My TimelineBy Kip Cederstrom

1915 1929 1950 1963

I chose this because Alfred Wegener was the main person who knew about all this. He was also the only

one that actually had the guts to go up in front of everyone and tell them. If it weren’t for Alfred

Wegener, we might still be wondering about how the world works, or maybe not even know about plate

tectonics. Also, it’s pretty amazing that even so many years ago, they still were able to notice things like that and test them. Today, we could almost take a picture of the plates, but without Alfred Wegener,

we might not even think to look at them.

Alfred Wegener proposed a theory of Continental Drift.

I chose this because Harry Hess had very little technology back then. This was a huge breakthrough. With the technology we have today, we could

figure that out but he figures this out with none of what we have

today. Also, thermal convection is important. Without Harry

discovering this, we might still be wondering why heat rises.

Harry Hess’s theory that the

mantle goes under thermal

convection.

The nave used sonar to map the

ocean floor. Discovery of mid-

ocean ridges.

I chose this because I thought that this was important. The Navy would have the tools and money back then, more so than

some scientists. This is after Alfred’s theory, and technology has advanced, so

that’s where sonar comes in. Sonar is very cool. Today, we have sonar that can see hundreds of miles, and see way deeper

into the ocean, but in 1950, this is big. The Navy made a huge discovery.

Harry Hess was an important character in the 1900’s. This was his second breakthrough. I don’t know exactly where he got his ideas, but

they are true, and they seem impossible to figure out. Sea-floor

spreading is important because this could be partly why the continents

move. The magma pushes up and out, whilst moving the continents.

Harry Hess proposed the theory of sea-floor

spreading.