If you’ve ever looked closely at your own fingertips, you’ve probably noticed that the skin is grooved with very, very thin lines in a spirally pattern.  That’s your fingerprint, and it is your very own: every single person has his or her own special pattern. There are six basic styles of fingerprints, though: loop from right, loop from left, arch, whorl, double loop, and “eclectic,” which basically covers all the weird remaining ones that don’t have a name. These grooves in our fingers help us grip objects — but as a special bonus, fingerprints also leave tracks showing exactly whose fingers they are. You can use your fingerprints on scanners to get permission to open doors, but your fingerprints can also show that you were the thief who opened the cookie jar.  Just one more good reason to wash your hands.

Wee ones: There are 6 types of fingerprints, but half of those involve “loops.” How many loopy fingerprint types are there?

Little kids: If you have messy chocolate all over one hand, and you fully touch the table with that hand 3 times, how many total fingerprint marks do you leave on the table?  Bonus: If 2 friends each have both hands covered with chocolate and they each rest all 10 fingers on the table, now how many total fingerprints are there?

Big kids: One way to see your fingerprint is to press your finger on an ink pad, then on a fresh empty balloon, and then blow up the balloon to watch the design stretch out. If your fingerprint covers a space that gets 5 times as tall and 5 times as wide when you inflate the balloon, how many of your original fingerprint could fit in that new space?  Bonus: If that area now doubles in each direction, now how many times as big is it relative to your original fingerprint?

The sky’s the limit: Suppose your class at school has 12 boys and 12 girls, all with loop, arch or whorl fingerprints.  If half the boys and 2/3 of the girls have loopy fingerprints, and half the remaining kids have arch fingerprints but that includes 3 more boys than girls, how many girls have whorls?

Answers:
Wee ones: 3 loopy types.

Little kids: 15 fingerprints.  Bonus: 35 fingerprints, since the friends added 20.

Big kids: 25 fingerprints.  Bonus: 100 times as big.

The sky’s the limit: 6 boys and 8 girls have loops, leaving 6 boys and 4 girls with other types.  Half, or 5 in total, have arches, but if that includes 3 more boys than girls, then only 1 girl has arches (along with 4 boys). That leaves 3 girls with whorls.

It’s pretty exciting when a volcano explodes and shoots red-hot lava, which is melted rock. Well, nature does this with water, too. A geyser is a rare underground spring that sometimes bursts up through the ground.  One of the most famous geysers is Old Faithful in Yellowstone National Park.  It gets its name because it is very predictable: it erupts every 91 minutes, shooting hot water and steam up to 185 feet in the air for as long as 5 minutes at a time. In the old days, people tried to use Old Faithful to wash their clothes, but found that it was too powerful and the blasting water tore everything to shreds.  Because of changes in the earth, the length of each eruption and the amount of water that comes out have both changed, too. But Old Faithful still deserves its name, as it still shoots boiling water high into the air about every hour and a half – whether you’re waiting to do laundry or not.

Wee ones: If you can spray water out of your mouth for a whole minute straight, but Old Faithful can blast water for 5 minutes straight, how much longer than you can Old Faithful spray?

Little kids:  Is 185 feet about as tall as a person, a building, or a mountain?  Bonus: If the last eruption ended at 3:10 pm, at what time will you see the next one if it’s 91 minutes later? (Reminder: there are 60 minutes in an hour.)

Big kids: For a sense of how tall 185 feet is, you can compare it to other tall things, like a house. If each story adds 10 feet of height and so does the roof, about how many houses with 2 stories and a roof do you have to stack to match Old Faithful?  Bonus: You can also compare to an American football field, which is 120 yards long. About what fraction of a football field standing on end would the highest eruption match? (Reminder: a yard equals 3 feet.)

Answers:
Wee ones: 4 minutes longer.

Little kids: About as tall as a building with 18 floors.  Bonus: 4:41 pm.

Big kids: Each house is 30 feet tall, so you’d need about 6 houses, which stack to 180 feet.  Bonus: A football field is 360 feet high, so 185 feet is about half a football field.