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Radioactive Dating

Radioactive Dating

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Radioactive Dating

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  1. Radioactive Dating Hey, there! Can I get your number?

  2. Half-Life • Unstable atoms will break down to form other elements in a process called radioactive decay. • The rate at which an element decays is called its half-life • Half-life = the time it takes for half of the radioactive atoms to decay. • The half-life is used to determine the age of a rock or fossil. • Los átomos inestables se descomponen para formar otros elementos en un proceso llamado decaimiento radiactivo. • La velocidad a la que un elemento de desintegración se llama su vida media • La vida media = el tiempo que tarda la mitad de los átomos radiactivos a la caries. • La vida media se utiliza para determinar la edad de una roca o fósiles.

  3. Elements used in radioactive dating Carbon-14 Half-life = 5730 years Potassium-40 Half-life = 1.3 billion years Carbono-14 La vida media = 5730 años De potasio-40 La vida media = 1,3 mil millones años

  4. Sample problems How old is a fossil if its amount of carbon-14 is at 25%? ¿Qué edad es un fósil, si su cantidad de carbono-14 es del 25%? If we start at 100%, then 5,730 years need to go by to get down to 50% Another 5,730 years need to go by to get down to 25% (half of 50). Adding the two, we get, 11,460 years

  5. Sample problems How old is a fossil if there is only 6.25% of carbon-14 left? ¿Qué edad es un fósil, si sólo hay 6,25% de carbono-14 a la izquierda? 100  50 5730 years 50  25 5730 years 25  12.5 5730 years 12.5  6.25 5730 years 22920 years!

  6. Sample problems How old is a rock if its amount of potassium-40 is at 25%? ¿Qué edad es una roca, si su cantidad de potasio-40 es del 25%? 2.6 billion years old