VIBRATIONS AND SOUND

I love teaching sounds and vibrations but forget year to year how four hours of sounds a day can lead to a raging headache. Thanks to Motrin for getting me through the week. I didn't read the students a book as I usually begin class but instead downloaded an app for my IPhone called "100 Sounds". We talked about all of the sounds we learn and store in our brain. I then played about 20 sounds easy and hard and let the kids guess. They were very good at it and enjoyed it a lot. I began with sound being energy and that energy doesn't take up space. You can't blow up a balloon by placing it in front of a speaker and turning up the volume. Sound is energy like light and they don't take up space or aren't make of atoms and molecules. We compared sound and light. Light travels in straight lines. I shined a flashlight on a child and we noticed that it only reflected on the one person, the others were in the dark. Sound however travels in all directions in circle like a rock landing in a pond and making waves in all direction. Sound is faster in solids, then liquids and slowest in the air. Light is the opposite and is fastest in the air. Sound has to have matter to move. If you were on the moon and screamed there would be no sound because there's no air for it to travel through. Light however would be the fasted with no air. Light is much faster that sound and in a race light would travel around the earth in 1 second, sound would take 36 hours. People can't travel the speed of light but we can travel the speed of sound in a jet. I asked where sound would be faster, cold air or warm air? Cold air because the molecules are closer together.

Next we looked at sound waves. I made these out of rope. First I made a fast wave with the waves very close together and told them that this was a high frequency sound and we all made high sounds. Then I showed them waves far apart and we made low sounds. Next we made big waves these are loud sounds and small waves are soft sounds. People can hear sounds between 20 and 20,000 Hz. One hertz is one wave per second. Dolphins can hear at 200,000, bats at 120,000 and dogs at 80,000. Elephants can hear down to 8 hertz. I downloaded a free tone generator online and played low tones to high tones to see what the kids could hear. I used a tuning fork and placed it in water so they could see the effect of the vibrations. I then touched it to the kids noses so they could feel the vibrations.

Next I moved on to how the ear works. After showing them a picture of the inside of the ear I lined 3 kids shoulder to shoulder and told them they were the hammer, anvil and stirrup. I pretended to be a ear drum. I started vibrating and whacked into the "3 little bones" and they all crashed into each other. This stimulated the cochlea and a message is sent to the brain.

I then made sounds with a singing rod, running my finger around a piece of crystal, and cup with a sting through it with a sponge on the end. We finished with the wax paper around a comb and putting bolts in a balloon and having the kids spinning them to make vibration sounds. Each kid received a wooden slide whistle to decorate and take home.

Static Electricity

Static electricity is a fun class to teach. We begin talking about all of the ways we use electricity. The kids named all of the things they use (TV, computer, battery toys, etc...) I reviewed the atom by showing a picture and pointing out the electrons. The word electron sounds like the word electricty, that's because electrons jumping from atom to atom create electricity. Atoms in copper, aluminum and other metals move easily and are called conductors. Atoms in plastic, wood, glass, rubber etc have electrons that don't travel, these are called insulators.

Current electricity - I showed them a few kinds of batteries. Each battery is a box of electrons. There are 2 different metals inside the battery (electrodes) surrounded by an acid or base that dissolve the metals causing them to release the electrons. I asked if they've ever had a battery corrode inside of a toy. I had a 1.5, 6 and 9 volt battery and hooked each up to a light bulb one at a time. The 1.5 was dim the 6 volt was brighter because the electrons were coming out faster and the 9 volt was the brightest. Volts mean speed of electrons. We then all held hands and connected to light up an energy ball
(4.95). The electrons traveled through our hands to create a circuit. We then pretended to be a battery. I had to containers - 1 labeled positive and 1 negative. The faster we went the higher the volts. When we ran out of pompoms we said the battery had died and we could buy another or recharge it.

Static electricity - I have a Van der Graff generator to demonstrate static electricity and the kids love to have their hair stand up. You can use balloons to rub on their heads and transfer the electrons from the hair to the balloon.

For our projects each child got a 18 inch PVC pipe and put caps on the ends. We rubbed them with fleece and them picked up tissue paper, yarn and tinsel.

ATOMS AND MOLECULES

This week's lesson can be tricky to teach but even my preschoolers seemed to enjoy their new words they learned. I started with explaining that everything is made of atoms. The children then named one thing they could see that was made of atoms. I told them that atoms were so tiny that we couldn't see them and would have to have a very expensive electron scanning microscope to see them. They named things that they thought were tiny, ant, spiders, salt grains, germs, etc. I explained that the atom was tiny that any of these.

I brought out a tub of sand and asked the kids if they could count all of the grains in the tub. Could they count all of the grains on the beach? Of course not. That would e like counting all of the atoms in their body. Our bodies are made of Carbon, Hydrogen, Oxygen, Nitrogen, Calcium atoms with a Iron. I then gave each child 2 magnetic marbles that are 2 different colors. The yellow one was a proton which is positive. The lack one is a neutron which has no charge. I had a cup of tiny beads which are electrons - negative. I had a poster with a flat bowl in the middle for the nucleus and rings drawn for the orbits. I started with the smallest atom, hydrogen. One child dropped in a hydrogen and I put 1 electron on the shell. I explained that this wasn't a stable happy atom. If you inflated balloons with it, they would float but if they got to hot they would explode into fire balls. That's my hydrogen fuel sends the Space Shuttle into space. Then we added a proton and 2 neutrons and another electron to make helium. This is stable and won't explode if heated. We then made carbon (6 of each), oxygen (8) and calcium (20). I explained that if we made gold we'd have to put 89 of each onto the chart. I also explained that an atom isn't flat but is round and that the electron pop in and out very quickly in their shell. They pop in and out so quickly that they make a shell around the nucleus. This is like fan blades turning so fast that they look solid.

I passed out some Periodic Table of Elements that had pictures of what the elements are used for on it. The charts came from the American Chemical Society. I showed the kids gold and had them find it on the chart, then silver, aluminum, sulphur, iron, bismuth and zinc. The kids had fun pointing to different pictures and asking about them.

I have some magnesium powder purchased at a magic shop and when sprinkled over a candle sparkles. The kids recognized that fireworks are made from elements (atoms).

I then talked about combining 2 different atoms to make a molecule. Water is H20.
2 hydrogen and 1 oxygen atoms. Our breath is a molecule CO2. One carbon and 2 oxygen atoms.

Our last activity was tangling long skinny molecule (polymers) to make slime.

Our project was making an atom hat.

Fossils

This fossil class didn't include dinosaurs. I talked about fossils in North Carolina and prehistoric mammals. I have a great book with drawings of prehistoric mammals. I had a great book with pictures of Wooly Mammoths, Giant Sloths, Sabertooths, and more. I used Play Doug and small animal figures to show how the mold and cast type fossils are made. The children took turns pushing the animals into the "mud" to see what imprint or mold they would make. I used playfoam to demonstate replacement fossils. I made a bone shape and explained how water would wash away bit by bit leaving minerals behind. This is why their are many different colors of fossils. I showed the chidren my collection of petrified would that is many colored. The kids then identified some of my fossil collection and told me if they were mold or replacement. We then talked about the wierd fossils like the frozen wooly mammoths found around the Artic Circle. I had frozen some small wooly mammoths in ice cubes and let each child try to free them with there warm hands and craft sticks.

I purchased a shark's tooth for each child and helped them make them into a necklace.

Rocks and Minerals

What is the difference between a rock and mineral. Rocks are composed of minerals. How do you tell the difference between the two? Rocks and minerals are made by the earth. Bricks, concrete and glass are man made and not considered a rock/mineral. I showed the children a crystal grown from a kit and they thought it was real but I explained it wasn't grown in the earth. I had a string of pearls and asked if they were minerals. NO, they grew inside of a oyster/clam. Minerals have never been alive. Rocks such as chalk, limestone, petrified wood were alive at one time. Minerals have the same crystal shape throughout them. Quartz always had a hexagonal crystal. Mica has a flat Crystal. Halite - cube. Rocks can have many crystals in them. Granite is a good example to see. It has quart, mica and feldspar normally.

We went through some tests to help identify minerals. First was using your tongue. I have a huge piece of halite that I licked and then bought a box of rock salt and gave everyone a piece to lick. I then explained that you shouldn't go around licking minerals. I should them a piece of lead and explained how some minerals were poisonous. Next test uses the nose, I passed around pieces of sulfur. I had the kids sniff it and they all said it smelled like smoke and I explained that they use it in matches. Sulphur burns with a purple flame, but if you light it do it outside or in good ventilation because it smells bad. The next test uses our fingernails as we do the scratch test. I gave each child a piece of talc and let them scratch it and make powder like baby powder. I then gave them a piece of quartz and had them try to scratch it, it's a 7 on the MOH's scale of hardness the talc is 1. Diamond is a 10 and could scratch quartz. The last test we did was using a magnet to check samples to identify iron.

There are 3 types of rocks, sedimentary, igneous, and metamorphic. I explained that sedimentary is layered like a sandwich. I had a piece of sandstone that they could see the layers throughout. Igneous is fire rock and is hardened magma or lava. We pretended that a candle was a rock that I melted and we said that the melting wax was the lava. When the wax hardened it became "igneous rock". Pumice and granite are good examples. Metamorphic is rock that has been changed by heat and pressure of having a mountain on it. I had a multicolored pack of modeling clay. I gave each student a small ball and told them that they were a mineral. A rainstorm came and washed the "minerals" into the lake, which was my palm. The water squeezed these together to form a sedimentary rock. I showed them what it looked like stuck together. If I melted our "rock" it would harden into an igneous rock. I told the students that they were mountains and was going to squeeze the sedimentary rock and make it metamorphic. We passed it around and squeezed and saw how it changed. I then showed them limestone and the marble that it would change too after millions of years of pressure.

I had buried small mineral samples in sand and the kids glued the to the appropriate square on card stock.

Earthquakes and Volcanoes

The month of Geology is one of my favorite months to teach. I always start with the book HOW TO DIG A HOLE TO THE OTHER SIDE OF THE EARTH. I first explain that it is
impossible to dig through the earth. The book takes us through the layers of the earth. I use Playdough to build an earth. I use a magnet marble to act as the core. The core is silent iron and acts as to create a magnetic field in the earth. That's why a compass points north and why we have a north and south pole. The core is as hot as the surface of the sun and we pass it around and play hot potato. I then pass out pieces of yellow dough and have the kids put it around the core. This is the outer core. We placed on orange dough for the mantle (hot magma). We finished with flat pieces of brown dough to be the plates of the earth. When we finished I showed the kids where the pieces overlapped and made mountains and gaps where you can see the magma, where volcanoes form. I then cut the earth in half to show the kids the layers. I had a container of red jello which I called the magma and I floated graham crackers on top as plates. I showed them how the plates could float on this and cause earthquakes. I showed them a map of where the plate lines are and let the students see that we are in the middle of the plate and in a safe place. I had pairs of of wooden blocks with modeling clay on top. The children pulled on the blocks until the clay split causing an earthquake.

Volcanoes - I had drawings of shield, cone and strato volcanoes. I talked about the two types of lava, aa (slow, thick lava) pahohoe (fast, runny lava). We then looked a cross section of a volcano and looked at the parts. I then erupted one with baking soda, vinegar and soap. I also erupted one with ammonium dichromate. I burned it in a bottle cap on top of a volcano model. You can order the am. dichromate for around twelve dollars.

The students built clay volcanoes with a small test tube inside to take home.

DINO DIG

The last class in this month's series is Paleontology. The word fossil means "dug up". A fossil is the remains of any living organism. A paleontologist studies fossils and can specialize in different areas. Today's class will specialize in dinosaur fossils. I began with a book "BOY WERE WE WRONG". I sat the kids on the floor in a circle and brought out a plastic Stegosaurus and pretended that it was walking through the grasslands and it was older so it died. I asked them if they thought that it would become fossilized. Most kids said that it would. I then brought out a toy Allosaurus. I then acted out that the Allosaurus eating the Stegosaurus. For a dinosaur to become fossilized it had to become hidden from the predators. I had the students guess what could hide them. Sand storms, rock slides, quick sand, and floods were the favorite answers. Once the dinosaur was buried I asked which parts would become fossilized. The hard parts like the bones, spikes, teeth, and claws were what most kids think of. I added that skin prints, eggs, poops and footprints could be left behind too. I then moved on to showing the children the 2 groups of fossils. The first type is a replacement fossil. These are usually teeth, caws, bones, poops and eggs. The bone has tiny holes all over it and it lies in the dirt, water washes in and pushes a little of the bone out. Luckily it leaves a little piece of mineral in its place. I then passed around a T. Rex tooth replica. The second type is mold and cast which is footprints and skin prints. We pushed dinos into modeling clay to see the impressions left behind.

Next we went through what it would be like to work on a dig. First we'd go out west to Colorado, Utah or South Dakota where there are more dino remains than here in North Carolina. Then when we began to dig we'd photograph the cite, map the cite and as each fossil is removed we number it and mark the number on the map. The bones are wrapped in plaster wrap and transported to the museum or university to be cleaned, studied and reassembled. After digging a small T. Rex skeleton out of sand each student wrapped their bone with toilet paper and loaded into the back of a toy dump truck. We then drove the skeleton to the museum. Each child took a fossil package out and unwrapped it and we reassembled the skeleton.