Calculate strength of magnet

Magnets are everywhere. They can be permanent magnets or electromagnets. Magnets come in many shapes and sizes but they also come in different strengths.

It depends on what is meant by strength. Two common measures of a magnet’s strength are the strength of the magnetic field and pull force.

The magnetic field strength is expressed in Gauss or Tesla (1 Tesla = 10,000 Gauss). It depends on the size, shape, grade of the magnet and where the measurement is performed.

We will use a magnetometer sensor available in this smartphone to measure the strength of the magnetic field. Science Journal App is used to visualize data captured by the sensor.

As We move the bar magnet near the sensor, the strength of the magnetic field goes up. It comes back to original value as I move the bar magnet away. Same is true for other pole as well.

Electromagnet also behaves in a similar manner. We can see the proportional increase in strength with increase in current.

What if you don't have a magnetometer ? You can design your own scale with everyday things and compare the strength of the magnetic field quantitatively.

I will take this small steel ball and place it at a distance. I will slowly move the magnet towards the ball. The point at which ball is attracted towards the magnet is noted. We can note it down and compare the strength of all the magnets we have. Off-course this is our local scale.

Another way is to place a magnet in the bowl filled with balls and measure how many are attracted. By calculating the average, you can arrive at some number.

We can also compare strength based on the weight magnet can lift as well.

Let us attach this magnet to the wooden base here and calculate pull force. This nut with a container is stuck to the magnet. We will put balls in this container till it pulls the magnet down. This will be one measure of the strength of the magnet.

Same can be tried with a Neodymium magnet as well. It seems we need more force to pull the nut down. Let us tie this bottle and increase the force by adding water. It took 700 ml of water or approximately 7 Newtons.

You can try these variations to calculate the strength of the magnetic field.

Thank You.

[latabisht]

Sir, great video... Which magnetometer in the phone and app you are using in the early part of the video to measure the strength of magnetic field?

[juanmf]

Formula for number of balls or distance, to Gauss?

[alex-]

Does the neodymium magnet lose its properties?? if we melt it at high temperature

[javiermancheno]

Very creative Sir, kudos for you I larned a great deal, thanks for sharing your video !

[Ramius]

The magnet in the end may only hold slightly less than what the single one did I think. Only a guess. Magnets always were interesting to me.

[ManishaSharma-gcxt]

Thank you for this amazing video!
Can you please also tell that if the number of coins/balls/pins which get attached to the magnet are 10, then what will be the the magnet's strength in Tesla, will it be 10 Tesla or is there some formula to calculate the magnetic strength?

[moolsinghrathore]

सर, 1000 गॉस पॉवर का मैग्नेट कितना वजन उठता है।

[alanhurdle]

That is so cool the app, like this video thanks, I will use this information then by explaining forse and pull forse values conversation of strength creates metals to spin those bar or shaft are the energy ( eclectic power/mechanical power) magnetic electrical power generators good luck don't forget about I as broke as hell good luck

[harshgoel]

Sir
Is there a formula to calculate this for permanent magnets to determine shape, dimensions and grade depending on the application?

[devajchopda]

Sir,
I came across many equations that finds the strength of a magnet that forms a magnetic field when a wire carries electric current but is there any equation to calculate the strength of a permanent magnet (ferromagnets)?

[berkayakyel]

Sir
What is the size of Neodymium magnet which is used 700 ml of water ?