 |
|
|
 |
|
|
 |
|
|
|
|
|
|
Matter, and Physical and Chemical Changes
Miller Heights Elementary
School, Academic Year 2011-2012
Grade 1 |
|
|
|
|
| |
|
|
|
In this program, we learned what matter is made of and how it can change. We all knew that matter could be solid (like our desks), liquid (like milk), or gas (like the air). And, we even knew that water could be solid, liquid, or gas, depending on how hot or cold it is. If the Earth were too far from the Sun, all of the water on the Earth would be frozen into ice, like in our freezers. If the Earth were too close to the Sun, all of the water would boil and turn to steam, a gas. It’s a good thing that the Earth is just the right distance from the Sun so that most of the Earth’s water is liquid (though some of it is ice at the North and South poles).
|
|
|
|
| |
|
When water changes from solid to liquid or from liquid to gas, it is called a physical change. We learned that matter is made up of tiny objects called atoms. Atoms are so small that it took scientists thousands of years to even figure out that they existed. When the temperature is lower, the atoms move more slowly. So in a solid, such as ice, the atoms move slowly and stick tightly together. If you take an ice cube out of the freezer and let it warm up, the atoms begin to move more quickly. They are still close together, but now they can move enough to roll over one another, and we have a liquid. So, when you jump into a swimming pool (in the summer!), the water moves out of your way. Also, it can be poured and it takes the shape of the container you pour it into. If you place the water in a pan on the stove and make it real hot, the atoms become unstuck and zip all around the kitchen. Now, you have steam, which is a gas.
|
|
|
|
|
|
| |
|
|
|
Dr. DeLeo has a special machine that can make little metal balls move around between two pieces of glass. These moving balls help to show the differences between solids, liquids, and gases. When the machine is turned to "high," the balls bounce all over the little box, like atoms moving in a gas. When turned off so the little balls don't move, they all settle tightly together on the bottom. This is like a solid. When the machine is turned to low, so they only shake a little, they are close together like in a solid, but they can still roll over one another.
|
|
|
|
|
You can see these video clips if you go to the Odds and Ends section of this website and click on the items under "Phase Changes and Gas Pressure." Be sure to click your browser "back" button to come back to this page.
|
|
|
|
| |
|
Atoms are held together by electric forces. These are the same forces that hold a balloon on the wall. Many of us know that this is called static electricity. If it wasn't for these electrical forces, everything would just fly apart!
|
|
|
|
|
|
|
|
|
We learned that the air contains oxygen and nitrogen. We need oxygen to breathe. The air is mostly nitrogen. If we make nitrogen very cold, the atoms are pulled closer together by the electric forces, and it becomes a liquid. Liquid nitrogen is often used to make things very cold. If you dip a rubber band into liquid nitrogen, it becomes hard and brittle. We all got to dip rubber bands into liquid nitrogen, after we put on safety goggles and learned how to be careful. The liquid nitrogen is 300 degrees below zero!
|
|
|
|
| |
|
|
|
|
| Here are some pictures of us dipping our rubber bands in liquid nitrogen and breaking them. |
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
| Dr. DeLeo also poured some liquid nitrogen on the carpet, and he let us feel how cold it got. Click the play button on the picture just to the left to see to see a VIDEO of us touching the cold carpet. |
|
|
|
|
|
|
|
|
Although it looks like smoke in the photos above, the white vapor is more like clouds or fog. The liquid nitrogen vaporizes as it hits the carpet, turning back into the air it came from. But, the coldness causes the formation of tiny water droplets in the air, and these are clouds.
|
|
|
|
|
|
| |
|
|
|
Dr. DeLeo told us about a kind of matter that has very special properties when it is made very cold. And, one way to make things cold is to dip them in liquid nitrogen. The material has a long name - yttrium barium copper oxide. It is a ceramic, like pottery. But, when you make it very cold, it becomes a "superconductor." That means it conducts electricity perfectly. Another property of a superconductor is that a magnet will float in the air above it. Dr. DeLeo said that one day we may be riding on trains that float in the air using magnets and superconductors.
|
|
|
|
|
|
|
|
| |
| Dr. DeLeo dipped a racket ball into liquid nitrogen, cooling it to 300 degrees below zero. It was flexible and bouncy before he froze it. After he froze it, he threw it against the brick, and it shattered into pieces! We got to keep the pieces. Ms. T. took these great photos of the ball on the way to the wall. |
|
|
|
|
|
|
|
|
|
The photo below on the left shows the ball shattering against the brick, and the one in the middle is an enlargement of the one on the left. The photo on the right shows one of the pieces flying off to the side.
|
|
|
|
|
|
|
|
And... the camera continues to track that piece in the three photos below as it passes a sign and heads for the ground. Dr. DeLeo told Ms. T. that she was the best photographer he ever saw. By the way, Ms. T's real name is Ms. Tajdar!
|
|
|
|
|
|
| |
|
Click the play button on the VIDEO to the right to see the balls shatter. The video contains scenes from each of the three classes.
|
|
|
|
|
|
|
|
|
|
 Atoms can be put together in many different ways. When a few atoms are connected together, we call this a molecule. When we put hydrogen and oxygen together, we get water. A water molecule has two hydrogen atoms and one oxygen atom. It kind of looks like Mickey Mouse. A little bit of static electricity will bend a stream of water. We can use stronger electric forces by putting electricity into the water to pull the water molecules apart.
Before we did this, Dr. DeLeo talked to us about safety issues. He said that electricity and water are a dangerous combination. We should never take something that's plugged-in into water with us. We could get killed. Dr. DeLeo put electricity into water in a very controlled way, and we helped him by watching to make sure that his hands weren’t by the water when the electricity was turned on.
|
|
|
|
|
|
 When the electricity was on, bubbles rose in the water filled test tubes. Dr. DeLeo told us that this wasn’t the water boiling. The bubbles going into one tube were hydrogen, which is a gas. The bubbles going into the other tube were oxygen, which is also a gas. Dr. DeLeo had us ask him to prove that the gases were hydrogen and oxygen. He proved that the one tube contained hydrogen by holding a match by it. It went “POP!!" as the hydrogen exploded. The oxygen was trickier since it doesn’t burn. However, things don’t burn without it. That is why we “stop, drop, and roll” if we catch on fire – to smother the fire by cutting off its oxygen. Dr. DeLeo lit a thin piece of wood on fire, and then blew it out so it was only glowing red. When he placed the glowing wood into the pure oxygen in the test tube, it burst back into flames, over and over again. In pure oxygen, things burn better.
|
|
|
|
| |
|
|
|
|
| On the far left is a picture showing the oxygen bubbling up in the right test tube and the hydrogen in the left test tube. Notice that there is twice as much hydrogen. That's because water is H - TWO! - O. In the picture just to the left, Dr. DeLeo ignites the hydrogen with a match. |
|
|
|
| |
| Notice the hydrogen burning in the photo just to the right. And, less than a second later, a slight bit of flame is still seen in the test tube. (Actually, when hydrogen burns, it is clean and clear - the color is related to the gases from the burning match.) Once again, thank you for great photos Ms. T! |
|
|
|
|
|
|
|
| |
|
|
|
|
| The sequence of photos on the left shows what happens when the red-hot piece of wood is placed in the test tube of pure oxygen. Notice how it bursts back into flame. |
|
|
|
|
|
| |
| Even everyday matter, like water and air, can be amazing if you think about it. Dr. DeLeo gave us each a magnifier so we could explore the world more closely. What a great day! |
|
|
|
|
|
|
|
|
|
|
I hope you have enjoyed this web presentation as much as we enjoyed sharing the actual learning experience with your son or daughter. Although we have endeavored to exclude photographs where permission has been denied, it is possible for errors to occur. If you would like us to remove a photograph of your son or daughter for any reason, please send me an e-mail message at lgd0@lehigh.edu or call me at 610-758-3413, and we will remove it promptly. Please note that we will never associate a child's full or last name with a photograph except in circumstances where special permission was explicitly provided. Thank you. Gary DeLeo. |
|
|
|
|
|
|
|
|
