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What does "softer" mantle mean?

In our science workbook it states, “Beneath the crust, Earth’s hot, softer mantle moves, too.”

Which got Clover and I thinking about what that actually means, a “softer” mantle? Like, are the rocks in it… squishy? We understand the concept as a system, how the crust moves over the mantle, but we find it difficult to imagine what the substance looks like, as if we could transport a cube of it to us to observe.

I turned to Earth's mantle - Wikipedia, and found:

It is predominantly solid but, on geologic time scales, it behaves as a viscous fluid, sometimes described as having the consistency of caramel.

Following the citations for that statement we get:

https://pds-ppi.igpp.ucla.edu/search/target/?t=Earth&m=NEAR

Earth is composed of four main layers, starting with an inner core at the planet’s center, enveloped by the outer core, mantle and crust. The inner core is a solid sphere made of iron and nickel metals about 759 miles (1,221 kilometers) in radius. There the temperature is as high as 9,800 degrees Fahrenheit (5,400 degrees Celsius). Surrounding the inner core is the outer core. This layer is about 1,400 miles (2,300 kilometers) thick, made of iron and nickel fluids. In between the outer core and crust is the mantle, the thickest layer. This hot, viscous mixture of molten rock is about 1,800 miles (2,900 kilometers) thick and has the consistency of caramel. The outermost layer, Earth’s crust, goes about 19 miles (30 kilometers) deep on average on land. At the bottom of the ocean, the crust is thinner and extends about 3 miles (5 kilometers) from the sea floor to the top of the mantle.

Earth is composed of four main layers, starting with an inner core at the planet’s center, enveloped by the outer core, mantle, and crust.

The inner core is a solid sphere made of iron and nickel metals about 759 miles (1,221 kilometers) in radius. There the temperature is as high as 9,800 degrees Fahrenheit (5,400 degrees Celsius). Surrounding the inner core is the outer core. This layer is about 1,400 miles (2,300 kilometers) thick, made of iron and nickel fluids.

In between the outer core and crust is the mantle, the thickest layer. This hot, viscous mixture of molten rock is about 1,800 miles (2,900 kilometers) thick and has the consistency of caramel. The outermost layer, Earth’s crust, goes about 19 miles (30 kilometers) deep on average on land. At the bottom of the ocean, the crust is thinner and extends about 3 miles (5 kilometers) from the seafloor to the top of the mantle.

So… caramel! Does that mean such as magma/lava? Does it glow orange, that being the reason it is colored that way in illustrations?