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Pumas jump highest, brine freezes at -6° F, Dad and daughter raise tadpoles

 Q: What animal can jump the highest?

A high jumping puma [US Fish and Wildlife Service]

A: The puma wins the gold medal in the high jump. 15 feet (4.6 m)— 5 times its height. Pumas (aka mountain lions) have been known to drop to the ground from a height of 60 feet (18 m). The highest humans have jumped is 8 feet 5 inches (2.6 m).

However, it’s a different story relative to body size. The lowly flea wins hands down. Fleas jump 100 times their height. The elephant loses badly. It can’t jump — the only land mammal that can’t jump.

Q: Explain why salty water does not freeze even though the temperature falls below zero. —Tina, Sydney, New South Wales, Australia

Ice sheets form as crystals connect. [NOAA]

A: Salt crystals mess up the formation of ice crystals. Consequently, the water molecules must move much more slowly to form ice crystals. "Slower" motion means "colder." That’s why salt water doesn’t freeze unless the temperature falls considerably below the pure water freezing point (32° F, 0° C). How far below 32°? If the water contains as much salt as it can hold without salt coming out of solution (saturated), then the salt water won’t freeze until it cools to -6° F (-21° C).

We can think of the freezing process as a grabbing-hands dance. Pretend we’re water molecules. At first, we move fast (we’re liquid) so it’s hard to grab a hand. We slow (cool) and that makes it easier. We grab a hand (freeze). Some folks are aliens (salt crystals) and we don’t want to grab those hands. So we slow more and it’s easier to find the right hands.

As water cools, the molecules vibrate slower. Finally, the molecules are moving slowly enough that attractive forces between water molecules can stick molecules together. That’s called freezing. Then the molecules vibrate about a fixed position.

The 6-sided ice crystals build one on another to form sheets of ice. When salt (sodium chlorine) is mixed into the water, chlorine ions grab electrons from the hydrogen atoms in H2O. That interferes with ice-crystal building. It’s difficult, then, for the ice crystals to connect and so they must move slower to freeze.

Further Surfing:

USA Today, Weather basics: The three phases of water

University of Illinois, Champaign-Urbana: Melting and freezing

Pico Technology: freezing water and saltwater experiment

Q: I have a small aquarium full of little tadpoles (the American frog kind) and my first-grade daughter would very much like to see them grow into frogs. What can I do to keep them alive? Help a dad out, please. —Pastor Chuck, St Charles, Missouri

Tiny tadpoles are easy to raise [US Fish and Wildlife Service]

A: It’s not hard; here are five guidelines. Follow them and your little girl will soon see baby frogs hopping around.

Clean containers. Get something that is wide and short: large Styrofoam boxes or a small plastic "kiddies" pool, for example. "Wide and short" provides a large surface area compared to the volume of water. This ensures the tadpoles get enough oxygen. Avoid metal buckets because metal contaminates the water.

Put in a branch that the tadpoles can use to escape the container when they develop legs.

Clean water. Rainwater is best. If you live in the desert, use distilled or tap water. The tap water, however, has chemicals that kill tadpoles. So, let the tap water stand for a week to outgas the chemicals.

Half fill the containers with water. You need one quart (liter) of water for each tadpole.

Later on, clean the water by draining out half and refilling with clean water. You probably won’t have to do this often—whenever the water starts looking cloudy or like weak tea.

Good food. Give them lettuce or spinach—but not fresh or the water will go bad. Boil until soft. Freeze the leaves in an ice-cube tray. One cube feeds 10 or so tadpoles. Give them only enough that disappears in eight hours. Feed daily. Don’t use celery leaves.

Becoming frogs. The most important thing to do when a changeling emerges from the water is—remove it from the tadpole tank. If the baby frog falls back into the water, it can drown because it no longer has gills.

When you see a tadpole growing front legs, they are fast approaching frog-hood. Neat things happen:

Release the baby frogs where you found the tadpoles. You helped frog world by raising these in your home—a safe place. Many species worldwide are disappearing and we don’t know why.

Further Surfing:

Kay Heaton’s Organic gardening from down under: Caring for Tadpoles

Frog decline reversal project, inc: How to raise tadpoles

(Answered July 4, 2003)