February 2018

A short, yet full month, was the month of February.

Science Fair

We carried out, wrote up, rehearsed and presented two science fair projects. Both were about electricity.

To introduce the concept of electrical charge we carried out a few experiments:

1. I built a simple electroscope- a glass jar, a self-made lid from foam, a small hole in the center of the foam, a metal piece from a paper clip, and two light pieces of aluminum . We charged a balloon by rubbing it against hair, and introduced the charged balloon to the jar. The effect was that the two aluminum pieces separated. 
2. We charged a balloon and were also able to move from a distance, through induction, an empty can. 
3. We inflated two identical balloons. We tied them with a string of the same length. We taped the balloons to the ceiling. We placed a small magnet between the balloons. The balloons separated.  

The eight-year-old's science fair was about Batteries connected in Series. He learned about the inner workings of batteries, the components and their dependencies; as well as the basic principles of current flow. I explained that a battery is a device which pushes electrons around a circuit; it is a device that does work. We carried out six experiments:

1. The first one was using regular batteries. We connected them in series, adding them one by one and measuring the voltage every time.
2. The second on was by building a Penny-Salt-Nickel battery units and stacking them on top of one another. As we would add a new battery unit we would record the new voltage. This was the most successful battery combination; ten battery units produced 3V.
3. The third experiment was the same as above, except that we excluded the salt water bridge (we did not put the paper between the Penny and the Nickel. No voltage was produced. This highlighted the important of the bridge which I spent a good deal explaining.
4. The fourth experiment was to build a lemon battery. On each lemon with a knife a small slit was made; in one slit was placed the Penny, and in the other slit was placed the Nickel. The batteries were connected one by one and the voltage was measured. We barely got 1 V out of 3 batteries.
5. The fifth experiment was to cut one of the lemon battery units in half between the coin slits. No voltage was measured because the circuit was open and no current was flowing and no work was being done.
6. The sixth experiment consisted of him putting one half of the lemon on one palm, and the other half of the lemon in the other palm. The result was a closed circuit and voltage was measured. The importance of this last experiment was to highlight that the human body can conduct current, and one needs to be very careful when handling electrical components.

The ten-year-olds' science fair project was about Ohm's Law. We verified it by using a solderless breadboard, resistors of different resistivity, and 9-V battery. She learned a lot of concepts.

1. What a resistor is, why it is important in a circuit, and how to read and measure its resistivity.
2. What current is and how to measure current flow in a circuit.
3. What voltage is and how to measure it across a component in a circuit. In addition she participated in the boy's science fair, so she learned in detail what batteries are and how they work.
4. We measured the current as we were changing the resistors. We verified Ohm's formula and talked about why it makes sense. The higher the resistor, the more work the battery needs to do in order to push the electrons through; the more the electrons to be pushed through, the higher the work the battery has to do.
5. We also hooked up an LED to the circuit, after we had carried out the previous step. This showed the effect of increasing the voltage through the current-the higher the resistance, the lower the light intensity.

New York Trip

We were in New York for three days. I had to go for work, and the kids stayed with relatives. They met their big sister, they nephew, and other family members. They had a good time. We visited the National Museum of Math. We had a lovely experience there but had to leave because we were hungry. The trip back was an adventure. It took us forever to leave; the delay was due to bad weather. We also almost missed the flight because in my mind I was running an hour behind, but once I saw people lining up at our gate, we rushed for it, and succeeded to board on time, and pick good seats.

Books and Reading

We slacked here a little because of the travel and because of family's visit, but we did read. We read most of the Native American tribe stories. We watched the map for each of the nations. We also watched the Trail of Tears. This saddened the kids but they realized why I am not head over heels with the American History told in schools. We have the Sioux, Seminoles and Iroquois to talk about and then we will move to African American history.