Men, in contrast, are hypothesized to be most attracted to women in their reproductive prime, which tends to be when they are younger. Women’s preferences, on the other hand, hold relatively constant across their lives, not going more than a few years below their own age (extra-credit if you can identify the "cougar zone" in this figure), but women remain keen on men up to 10 years older than themselves. However, younger men (i.e., in their 20’s) tend to be married to someone of a similar age, but as they get older their wives get younger.
For example, by their 50’s the average male has a wife who is 10 years younger than him.
Time factors of millions and billions of years is difficult even for adults to comprehend.
However, "relative" dating or time can be an easy concept for students to learn.
Sequencing the rock layers will show students how paleontologists use fossils to give relative dates to rock strata.
Once students begin to grasp "relative" dating, they can extend their knowledge of geologic time by exploring radiometric dating and developing a timeline of Earth's history.
There is no independent natural clock against which those assumptions can be tested.
For example, the amount of cratering on the moon, based on currently observed cratering rates, would suggest that the moon is quite old.
Although age indicators are called ‘clocks’ they aren’t, because all ages result from calculations that necessarily involve making assumptions about the past.
Ages of millions of years are all calculated by assuming the rates of change of processes in the past were the same as we observe today—called the principle of uniformitarianism.
If the age calculated from such assumptions disagrees with what they think the age should be, they conclude that their assumptions did not apply in this case, and adjust them accordingly.
In this activity, students begin a sequencing activity with familiar items letters written on cards.
Once they are able to manipulate the cards into the correct sequence, they are asked to do a similar sequencing activity using fossil pictures printed on "rock layer" cards.