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Examining the World: From Very Small to Far Away
Asa Packer Elementary
School, Spring 2009
Grade 2 |
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Our world is filled with things that are very big and very small. Some of the very big things are very far away, like stars. Some of the very small things, like germs, can be very close. Our bodies are made up of many small parts that keep us alive. Dr. DeLeo showed us how glass shaped in a certain way, called a lens, can make small things look big when you look through it. We all knew that it was called a magnifying glass. He also told us that when we put two or more lenses together in just the right way, we can make a microscope, which makes really small things look big, or a telescope, which makes far away things appear to be close. |
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We went out into the hallway, and part way down the hall was a lit up Halloween pumpkin. Dr. DeLeo had a lens, like a magnifying glass, aimed at the lit up pumpkin. And, by us, he had a piece of paper, mounted so that it would catch the light passing through the lens. Can you guess what we saw on the piece of paper? We saw an image of the pumpkin, only it was up-side down! |
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| Dr. DeLeo told us that the light that goes through the bottom of the lens gets bent up, and the light that goes through the top gets bent down, so the top becomes the bottom and the bottom becomes the top, and the picture is ... upside down! Dr. DeLeo told us that this is how a camera lens works and the lens in our eye. Yes, the picture that gets projected to the back of our eyes is upside down! |
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Dr. DeLeo gave us 30-power hand held microscopes to use to examine all sorts of things in the classroom. After the time was up, he could hardly get us to stop. Here are some photos of us looking at things in the classroom. One of them shows what carpeting looks like close up. The carpet fibers look like worms! Another one shows the cover of a book. Look at how the colors are actually made up of different colored dots! Even the grown ups, students from Lehigh University, got interested in the microscopes! |
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Dr. DeLeo brought a powerful microscope that was connected to a television camera. The microscope is shown in the center picture below. He placed different things under the microscope and projected the picture on a screen. The picture on the left shows pollen grains. We all knew that they make your eyes water and your nose itch. Look at all the spikes sticking out of it. No wonder they bother us so much! Living things, like plants and people, are made up of cells. These cells come in different types - muscle cells, nerve cells, blood cells, ... The picture on the right shows human blood cells. |
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We learned that each cell can make other cells. A cell does that by dividing into two cells, each the same as the original. That's how we get bigger, and how our body heals itself when we get hurt. Every cell in any plant or animal contains instructions for making that plant or animal. So, every time a cell divides into two cells, the dividing cell has to make two copies of these instructions, one for each of the new cells. The instructions are contained in what are called chromosomes. |
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| The pictures on the right show the cells in a plant. Plant cells are kind of boxy looking. Some of the cells in the picture are in the process of dividing into two cells. The red arrow points to a cell which is dividing into two cells, and the stringy things are the chromosomes going into both of the new cells! |
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| Dr. DeLeo placed a dead bug under the microscope so it would look real big. It was really scary looking. We are sure glad that real bugs are not that big! A picture of the bug is shown just to the right. A video of us looking at the bug as Dr. DeLeo moved it around is shown on the far right. Click the play button on that picture to see the video |
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Even though many bugs are very small, they are still made up of many, many cells. However, there are some organisms that are made up of only one cell. Yes - The entire living organism is just one cell. This is amazing since the human body is made up of about 100,000,000,000,000 cells! |
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| A single cell organism that can be found in pond water is called a paramecium. They are so small that you need a microscope to see them. Dr. DeLeo placed live paramecia under the microscope for us to see. They swim around in a drop of water by moving little hairs along the outside of their bodies. Check out the videos on the left and right by clicking on the play buttons! |
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| Dr. DeLeo then took us by the front door of the school to look through a telescope. Since it was daytime, we couldn't see the moon or planets. But we did look at a tree that was very far away. Through the telescope, the tree looked like it was right next to us. The picture on the far right is a view through the telescope, showing new leaves just starting to grow from a small branch. |
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At the end of the program, Dr. DeLeo gave each of us a placemat with optical illusions. Now we can see how our brain can being fooled while we eat dinner! |
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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. |
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