Electroscope Lab

Before the Lab

What did the leaves look like? Hanging straight down.

What is making them stay in that position? Gravity

So….What did you observe?

What happened to the leaves when you touched the ball after being rubbed on the fabric?

They Spread apart

What happened to the rods when they were rubbed with the fabric?

They became either positively or negatively charged.

Observations….

Why did the leaves spread apart? Electrons were transferred off or on the rod.

What happened when you touched the ball of the electroscope?

The leaves returned to their natural position Electrons transferred to or from the rod to your

fingerto be neutral Neutral---equal electrons and protons Everything wants to be neutral

Observations cont…

Which piece of fabric added electrons to the rod?

Wool---which gave the white rod a negative charge

Which piece of fabric took electrons away from the rod?

Silk---which gave the clear rod a positive charge

Observations….

How do we know that one piece of fabric made the rod have a positive charge and the other have a negative charge?

Part D of the activity The leaves moved closer when the white rod

was close to the ball of the electroscope. Started to become Neutral If they were both negative/positive the leaves

would have gotten farther apart.

Conclusion

What is the name of this force that pushes the leaves apart by transfering electrons?

Electrostatic Force

What can we infer from this lab? Opposite charges attract Like charges repell The charge extends beyond the particle This is the 2nd strongest force in the atom

Elements Can’t be divided into any simpler

substances.

Atoms Smallest particle of an element that still

have all the properties of that element.

Subatomic Particles Proton—(+) charge, nucleus Neutron—(0) charge, nucleus Electron—(-) charge, electron cloud

Elements and Atoms

90 naturally occurring elements 20 synthetic elements

What is synthetic? Man made