Rub the yellow balloon on the sweater until you get all of the blue negative charges on the balloon. When you rub two things together and there is a transfer of negative charge, this charge distribution is called friction. Now, drag the balloon in between the wall and the sweater. Then release the balloon to see what happens. Explain what happened and why.
The scenario you're describing is an example of an electrostatic phenomenon. Here's a step-by-step explanation of what's happening:
1. **Rubbing the Yellow Balloon on the Sweater:**
When you rub the yellow balloon on the sweater, you're adding energy to the system through friction. This energy allows electrons (which carry a negative charge) to be transferred from the sweater to the balloon. The material of the sweater gives up electrons more readily than the balloon material. This is due to the triboelectric effect, where certain materials become electrically charged after they come into frictional contact with a different material.
2. **Electron Transfer - Negative Charges on the Balloon:**
As a result of the rubbing, the balloon becomes negatively charged because it has gained electrons from the sweater. These electrons repel each other and try to get as far away from each other as possible, spreading over the surface of the balloon.
3. **Dragging the Balloon between the Wall and the Sweater:**
When you move the negatively charged balloon near the wall, you don't have to actually touch the wall. The electrostatic charge on the balloon will begin to affect the charges in the wall.
4. **Release the Balloon:**
Upon releasing the balloon, you might notice it sticks to the wall. The reason for this is that the negatively charged balloon induces a redistribution of charges in the wall. The wall is generally neutral, but the electrons in the wall's atoms will repel away from the balloon's negative charge, causing the side of the wall's surface closest to the balloon to become positively charged. This happens due to the principle that opposite charges attract; the negative charge on the balloon is attracted to the positive charge on the wall's surface.
5. **Explanation of What Happened:**
The balloon sticks to the wall because of the attractive electrostatic force between the negatively charged balloon and the induced positive charge on the wall's surface. This force is strong enough to overcome the force of gravity pulling down on the balloon, at least temporarily.
This phenomenon will only last as long as the charge on the balloon remains. Over time, the electrons will slowly redistribute themselves (possibly by transferring to the wall or the air molecules, or by recombining with positive ions in the surroundings), and the balloon will eventually fall when there is no longer sufficient electrostatic force to keep it against the wall.