## Introduction: Ohm's Balloons

From switching a light bulb in our house On and Off to sending and receiving signals to the Mars rover, electrical circuits are ubiquitous in our day-to-day lives and Ohm's Law (V = IR) is as fundamentally important in electronics as Einstein's Relativity equation (E = mc²) is to physicists.

Ohm's law is the basis of all electrical systems. Electrical engineers use this equation to guide the design of electrical systems. Students need a strong foundation in Ohm's law while designing circuits on their own but it is observed that students often get confused between Voltage(V) and Ampere(I).

As a teacher, I have always been an advocate of Montessori education. I always try to include hands-on activities, role-plays, and games in my lesson plan to amplify the engagement, understanding, and learning of my students. So, here in my Instructables today, __I'm sharing an activity that my students love doing while understanding the difference between Volt and Amps__.

## Supplies

- 4 Large balloons
- Electric/Insulation Tape
- Scissors
- Screwdriver or any pointed object to poke a hole on balloons

## Step 1: Case I: High Voltage

__Procedure__:

- Take two balloons and fill them with water until it's about
**90 percent**full so that we have two balloons that are of the same size. - Tape the top portion of both the balloons leaving different-sized spaces(
**5 mm**and**10 mm**, respectively) in between. - Using a pointed object, poke a hole between the untaped square area.

__Observations__:

When we poke holes in the balloons we observe that:

- water starts flowing out of the balloons like a fountain.
- amount/volume of water coming out is different.
- water is coming out at the same rate/speed.

## Step 2: Case II: Low Voltage

__Procedure__:

- Take two balloons and fill them with water until it's about
**40 percent**full so that we have two balloons that are of the same size. - Now, tape the top part of the balloon leaving a small square space(hole) of about
**4-5mm**in the middle. - Similarly, tape the other balloon leaving a slightly bigger space(hole) of about
**10 mm**in the middle. - Using a pointed object, poke a hole between the untaped square area.

__Observations__:

When we poke holes in the balloons we observe:

- water starts flowing out of the balloons like a fountain.
- amount of water coming out is different.
- water is coming out at the same rate/speed.
- the height of the water fountain coming out of the balloon is higher in the balloon with a bigger hole as compared to the balloon with a smaller hole.

## Step 3: Understanding Observations

In this activity, we have assumed __the size of the balloons as the Voltage and the size of the holes as Ampere__.

In** Case I**, both balloons have around 9V, but one balloon has 10 A and the other has 5 A, ie the same amount of voltage but different amounts of current. Due to the bigger size of the balloons and hence higher pressure when we poke holes in the balloons it creates a lot of water outflow. We can see that water is actually coming out at the same rate/speed but the amount that is coming out is different.

Checking the result mathematically using Ohm's law:

Ohm's Law: V = IR or R = V/I

where V = Voltage, I = Current and R = Resistance (SI unit = Ohms)

**For balloon with larger hole:**

R = V/I

R = 9/10 = __0.9 Ohms__

**For balloon with smaller hole:**

R = V/I

R = 9/5 = __1.8 Ohms__

In **Case II**, with lower voltage or less water in the balloon, the pressure in the balloons is less, therefore water is not coming out that high or shooting up. Also, the water coming out from the balloon with a smaller hole is even less because Amp is different(less).

Checking the result mathematically using Ohm's law.

Ohm's Law: V = IR or R = V/I

where V = Voltage, I = Current and R = Resistance (SI unit = Ohms)

**For balloon with a larger hole:**

R = V/I

R = 2/10 = __0.2 Ohms__

** For balloon with smaller hole:**

R = V/I

R = 2/5 = __0.4 Ohms__

In both cases, we can clearly see the higher the value of R, lower the amount of water coming out of the balloon, ie R resists the flow of water from the balloon.

## Step 4: Result

According to Ohm's law, the current flowing in a circuit is directly proportional to the applied potential difference(V) and inversely proportional to the resistance(R) in the circuit.

In our activity, we observed that:

- the higher the voltage or water in the balloon, higher the pressure in the balloons.
- the amount of water coming out of the larger hole(higher Ampere) is more because it has less resistance as compared to the balloon with a smaller hole.

Therefore, the water flowing out of the balloons is directly proportional to the size of the balloons(V) and inversely proportional to the Resistance(R) generated because of the size of the balloon(V) and the size of the hole(A) in the balloons.

Runner Up in the

STEM Contest

## 12 Comments

4 months ago

Like the way you mix USCU with SI-system.

“5mm and 1 inch”

Reply 4 months ago

My bad. Thank you for point out. Corrected :-)

Reply 4 months ago

No problem. The USCU is riddled with units so you can toss in an extra unit without anyone noticing. :-)

4 months ago

Great visualization! If you use a small scale, you could make the weight of the water proportional to the voltage, explaining that the differential (since voltage is a differential) comes from the amount of water that is expanding the balloon and thus the balloon is trying to compress it back. The more water, the greater compression and the greater the differential.

4 months ago

I'm a middle-aged guy learning electronics and basic electricity for the first time, and this is the exact article I was wishing I could find this week. Very clear visualization, thank you.

Reply 4 months ago

Thank you InstructimusPrime :-)

4 months ago

I love it. Wish someone had explained it to me back in school like you did. It's always making a difference if you include hands-on activities in a learning process. Great Job, thank you.

Reply 4 months ago

Thank you for your appreciation sir :-)

4 months ago

This is a nice way to explain a difficult to understand concept. Great job!

Reply 4 months ago

Thank you :-)

5 months ago

What a great visualization :D

Reply 5 months ago

Thanks. My kids loves this activity(may because it includes balloons and water).