Answer the questions:

1. What is Sir Isaac Newton famous for?

2. Where did he start his education?

3. How is his first famous work called?

4. What laws did he describe?

5. What are the three Newton’s Laws?

6. How was the gravity discovered?

7. What did Newton discover about sun’s gravity?

8. What role do distance and mass play in the force of gravity?

9. Who corrected many of the things that Newton did?

10. Where is Sir Isaac Newton buried?

3. Alessandro Volta

Volta was born in Como and educated in the public schools there. In 1775 he became professor of physics at the Royal School in Como; in the following year, he perfected the electrophorus, an instrument that produced charges of static electricity.

In 1776-77 he applied himself to chemistry, studying atmospheric electricity and devising experiments such as the ignition of gases by an electric spark in a closed vessel. In 1779 he became professor of physics at the University of Pavia, a chair he occupied for 25 years. By 1800 he had developed the so-called voltaic pile, a forerunner of the electric battery, which produced a steady stream of electricity.

In honour of his work in the field of electricity, Napoleon made him a count in 1810. A museum in Como, the Voltian Temple, has been erected in his honor and exhibits some of the original instruments he used to conduct experiments.

In 1775, Volta improved and popularized the electrophorus, a device that produces a static electric charge. His promotion of it was so extensive that he is often credited with its invention, although it had actually been invented in 1764 by Swedish professor Johan Carl Wilcke. In 1776-77 he studied the chemistry of gases, discovered methane, and devised experiments such as the ignition of gases by an electric spark in a closed vessel. Volta also studied what we now call capacitance, developing separate means to study both electrical potential V and charge Q, and discovering that for a given object they are proportional. This may be called Volta's Law of Capacitance, and likely for this work the unit of electrical potential has been named the volt. In 1779 he became professor of experimental physics at the University of Pavia, a chair he occupied for almost 40 years. In 1794, Volta married the daughter of Count Ludovico Peregrini, Teresa, with whom he raised three sons.

Around 1791 he began to study the "animal electricity" noted by Galvani when two different metals were connected in series with the frog's leg and to one another. He realized that the frog's leg served as both a conductor of electricity (we would now call it an electrolyte) and as a detector of electricity. He replaced the frog's leg by brine-soaked paper, and detected the flow of electricity by other means familiar to him from his previous studies of electricity. In this way he discovered the electrochemical series, and the law that the electromotive force (emf) of a galvanic cell, consisting of a pair of metal electrodes separated by electrolyte, is the difference of their two electrode potentials. That is, if the electrodes have emfs , then the net emf is . (Thus, two identical electrodes and a common electrolyte give zero net emf.) This may be called Volta's Law of the electrochemical series.

In 1800, as the result of a professional disagreement over the galvanic response advocated by Luigi Galvani, he invented the voltaic pile, an early electric battery, which produced a steady electric current. Volta had determined that the most effective pair of dissimilar metals to produce electricity was zinc and silver.

The battery made by Volta is credited as the first electrochemical cell. It consists of two electrodes: one made of zinc, the other of copper. The positively charged hydrogen bubbles start depositing around the copper and take away some of its electrons. This makes the zinc rod the negative electrode and the copper rod the positive electrode. The copper does not react, functioning as an electrode for the reaction.

However, this cell also has some disadvantages. It is unsafe to handle, as sulfuric acid, even if dilute, is dangerous. Also, the power of the cell diminishes over time because the hydrogen gas is not released, accumulating instead on the surface of the electrode and forming a barrier between the metal and the electrolyte solution. So it is not durable, and therefore, not a suitable choice.

In honour of his work in the field of electricity, Napoleon made him a count in 1810; in 1815 the Emperor of Austria named him a professor of philosophy at Padua.

He was a long-time correspondent of the Royal Society and received the Society's 1794 Copley Medal. He published his invention of the Voltaic pile battery in 1800 in the Philosophical Transactions of the Royal Society.

Volta is buried in the city of Como. At the Tempio Voltiano near Lake Como there is a museum devoted to explaining his work.

Answer the questions:

1. What is Alessandro Volta famous for?

2. What did he study in his works?

3. What was a forerunner of the electric battery developed by Volta?

4. What kind of device is an electrophorus?

5. What did he discover when studying the chemistry of gases?

6. How can you explain Volta’s Law of Capacitance?

7. How did he develop “animal electricity”?

8. What is the most effective pair of dissimilar metals to produce electricity?

9. How can you describe the battery made by Volta?

10. How was Volta awarded for his inventions?