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.