ALVORD EXL STEM 1

Welcome to Alvord ExL STEM 1!

PLEASE NOTE:

  

Guide students in building and experimenting with Brush Bot as per instructions.

How does the Brush Bot Work?

This bot builds on the concept of “Eccentric Rotation.” A motor with an “eccentric wheel” (unbalanced wheel), shakes wildly when rotating. The elasticity of the plastic bristles transforms the force of the unbalanced rotation of the motor to move the bot forward and around. The type of surface determines the speed of the bot and its behavior.

Conduct your own experiments to find out more!

EXPERIMENTS:

1. Experiment with changing the direction of the brush’s bristles? Can you control the behavior of the bot?
2. How do different surfaces affect the bot’s movement? Why do you think that is?
3. How does “friction” figure into all these experiments?
4. What other experiments can you come up with?
5. Can you calculate the speed of your bot? You will need a measuring tape and a timer. Your speed can then be expressed as distance/duration, just like mph (miles per hour). In our case it will be more like inches per seconds, for example. Advanced math wizards can probably take this a few steps further and express the speed in miles per hour.

  

Follow the directions on the instruction sheet and guide students in the building of the Walking Bot. Explore the science behind the bot:

How does the Walking Bot Work?

Upon completion of the bot, engage students in the following experiments:

EXPERIMENTS: 

1. Experiment with re-aligning the half-circle foam pieces? How does it affect the bot’s movement? Try different combinations. 
2. How does switching the motor wires affect the movement of the bot? 
3. How do different surfaces affect the bot’s movement? Why do you think that is? 
4. How does “friction” figure into all these experiments? 
5. What other experiments can you come up with? 
6. Try making the bot climb up an incline. At what point is the bot unable to move forward? 
7. Try making the bot walk down an incline. What observations can you make? 
8. What does the switch do? How do you think it works?

    

Guide students in the building of this bot, which is more complicated due to more building steps, small screws, etc. This bot should also be explored in class as an art tool, as it draws circles patterns. Make sure to ask classroom teachers to provide a sheet of paper for students so they can experiment drawing with the bot. Make sure to also tell students NOT to remove the caps from the felt pens, unless the bot is placed on a piece of paper.

Science behind the Drawing Bot

How does the Drawing Bot Work?
This bot builds on the concept of “Eccentric Rotation.” The rocker applies an “unbalanced weight” on the motor shaft, thereby causing the motor to shake wildly while rotating. Eccentric, means “out of the center”. Without the unbalanced weight on the shaft, the motor would hum along quietly without shaking, as the shaft would be “centered”. With the rocker, the shaft is “out of the center”. The rocking motion is utilized to move the bot in a circular motion. By adding felt markers as “legs”, the bot is able to draw its movements on paper. Enjoy!

EXPERIMENTS: 

1. Experiment with switching the motor wires. How does it affect the bot’s drawing? 
2. Why is the motor placed inside a foam motor mount? 
3. What do you think will happen when placing the brackets (and markers) at different angles on the propeller plate? How would it affect the drawing? 
4. How does using different types of paper affect the bot’s ability to draw? Why? 
5. What other experiments can you come up with? 
6. What does the switch do? How do you think it works?

Welcome to Our Sun!

Invite students to share what they already know about the sun.
What is the sun? How do we on earth benefit from the sun? Where is the sun? How far away is the sun from planet earth?

Facts about the Sun
The sun is amazing. Without it, none of us would be here, and there would be no life on earth. It is bigger than anything we can really imagine--a million planet earths would fit inside it! It takes millions of years for the energy from the center of the sun to reach the sun's surface, and then just eight minutes for it to travel the 93 million miles to earth! The sun gives off more energy in one second than people have used since the beginning of time.

But wait, there's more!
Plants make food using sunlight, and then animals eat plants, and so on. Without sunlight, plants couldn't make food, and there would be nothing for us to eat. Not only could plants not make food without the sun, they also couldn't make oxygen, and no animals could breathe, including us! 

The sun produces nearly all the heat on the planet, too. Without it, the earth would be freezing cold--minus hundreds of degrees Fahrenheit, almost as cold as space. The sun also makes the wind blow and the ocean currents flow. Its heat makes clouds, rain, snow, and all the weather on our planet, too.

OPTIONAL RESOURCE: Use only the first 5 minutes of this video to visually explore facts about the sun.

  

What is Solar Energy?

Solar energy is a term that includes any and all energy that comes from the sun, i.e. heat and light.

There are countless ways we can use and have used solar energy. The simplest way is using the heat that the sun provides, also referred to Solar Thermal Energy.

Solar Thermal Energy

If you have ever left a garden hose lying in the sun, you will know how hot the water can get when you turn on the faucet to run water. Similarly, many buildings have piping on the roofs to collect the heat of the sun and warm up the water flowing through them to create hot water for kitchens, showers, etc. Simply letting sunlight shine through your window on a cool day will warm up your room.

These types of Solar Thermal Energy applications work best with objects that absorb or take in most of the heat energy rather than objects that reflect or do not take in most of the heat energy.

Class Discussion:
Objects of different colors absorb (or take in) and reflect (or send back) light and heat. Who knows what color absorbs the most energy/heat? Which color absorbs the least amount of heat and energy?

Solar Thermal  Energy is used as part of  solar thermal power plants, which collect the sun's heat to create steam, which then turns an electric generator turbine and produces electricity. (Fossil fuel burning power plants also produce electricity by first creating steam in order to turn a turbine.)

Another very simple application of concentrating the sun’s heat energy is a solar cooker..

What is a Solar Cooker?

In the United States the stoves in our houses run on electricity or gas. In other parts of the world many people still cook over campfires. One of the many cool things about solar cookers or solar ovens is that they don't need electricity, gas, or wood to work. They cook food using only sunlight! 

Basically, you put food into a box and trap the sun's heat by covering the box with clear glass or plastic.  To help absorb the sun's heat, the inside of the box is black. Aluminum foil flaps on the outside of the box help reflect sun light into the box, adding even more energy. Even a simple solar cooker like this one can reach temperatures over 250? F.

  

Using solar panels to turn the sun's light directly into electricity is new. This technology was invented only about 50 years or so ago, and recent improvements have made this technology very efficient.

How do solar electric panels work?

Solar electric panels, as they are referred to, are made up of something called silicon, the same material that makes up sand. There is more silicon on this planet than almost anything else. Even though you can find silicon almost everywhere, making a solar panel is difficult and expensive. The silicon has to be heated to super high temperatures, and then formed into very thin wafers.

When sunlight hits a solar panel, it makes electrons within in the silicon move  around. (Electrons are very tiny --they are too small for us to see, even under a microscope.) The electrons flow through wires that were built into the solar panel. And presto - We have electricity! 

Solar panels are also called photovoltaic panels. "Photo" means light and "voltaic" refers to electricity (volts).

Our building kit contains the materials for a solar car. Once completed the energy from the sun will allow the electric motor to turn and move the car.

Lets get started!

Click on the link above and use this slide show to guide students in the building process. 

Please note: parts are very small and instructions need to be followed completely to successfully create the solar car project.