Static electricity is like a teeter-totter. What happens if a teeter-totter is balanced? Correct! It does not move. What about when its not balanced? Yes, it will now begin to move. Charges move when they are not balanced. Charges can build up by friction. Maybe you rub your feet on a wool mat or carpet. Rubber soled shoes readily gain charges. The wool carpet easily gives up charges. The two items become unbalanced. One item has a positive charge. The other has a negative charge. The difference in charge is called static electricity. Just like the teeter-totter, something is going to move. Positive charges build up on the mat. Negative charges build up on you.

Question: "How are electrical charges similar to a teeter-totter?"

Response: "Charges move when they are not balanced, just like a teeter-totter moves when it is not balanced"

A: yes

The Glory of Melaka: In the early days, if you were not a pirate or a mosquito, Melaka was not much of a place to live. The land was infertile, just a swampy plain, the river small and sluggish. But it had a sheltered harbor, protected from the monsoons by neighboring Sumatra. Later, the strategic location and deep-water channel close to the coast brought in the bigger vessels of the trade-wind traffic crossing the Indian Ocean. The first to realize the larger commercial potential, as so often throughout the country's subsequent history, were the Chinese. In 1409, under a new directive from Emperor Chu Ti to pursue trade in the South Seas and the Indian Ocean, a Chinese fleet of 50 ships headed by Admiral Cheng Ho called in at Melaka. They made Parameswara an offer he could not refuse: port facilities and an annual financial tribute in exchange for Chinese protection against the marauding Thais. In 1411, Parameswara took the money to Beijing himself, and the emperor gratefully made him a vassal king. Twenty years later, the Chinese withdrew again from the South Seas trade. The new ruler of Melaka, Sri Maharajah, switched his allegiance to the Muslim trading fraternity by marrying into the Muslim faith, wedding the daughter of a sultan in Sumatra. Islam won its place in Malaya not by conquestas had been the case in North Africa and Europebut by trade, dynastic alliances, and peaceful preaching. Bengali peddlers had already brought the faith to the east coast. In Melaka and throughout the peninsula, Islam thrived as a strong, male-dominated religion of individuality, offering dynamic leadership and preaching brotherhood and self-relianceall qualities ideally suited to the coastal trade. At the same time, Sufi mystics synthesized Islamic teaching with local Malay traditions of animistic magic and charisma, though Islam did not become the state religion until Muzaffar Shah became sultan of Melaka (14461459). But the key figure in the sultanate was Tun Perak, bendahara (prime minister) and military commander. He expanded Melaka's power along the west coast and down to Singapore and the neighboring Bintan islands. He also had orang laut pirates patrolling the seas to extort tribute from passing ships. After Ailied district chiefs had repelled assaults from Thai-controlled armies from Pahang, Tun Perak personally led a famous victory over a Thai fleet off Batu Pahat in 1456.

Question: "What advantage did Melaka's geography provide it?"

Response: "It had a sheltered harbor, protected from monsoons by neighboring Sumatra"

A: yes

Surely, you have noticed the tall poles along the roadside. Do you know what is on top of those poles? Thats right, wires that carry electric current. These wires carry electric current to your home. But what is electric current? Electric current is actually the flow of electrons. You may recall, an electron is the outer-most particle in an atom. They have a negative charge. Electricity is the continuous flow of these particles. Electrons are able to move through wires. Their speed can even be measured. The SI unit for electric current (or speed) is the ampere (A). Ampere is often shortened to amp. Electric current may flow in just one direction, or it may keep reversing direction. Direct current (DC) flows in only one direction. Direct current is what is used in devices like flashlights. Alternating current (AC) flows in two directions. This is the type of current that flows into your home through wires.

Question: "How many directions is the current flowing in that arrives through wires into our homes?"

Response: "Two"

A:
yes