end up being heavier.

Now I want to propose an additional experiment.

What if instead of tethering the ping pong ball to the base of this beaker, I just got

a free ping pong ball and submerged it with my finger, just barely under the surface of

the water?

In that case, what do you think would happen when the scale was allowed to rotate?

Would it tilt down A) towards the hanging acrylic ball or B)

down towards the ping pong ball, which is now just barely submerged under the water

or C) would the balance remain perfectly balanced?So I want you to make your selection, make your

prediction by leaving a comment starting with either A, B or C and then giving me your explanation.

And I will tally up the votes and let you know the answer next time.