Detecting oncoming thunderstorms

Detecting oncoming thunderstorms

What are the components in this set up?

Open Ended

From previous slide, describe two ways lightning can form.

Franklin's bells in use

What are the components in this model?

Multiple Select

click on all the components that are part of this model.

• lightning rod

• franklin's bells

• electrical ground

• clouds

• trees

Open Ended

A metal lightning rod that extends above a house, as shown in Figures 2 and 3, will become electrically charged as a storm approaches. The negative charge of the cloud pushes negative charges already in the rod down to the connected bell (see Step 1 in Figure 4). Once the bell obtains enough negative charge, it attracts the neutral clapper. The negative charge is transferred from Bell 1 to the clapper. Once enough negative charge transfers to the clapper, the clapper is repelled from Bell 1, which pushes the clapper across to Bell 2. The negatively charged clapper touches the neutral Bell 2 and transfers its charge to Bell 2 through contact. Bell 2 is now negatively charged, but most of this charge escapes into the ground, leaving Bell 2 and the clapper neutral and ready to repeat the process. The clapper moves back and forth between the bells, ringing to warn of the coming storm.

Open Ended

Using the image or the previous slide-create a numbered step by step list of how the franklin bells work to prepare families for oncoming thunderstorms.

Franklin's Bells

• The device was originally created by the German scientist Andrew Gordon, but it was Benjamin Franklin who applied the principle to predicting thunderstorms. Therefore, the device is now called Franklin’s bells.

• Why must there be a different amount of charge on the two bells to make the clapper ring them?

think about how this model represents the Franklin's bells phenomenon in the house

• charged cloud

• Bells

• lightning rod

Fill in the Blank

The model in class represented the ______ _______ with the Van de Graaf generator. It represented the Bells using pop cans and finally, the lightning rod was the wire from the VDGG to the can.