Category: Learning Outdoors (Page 36 of 63)

Weekend Science Fun: Beach Science – Seawater

Is there a trip to the beach in your future this summer? Although trips to the beach are mostly pure fun, that doesn’t mean you can’t include a little science. Prepare for seashore science activities ahead of time and your children will have even more to discover when you get back home.

ocean

What do you usually see at the beach? Of course you’ll see sand, rocks and water. If you are lucky you may also spot some wildlife and algae. Over the next few weeks we are going to have a series of science discussions, experiments and activities on things you find at the seashore.

This week:  Seawater Science

It doesn’t take long at the beach to discover that seawater is salty. You can taste the spray on your lips. Ever wondered why seawater is salty or what is in it that makes it taste salty? There really is science in seawater.

1. Seawater pH

One easy experiment is to take along some pH paper and check how acid or basic seawater is. Compare it to other substances and to tap water.

Typically seawater is basic, that is higher than 7.0. Seawater pH is an important aspect of its chemistry because it impacts such processes as the laying down of calcium by corals.

2. Seawater salts

Gather:

  • Seawater
  • Plain water
  • 2 similar stainless steel or glass pans, or better yet, beakers
  • Heat source like a stove
  • Potholders

With the help of an adult, bring one cup of seawater in one pan and one cup of tap water in another pan to a boil. Turn down the heat and simmer until the water is almost dry. Watch carefully. Try not to let it boil completely dry because that will harm the metal of the pan. Remove from the heat and set in a warm place to finish evaporating away the water. What’s left?

Optional:  in a third pan place tap water and add a Tablespoon of salt. Boil as above. What happens when you evaporate the water in this case?

You should see a residue in the seawater pan. Pretend you are a chemist. How would you figure out what is in the residue?

One way is to do a flame test. When different chemicals are added to a flame, the resulting colors can give you information about what salts or elements are present. Here a trained chemistry teacher shows how this works.

Note: If you’d like to see how to do this, the book Fireworks by Vicki Cobb and Michael Gold (Photographer) has instructions for performing flame tests included as one of the activities. See Fireworks for the Fourth of July for a review.)

Using flame tests and other techniques, scientists have found over 70 elements in seawater.

How did those elements get into seawater? When I was young, I learned that the movement of freshwater over the earth’s crust picked up salts and carried them into the sea. Over time the salts built up because they are left behind when the water evaporates to move through the water cycle.

When I watched Going Deep on Scientific American Frontiers I found out that isn’t the only way salt gets in the ocean.

About thirty years ago, deep sea explorers found features known as hydrothermal vents along mid-ocean rifts. These are places on the ocean floor where seawater seeps into cracks in the crust. The water becomes extremely hot when it comes into contact with magma under the surface. It can’t boil, however, because of the extreme pressure at those depths. It dissolves some of the minerals from the crust and then flows back up into the ocean, carrying the dissolved minerals with it. Scientists have figured out that these vents are a significant source of the salts in the ocean.

A final process that provides salts to the oceans is the eruption of volcanoes under water. This is similar to the vents because the seawater is reacting with hot magma and lava, and dissolving some of the minerals in the liquid rocks.

Seawater is fascinating stuff and we still have a lot to learn about it.

Hope you have fun at the beach and watch out for those waves!

Resources:
(Affiliate links go to Amazon)

For the youngest set:

Hello Ocean by Pam Munoz Ryan and Mark Astrella (Illustrator)

For older kids:

The Magic School Bus on the Ocean Floor by Joanna Cole and Bruce Degen (Illustrator)

Blue Planet: Seas of Life DVD

Note: the linked page has some video clips.

For Adults:

A Scientist at the Seashore (Dover Science Books) by James S. Trefil

Edit: To check the rest of the posts on beach science, follow these links:

Sea Horses and Other Fish

Shore Birds

Tide Pool Invertebrates

Beach Science- Boats

Beach Science Algae

Beach Science-Sand

Bug of the Week: Long-horned Bees

Although the weather is uncomfortably hot for humans, things are still happening out in the garden here in Arizona.

sunflower

The sunflowers we planted for the Great Sunflower Project have started to flower.

The bees can hardly wait.

A few days ago these bees were sleeping on a nearby milkweed plant.

long-horned bee

long-horned bee

Long-horned bees (tribe Eucerini in the family Apidae) are named for the long antennae present on males. They have a habit of clustering in groups to sleep overnight on plants.

I’m not sure what species these particular bees are. There are over 30 genera in the tribe Eucerini, including Melissodes (the long-horned bees), Peponapis and Xenoglossa (squash bees), and Svastra (sunflower bees).

Hopefully we’ll be seeing bees on the sunflowers soon.

Summer Sounds 3: Frogs and Toads

In addition to the cicadas and tree crickets that we discussed previously, toads also sing at night in the desert.

Because it so dry for most of the year, desert toads stay dormant in underground chambers until the summer rains come. When the rains start, the toads emerge from the ground. They hop to nearby puddles, lay eggs, and attempt to complete their entire life cycle before the puddles dry out again. They don’t have long, often only about 7 days. The adults dig underground again and go dormant until the next rainy season.

We have several common species of frogs and toads, but one of the most amazing is the Couch’s spadefoot toad. Some people say they sound like sheep baaing.

Sheep baaing? Well, maybe.

Activities:

1. Get to know your local frogs and toads.

First of all, what is the difference between a frog and a toad?

As it turns out, the terms “frog” and “toad” are common names, they are not scientifically-based groups. According to frog taxonomists, all frogs and toads belong to a group called “frogs.” Although many people call the bumpy, dry land-dwelling creatures “toads” and the smooth-skinned, pond-dwelling creatures “frogs,” there are a number of species that are hard to place into one of those groups, such as the smooth-skinned spadefoot toads shown above. Check Frogs and Toads for more information.

To learn more about frogs, take a field trip to a pond or wetland.

Couch's Spadefoot Toad

Public domain photograph Gary M. Stolz, U.S. Fish and Wildlife Service, uploaded at Wikimedia.

 

Gather:

  • Boots
  • Pictures of frog and toad life stages
  • Identification guides if available
  • Camera and/or paper and pencil to record what you see

What you may see:

frog eggs

When I see frog eggs, I always think of punctuation. They start out a dark round periods, and then right before they hatch they turn into commas. Always leave eggs alone because handling them may damage their jelly coating.

tadpoles

tadpole

The larvae, commonly called tadpoles, are often easy to spot along the shore. Sometimes you may see a mix of different kinds. In this case the larger light-brown tadpoles are bullfrogs.

If you are very lucky, you may discover some of the tadpoles beginning to grow legs.

Ask everyone to be quiet and stand still in order to see adult frogs. Typically the adults swim away quickly when there are rapid movements nearby.

frog

Can you identify the adults? Are they common species?

Frog fact: Frogs regularly live 4-15 years, and sometimes much longer. Keep this in mind if you decide to raise one.

2. Frog Songs

Visit the same wetlands or pond at night to listen to frogs and toads singing. Ever hear the spring peepers? These tiny frogs can make a tremendous racket early in the spring.

If possible, make recordings of different types of frogs and toads singing. Or listen to recordings, such as at Sing to me baby! …Ribbit!

Try to mimic the calls yourself. Can you tell the different kinds apart? Before long you should be able to recognize different frogs based on their calls alone.

Older kids might want to try playing recordings of male frogs singing at ponds at night and see if they can attract female frogs.

Think of ways to design an experiment to find out if only the male frogs sing, or whether the females do too.

3. Eat or be eaten

While you are studying frogs and toads, try to figure out what they eat at each stage and what eats them.

The spadefood toads mentioned above eat insects that swarm at the same time the frogs are active. Both ants and termites tend to produce new queens and males in swarms when the summer monsoons start. At times the air will be filled with flying and mating insects. It is a great time for the toads to store up a lot of food to survive the rest of the year underground. Amazing!

Let us know what you find out.

For more information, try these resources:

Insect Lore Frog Life Cycle Stages

Nonfiction Books for Children:

Face to Face with Frogs (Face to Face with Animals)
by Mark Moffett

Mark Moffett is one of my favorite photographers. His work is often seen in National Geographic, which published this book.

From Tadpole to Frog (Let’s-Read-and-Find-Out Science 1)
by Wendy Pfeffer and illustrated by Holly Keller

Frogs by Gail Gibbons, a prolific and award-winning author

Frog (Watch Me Grow)
by DK Publishing

For the younger set.

Book for Adults:
Frog: A Photographic Portrait
by Thomas Marent and Tom Jackson

The Calls of Frogs and Toads
by Lang Elliott
Book and CD

Interested in learning more? See our growing list of children’s books about frogs and toads at Science Books for Kids.

Disclosure:
I am an affiliate for Amazon. If you click through the linked titles or ads and make a purchase, I will receive a small commission at no extra charge to you. Proceeds will be used to maintain this self-hosted blog.

« Older posts Newer posts »