Uranium, named after the planet Uranus, has the second largest atomic mass among naturally occurring elements, only surpassed by plutonium. It is weakly radioactive and contributes significantly to the earth's internal heat. Despite its low concentration in soil, rocks, and water, uranium is more abundant than silver. Historically, uranium was used to color glass, and today it plays a crucial role in nuclear technology and military applications due to its high density. Uranium-238, its most common isotope, has a half-life of over 4 billion years, making it valuable for determining the earth's age.

What is the primary source of heat in the Earth's interior?

• Radioactive decay of uranium

• Solar radiation

• Volcanic activity

• Geothermal vents

Before its radioactivity was known, uranium was how many times more abundant than silver?

• 40 times

• 10 times

• 20 times

• 30 times

What was uranium historically used for in glassmaking?

• To increase glass transparency

• To give glass a yellow color

• To make glass more durable

• To make glass heat resistant

Which property of uranium makes it useful in military applications?

• Its radioactive nature

• Its high density

• Its abundance

• Its color

What is the half-life of uranium-238?

• 6 billion years

• 2 billion years

• 1 million years

• 4 billion years