Science – Beyond The Desk

How Quicksand Works

February 10, 2014 eoin24 Comments 0 Comment

With quicksand, the more you struggle in it the faster you will sink. If you just relax, your body will float in it because your body is less dense than the quicksand.

How many times have you watched a movie where the hero is sucked down into a pit of quicksand, only to be saved at the last minute by grabbing a nearby tree branch and pulling himself out?

If you believed what you saw in movies, you might think that quicksand is a living creature that can suck you down into a bottomless pit, never to be heard from again. But no — the actual properties of quicksand are not quite those portrayed in the movies.

Quicksand is not quite the fearsome force of nature that you sometimes see on the big screen. In fact, the treacherous grit is rarely deeper than a few feet.

It can occur almost anywhere if the right conditions are present. Quicksand is basically just ordinary sand that has been so saturated with water that the friction between sand particles is reduced. The resulting sand is a mushy mixture of sand and water that can no longer support any weight.

If you step into quicksand, it won’t suck you down. However, your movements will cause you to dig yourself deeper into it. In this article, you will learn just how quicksand forms, where it’s found and how you can escape its clutches if you find yourself hip-deep in it.

Next, we’ll find out how the ground shaking beneath your feet can lead to sand slipping beneath your weight.
What’s Quicksand?

Quicksand is an interesting natural phenomenon — it is actually solid ground that has been liquefied by a saturation of water. The “quick” refers to how easily the sand shifts when in this semiliquid state.

Quicksand is not a unique type of soil; it is usually just sand or another type of grainy soil. Quicksand is nothing more than a soupy mixture of sand and water. It can occur anywhere under the right conditions, according toDenise Dumouchelle, geologist with the United States Geological Survey (USGS).

Quicksand is created when water saturates an area of loose sand and the ordinary sand is agitated. When the water trapped in the batch of sand can’t escape, it creates liquefied soil that can no longer support weight. There are two ways in which sand can become agitated enough to create quicksand:

Flowing underground water – The force of the upward water flow opposes the force of gravity, causing the granules of sand to be more buoyant.
Earthquakes – The force of the shaking ground can increase the pressure of shallow groundwater, which liquefies sand and silt deposits. The liquefied surface loses strength, causing buildings or other objects on that surface to sink or fall over.

Vibration tends to enhance the quickness, so what is reasonably solid initially may become soft and then quick, according to Dr. Larry Barron of the New South Wales Geological Survey.

The vibration plus the water barrier reduces the friction between the sand particles and causes the sand to behave like a liquid. To understand quicksand, you have to understand the process of liquefaction. When soil liquefies, as with quicksand, it loses strength and behaves like a viscous liquid rather than a solid, according to the Utah Geological Survey. Liquefaction can cause buildings to sink significantly during earthquakes.

While quicksand can occur in almost any location where water is present, there are certain locations where it’s more prevalent. Places where quicksand is most likely to occur include:

Riverbanks
Beaches
Lake shorelines
Near underground springs
Marshes

The next time you’re at the beach, notice the difference in the sand as you stand on different parts of the beach that have varying levels of moisture. If you stand on the driest part of the beach, the sand holds you up just fine. The friction between the sand particles creates a stable surface to stand on.

If you move closer to the water, you’ll notice that the sand that is moderately wet is even more tightly packed than the dry sand. A moderate amount of water creates the capillary attraction that allows sand particles to clump together. This is what allows you to build sand castles.

But beach sand could easily become quicksand if enough water were thrust up through it. If an excessive amount of water flows through the sand, it forces the sand particles apart. This separation of particles causes the ground to loosen, and any mass on the sand will begin to sink through it. In the next section, you will find out how to save yourself if you happen to fall into a pit of quicksand.

My Experiment with Thinglink

October 12, 2013 eoin24 Comments 0 Comment

I found this cool site the other day called Thinglink which allows you to take a picture and add buttons on it. Thought I would try it out on this awesome picture I found about our universe. To find the hidden stuff, drag your mouse over the picture and you will see different dots show us. Click on the dots to see the videos or answer the questions.

What’s Up in Grade 4? (Psst! There’s Videos!)

October 10, 2013 eoin24 Comments 1 comment

So, I wanted to share some things that we have been doing in school lately. It’s been awhile and, while I am sure you have been hearing lots and lots about school at home (especially about my evil twin brother, Bob), I thought I would share some things with you. But don’t think that this is just for the parents. Au contraire, mon frere! Gather the kids and check it out!

In Language Arts, we have been doing a author study on the really cool and very interesting author, Chris Van Allsberg. He writes these fascinating books that are fantasy based. As part of this, we have been learning that fantasy books have three characteristics: they are usually based in the present, they take place in normal places but strange things happen and they have an element of magic in them like animals that talk. We have read a number of his books in class and have also talked about theme where the author writes a book to share a main idea. This is a tougher concept for the students to grasp as it is not very easily discerned. However, the books are a lot of fun with just enough of a twist to them to keep the kids interested. After the Thanksgiving break we will be starting our Home Reading program.

In Science, as you probably know, our class is doing a unit on Animal Habitats and Communities. As part of this unit, students are going to be assembling terrariums. The terrariums are homes for various plants and animals that typically live in or on the forest floor. Observing what happens in the terrariums gives students a chance to learn about the habitats and adaptations of animals that live in this type of environment as well as gain knowledge about the role these plants and animals play in the larger ecosystem.

We need your help in making this the best learning experience possible. Your child will need a variety of supplies in order to build their terrariums. The supplies they will need are inexpensive but I wanted to give you a heads up so you will have time to collect the items to send with your child. As you collect the items, you can send them with your child so they are ready to go once we begin to build the terrariums.

For Tuesday, Oct. 15th

Your child will need:

A small trowel
Boots
A small plant
Small amount of grass seed or birdseed
1 small plant such as strawberry plant, sweet alyssum, violets or other small garden plants which you can get fairly cheaply at Home depot, Walmart, Rona or a garden place.

We started today looking at the soil that your child brought in. We found some very cool things in the soil which were unexpected. We will talking more about soil and the importance of soil in the food chain, setting up an experiment with soil and starting our Terrarium habitats on Tuesday.

Here are some pictures from our look at soil:

Speaking of habitats, we have learned a lot about habitats and I found this cool video that I thought everyone would enjoy!

Finally, I found this awesome video on Science experiments you can do at home…and it has Oobleck in it!!! I don’t think you are ever too old for Sesame Street, especially when it’s done this way!

What Do You Mean, Pluto Isn’t A Planet?

September 12, 2013 eoin24 Comments 0 Comment

For the last couple of days, we have been scientists questioning, observing, and analyzing. It’s been a lot of fun and the students have had a great time doing some fun experiments including testing the flight of paper airplanes. Yesterday, we continued as scientists as we studied a mysterious substance found in my backyard, called Oobleck. This mysterious green substance has some very unique properties which we took some time exploring as you no doubt discovered when they came home covered in dust! It does wash out, I promise. We started by talking about what properties are and how we can observe the properties of objects. Then I showed them the Oobleck! Kids had a great time mucking around. In doing this, the students discovered that Oobleck was not quite what it initially appeared to be! After a few minutes, students took some time to write down 5 unique properties of this Oobleck.

Yesterday, we set up a scientific convention. Scientists all over the world get together in conventions to discuss and debate important scientific discoveries and questions to come to a consensus on various issues. Scientists use these conventions to come to an agreed upon truth about various scientific issues and thus are very important in the advance of science. The example I gave to the students was the scientific convention where scientists came to an agreement that Pluto was to be demoted to the category of dwarf planet and was not to be in the same category as our other planets. There was a huge debate and lots of arguing but at the end of the day, scientists had come together and agreed to change Science.

So we had our own little convention today to come up with some truths about this mysterious substance. It was a great time arguing and voting. The kids came up with some great points. Here are some pictures from the convention:

We’re going to be doing some neat things in the next couple of days in Science so keep an eye out here for more news! In the meantime, here is a nice video by one of my favorite scientists, Bill Nye, talking about why Pluto isn’t a planet.

Also, I found this great article with pictures showing what we would see in our night sky if the other planets in the Solar System were as close as our Moon is to Earth. The first one is Mars:

Our moon is a pretty big object. It’s big enough to be a respectable planet in its own right, if it were orbiting the sun instead of the Earth. (Actually, it is orbiting the sun in a nearly perfectly circular orbit, that the Earth only slightly perturbs… but that’s a topic for another day.) The Moon is a quarter the diameter of the Earth. Only Pluto has a satellite that is larger, in proportion to the size of the planet it orbits.

But what if the Moon were size of Mars, instead? It would like the picture above. Check out how some of the other planets of the Solar System would look in our sky, if they took the Moon’s place.