Lecture Notes on Earth's Internal Heat and Radioactive Decay

Flashcards reviewing key concepts from lecture notes on Earth's internal heat and radioactive decay.

What are the primary sources of heat within the Earth?

Residual heat from Earth's formation, friction from convection and plate movement, and radioactive decay.

How does radioactive decay contribute to Earth's internal heat?

Particles emitted during radioactive decay collide with other substances, generating thermal energy.

What is half-life?

The time it takes for 50% (half) of the atoms in a radioactive sample to decay.

What determines the rate of radioactive decay?

The percentage of nuclei that decay per given time period, known as half-life, which is constant for each radioactive isotope.

Explain why temperature increases with depth inside the Earth, despite the sun being the main energy source.

Radioactive decay within the Earth generates heat, causing the temperature to rise with increasing depth.

Describe the process of radioactive decay.

The process of a nucleus emitting charged particles and energy.

Why are larger atoms more likely to be radioactive?

Larger atoms contain more protons, increasing electromagnetic force, requiring extra neutrons to attempt to stabilize the nucleus; beyond atomic number 83, atoms are inherently unstable.

What happens during Alpha Decay?

The nucleus of a radioactive material emits a particle made up of 2 protons and 2 neutrons, decreasing the mass number by four.

What happens during Beta Decay?

The nucleus emits an electron (beta particle); a neutron breaks into a proton and an electron, resulting in the gain of a proton and the loss of a neutron.

What happens during Gamma Decay?

The nucleus rearranges itself into a lower energy pattern, emitting energy as gamma rays without emitting protons or neutrons.

What are the three different kinds of nuclear reactions?

Radioactive decay, fusion, and fission.

What is radioactivity?

The spontaneous changing of the nuclei of an atom from one element to another, releasing particles and energy.

What two forces are balanced in a stable atom?

Electromagnetic Force and Strong Nuclear Force.