Beach science

Beach science.

With Bonus information - For the extra curious scientist. 

1. Sand Exploration.

Materials (sand, black paper, magnifying glass or microscope, vinegar )

1. Sprinkle some sand on the black paper.  Try to spread it thin enough that you can see individual grains of sand.

2. Look at it through the magnifying glass.

3. Try it again with different types of sand.  Use dry sand from the top of the beach, wet sand from near the water, or even sand from your sandbox.  Notice the different shapes, sizes and colors of the sand.

4. Put a bit of vinegar on the sand and watch what happens.

What Should Happen

At first glance, sand may look like it is all one color.  When you start to look at individual grains of sand, you will see the many colors, shapes and sizes of the different grains.

If some of the sand grains give off tiny bubbles when you add the vinegar, that means they were once part of a living being.  They could be bits of coral, shells, or bone.

Still curious ? 

Why does the color of sand change beach to beach ?

Light colored sand - when rivers and streams transport quartz particles also maybe feldspar and other rock fragments. 

Where do we find this ?  Usually on Continental sand fed by rivers and streams.

White colored sand -  is made up less of quartz more of calcium carbonate, which comes from the shells and skeletons of reef-living marine organisms, including corals, mollusks and microorganisms called foraminifera. This colored sand forms when the reef breaks down, either by mechanical forces — such as waves and currents — or from bio-erosion caused by grazing fish, urchins and other marine life.  FUN FACT - Also poop specifically according to the National Ocean service from the poop of parrotfish. The fish bite and scrape algae off of rocks and dead corals with their parrot-like beaks, grind up the inedible calcium-carbonate reef material (made mostly of coral skeletons) in their guts, and then excrete it as sand. At the same time that it helps to maintain a diverse coral-reef ecosystem, parrotfish can produce hundreds of pounds of white sand each year!

Where do we find this ? On Tropical Islands such as Hawaii and the caribbean islands as Island coastlines  are less steam and river fed than on the continent.

Pink colored sand-   caused by eroded calcium carbonate; the sand gets its ruddy hue from the abundant red foraminifera, Homotrema rubrum formed by the perpetual decay of single celled shelled organisms.. 

Where to find this ?  Bermuda has a famous pink sand beach.

Black colored Sand -  is composed of black volcanic glass, eroded volcanic material such as lava, basalt rocks, and other dark-colored rocks and minerals, and is typically found on beaches near volcanic activity. 

Where to find this ? Black-sand beaches are common in Hawaii, the Canary Islands, and the Aleutians.

Green tinted Sand - again volcanoes are the source - sometimes, erosive forces separate the mineral olivine from other volcanic fragments, leading to green sand beaches

Where do we find this ? Hawaii's Papakōlea Beach.

To view some of these sands mentioned above go to Geology.com

Bonus Geography - look up the places mentioned on a world map.

2. Make your own tide pool

Learn all about how tides impact sea life by creating a coastal scene with shells and sea life figures or get creative and design a prehistoric tidal environment with dinosaurs! No matter what kind of seascape your little researcher constructs, the lessons remain the same. This experiment shows low tides, high tides and even the effects of waves.

Click HERE to view

Still curious ?

Let the National Ocean Service help you out. Or the Ocean Conservancy. 

3. Make your own saltwater v plain water test for buoyancy

 Key concepts Vocabulary

• Density - substance of a mass per unit volume

• Mass - a measure of the physical volume or bulk of a solid body

• Volume - the amount of space a substance or object occupies when contained in a container. The amount of mass per unit of volume is density.

• Concentration - the relative amount of substance per confined space. 

• Buoyancy - the ability that something has to float on a liquid or in air.

• Water - a chemical compound consisting of two hydrogen atoms and one oxygen atom. 

Introduction

Have you ever wondered why some objects float in water and others sink? It has to do with the density of the objects compared with the density of the water surrounding them. If an object is less dense than the water around it, it will float. Because salt water is denser than freshwater, some things float more easily in the ocean—or extremely salty bodies of the water, such as the Dead Sea. You can make your own dense water by adding salt to tap water. In fact, if you add enough salt, you can make the water so dense that an egg will actually float in it! Explore how this works in this science activity.

You will need

• One bowl

• Measuring cup

• 5 Plastic cups

• Water

• Salt 

• A bar of soap (or egg - room temperature for older children. Be sure to wash your hands after handling the egg)

• Paper and pen

What to do ?

1. Label cups 1-5

2. Pour ½ cup tap water into the cup labeled 1

3. Using the measuring cup mix 2 cups of  tap water with ¼  cup salt.

4. Stir well until dissolved 

5. Pour ½ cup from the measuring jar solution  into cup labeled 2

6. Add ½ cup more water and ¼ cup more salt to the water remaining in the measuring cup. Mix till dissolved.

7. Pour ½ cup from the measuring jar solution into the cup marked 3

8. Add ½ cup more water and ¼ cup more salt to the water remaining in the measuring cup stir until dissolved.

9.   Pour ½ cup from the measuring jar solution into cup marked 4.

10. Add ½ cup more water and ¼ cup more salt to the water remaining in the measuring cup. Mix till dissolved.

11. Pour ½ cup from the measuring jar solution into the cup marked 5 

12. Make a guess (Hypothesis) as to what will happen ?

13.  Try to float the soap/egg in each cup and record what happens.

14. What happened ? Why ?

Still curious ? 

• Why is the sea salty? 

Salt in the sea, or ocean salinity, is mainly caused by rain washing mineral ions from the land into water. The rain that falls from the sky is not just pure water – it actually contains small amounts of chemicals called carbon dioxide and sulphur dioxide (acids) , which are absorbed by the water while it is still in the air. This means that rain is actually very slightly acidic (but not enough to do you any harm). When the rain falls on the ground, this weak acid can dissolve small amounts of mineral salts from the rocks, including sodium and chloride, (this is called weathering) these salts then enter the water. Sodium chloride is the main salt in seawater, and the same one you might have on your table at home. The rain water flows off the land and into the rivers and streams that lead all the way to the sea – carrying the dissolved salts along with it.

Some salts can also enter the seas from hot vents on the deep ocean floor and from volcanoes on the land and in the sea. Some salts (particularly chloride) are also moved around as part of the water cycle – these are known as “cyclic salts” and originally came from volcanoes

•  Why is the sea salty and rivers not?

In fact, rivers are only carrying very low levels of salts. The salts in the seas have built up over billions of years, and seawater contains about 300 times more dissolved salts than average river water. To put it another way, every one litre of seawater has 35 grams of salts dissolved in it, while a litre of freshwater would only have 0.5 grams. That’s why we say that seawater has a much higher concentration of salt – or “salinity” – than the freshwater flowing through rivers and streams.

Rain replenishes freshwater in rivers and streams, so they don't taste salty. However, the water in the ocean collects all of the salt and minerals from all of the rivers that flow into it so it collects salt.

5. Make your own quicksand.

You will need:

• 1 cup of maize cornflour

• Half a cup of water

• A large plastic container

• A spoon

 Instructions:

1. This one is simple, just mix the cornflour and water thoroughly in the container to make your own instant quick sand.

2. When showing other people how it works, stir slowly and drip the quick sand to show it is a liquid.

3. Stirring it quickly will make it hard and allow you to punch or poke it quickly (this works better if you do it fast rather than hard).

4. Remember that quick sand is messy, try to play with it outside and don’t forget to stir just before you use it.

5. Always stir instant quicksand just before you use it!

Still curious ? 

What is Quicksand ?

Quicksand is a mixture of sand and water, or sand and air, that looks solid, but becomes unstable when disturbed by any additional stress. In normal sand, grains are packed tightly together to form a rigid mass, with about 25 to 30 percent of the space (voids) between the grains filled with air or water. Because many sand grains are elongated rather than spherical, loose packing of the grains can produce sand in which voids make up 30 to 70 percent of the mass. This arrangement is similar to a house of cards in that the space between the cards is significantly greater than the space occupied by the cards. The sand collapses, or becomes 'quick,' when additional force from loading, vibration or the upward migration of water overcomes the friction holding the grains together.

Most quicksand occurs in settings where there are natural springs, either at the base of alluvial fans (cone-shaped bodies of sand and gravel formed by rivers flowing from mountains), along riverbanks or on beaches at low tide. In such cases, the loose packing is maintained by the upward movement of water. Quicksand does occur in deserts, but only very rarely: where loosely packed sands occur, such as on the down-wind sides of dunes, the amount of sinking is limited to a few centimeters, because once the air in the voids is expelled the grains are too densely packed to allow further compaction.

6. Use science to build the best sandcastle.

Tips to success:

Equipment:

You don’t need any fancy equipment to make a fancy sandcastle. Everything you need can likely be found in your kitchen, garage or local hardware store.

• A long-handled, lightweight shovel: a long-handled shovel with a small scoop. 

• A bucket or two

• Plastic molds: Use plastic food containers to make towers and building blocks. 

• Carving tools Look in your kitchen for smoothing and shaping tools: for basic shaping, plastic knives, paint scrapers and trowels. A pastry knife or small spatula work well for detail work. Plastic spoons to carve out windows.

• Finishing tools: A soft-bristled paintbrush is handy for smoothing surfaces. A paper straw works well for blowing loose sand out of detailed carving.

• Be creative cookie cutters, ice cream scoops even muffin pans can upgrade your castle to the next level.

Technique and tips:

Notice what happens if the sand is too wet. Explore different ratios of water and sand.

• Fill your building bucket with sand: Did you find the right ratio of water and sand? Try filling your bucket about 90% full with sand and the rest with water. How is that ?

• Mix up your sand: Pour water into the building bucket where you put your sand – and fill it right up to the top. Then reach in with your hands and really mix and mix and mix to get all the sand particles in the entire bucket all coated with water. (Fun fact: this is what cement mixers do!)

• Compact wet sand:  Packing sand strengthens and tightens the little water bridges that hold the grains together. Tap the sides of your bucket with your fists or your feet until the sand on top looks compact and almost dry. Then carefully lift off your bucket a gently shake of the bucket will ease the sides

• Carve, build, decorate: Use your finishing tools – and your imagination! – to create the sandcastle structure of your dreams.

• Don’t forget to dig the moat and decorate with shells, stones and driftwood.

Still curious ? 

The science behind sandcastle building has to do with the interaction between water and sand, and with a special force called “surface tension.” (Yes, pull that word out to impress your children.) In case you need a refresher from your high school physics class, surface tension is the force that causes water molecules to be attracted to one another. Think about what happens when you fill a glass of water to the VERY VERY TOP – you can see a domed effect where the water molecules are holding together. That’s surface tension in action.

Surface tension is what gives wet sand its strength for great sandcastle building. The water molecules coat the grains of sand and hold them together, forming water-drop bridges in the gaps between the grains. Too little water, and surface tension can’t hold the sand grains together. Too much water, and the water turns into a lubricant and your sand collapses and flows with the water, making a mushy mess. 

We learned that the magic ratio of sand to water is about 8:1 – that is, 8 parts sand to 1 part water. The other key is making sure EVERY GRAIN of sand is coated with water to maximize the number and strength of those water-drop bridges holding the sand together. 

 By studying how and why sandcastles hold together, and how and when they collapse, we can better understand fields as diverse as civil engineering, physics and soil mechanics, among others.

Go to NASA to find out more about the physics of sandcastles.

Or go to PBS NEWS to see their castle making formula 1 bucket water to 5 buckets sand.

What is sand ? How is it formed - ask The National Ocean service they will give you an answer.

What about desert sand - how is that formed ?

Surprisingly little is known about the origin of the copious sand in the world's largest deserts. Research suggests that the Sahara Desert was once lush with vegetation before a change in climate turned it into a desert, part of which is covered in sand. On the other hand, the sand in the Namib desert in southern Africa may have been blown in by wind from the Orange River in South Africa ?