Have you ever looked closely at a globe? That continents look like a giant jig-saw puzzle. North America looks like it could fit next to Europe. The edge of South America matches Africa. Scientists noticed these same features. It caused them to start asking questions. They wanted to know if these continents were was connected? If so, how can something so large move so far? What could possibly have enough force to move such a giant slab of rock? Is there other evidence that can provide clues to the past positions of continents? How can answering these questions help us? A scientist named Alfred Wegener had these same questions. Wegener look at rocks on both sides of the Atlantic Ocean. He noticed they were the same type and age. He thought that the rocks must have formed side by side. He proposed that the rocks then drifted apart. One part went with North America. The other part stayed with Europe.

Question: "Wagner proposed that rocks drifted apart in which directions?"

Response: "Africa"
OPTIONS:
- no
- yes

A: no

Density is also an important physical property of matter. The concept of density combines what we know about an objects mass and volume. Density reflects how closely packed the particles of matter are. When particles are packed together more tightly, matter is more dense. Differences in density of matter explain many phenomena. It explains why helium balloons rise. It explains why currents such as the Gulf Stream flow through the oceans. It explains why some things float in or sink. You can see this in action by pouring vegetable oil into water. You can see a colorful demonstration in this video.

Question: "What does density tell?"

Response: "The distance between points"
OPTIONS:
- no
- yes

A: no

A handful of Bronze Age relics has fostered an assumption that prehistoric settlers inhabited Ibiza thousands of years ago. Greater evidence of such a people is found on Mallorca and Menorca than on Ibiza, but one of the Balearics' most important sites is actually on the island of Formentera, where the megalithic monument/tomb of Ca Na Costa has been dated to 2000 b.c. Ibiza's key location between Africa and ancient Iberia made it a convenient stopover for Mediterranean seafarers, such as the Phoenician traders, who called the island Ibosim. The Greeks dubbed it Ebysos, the Romans called it Ebusus, and the Moors, Yebisah. The Carthaginians: A detailed history of the island doesn't begin until it became a colony of Carthage in the 7th century b.c. . The Carthaginians originally came from the area comprising present-day Lebanon, and from their bases in North Africa and what's now Spain, they challenged the Roman Empire for domination of the Mediterranean region. Their interest in Ibiza lay partly in its vast salt flats, which to this day remain the source of a profitable industry. They capitalized on the natural resources by using the salt to cure fish, which they exported to their home country. The Carthaginians also carried out lead mining and continued to be of significance up until this century. It is believed that the lead pellets which were used by the Carthaginian general Hannibal were made on Ibiza. The Carthaginians also considered the island a holy place, and here in great splendour they buried thousands of their citizens in a huge necropolis on the Puig des Molins (Hill of the Windmills) below the Dalt Vila (Old Town) of Ibiza. Under the gnarled olive trees archaeologists have uncovered a treasure trove of statues, jewellery, pitchers, tools, and coins, which are now displayed in the town's two archaeological museums. The Romans never really infiltrated Ibiza, and even after the defeat of Hannibal in 202 b.c. during the Second Punic War their influence was restrained. Only with the fall of Carthage in 146 b.c. did they manage to make inroads, but, as local historians stress, Ibiza was neither conquered nor annexed by Rome, but confederated, retaining remarkable autonomy. For centuries to come the old Carthaginian traditions were allowed to continue on Ibiza alongside the new Roman way of life.

Question: "What did the Carthaginians want from Ibiza?"

Response: "Vast Salt Flats"
OPTIONS:
- no
- yes

A:
yes