Teaching Chemical Changes in the Elementary Classroom

Sodium Bicarbonate, Calcium Chloride and Phenol Red

Let’s go over the procedure first and then we will discuss what is happening.

1. In a quart baggie, place sodium bicarbonate(1 tsp) in one corner and calcium chloride(1 tsp) in the other.
2. Lay the bag on its side and place a small cup (medicine cup size – 1 oz) of phenol red in center of the bag. Be careful not allow the any on the chemicals to mix yet. Seal the bag
3. Gently pour the phenol red where it spills into each corner. Do not mix the two corners yet.
4. Have the students feel each corner and make observations. Continue the observations for a few minutes.
5. Pick the bag up and gently move the bage side to side, mixing the chemicals. What happens?

Explanation

The side of the bag with calcium chloride becomes warm. The calcium chloride dissolves forming calcium and chloride ions. The release of heat (exothermic) is a result of the calcium chloride dissolving and not a chemical reaction.

When the sodium bicarbonate dissolves to form sodium, hydrogen and carbonate. It becomes cool (endothermic). The baking soda absorbs heat in order to dissolve. This is not a chemical change.

When the two sides are mixed, calcium carbonate is formed which is insoluble. Also formed are water and carbon dioxide. The carbon dioxide (gas) causes the bag to inflate. When the carbon dioxide dissolves in the liquid, carbonic acid is formed. This change in pH causes the phenol red to turn yellow. A chemical change has now occurred.

Remember to have the students use all lab safety measures. If the bag becomes over inflated, release some of the gas.

Teaching Wind Power

The interest in renewable energy has increased greatly. The US currently produces enough wind energy to power 14 million homes. Approximately 2% of our energy comes from wnd, which is double from just 3 years ago. many beleive that in 2030, 15-20% of our energy will come from wind.

The reason for the growth is partially associated with new government regulations concerning our impact on the environment. Federal and local governments are receiving pressure from voters to find alternative sources. Experts believe that if the 2030 scenerio occurs, we would reduce carbon dioxide emissions by 7600 metric tons and create 200,000 jobs.

Windmills have been around for centuries to pump water and grind seeds into grain. A wind turbine is an advancement that turns an electrical generator. The force of the wind, turns the blades. the rotor turns and spins a driveshaft that is connected to an generator. the generator converts this mechanical energy in to electrical energy.

There are several variables that determine the amount of energy produced: wind speed, diameter of the rotor, density of the air, and efficiency of the turbine.

A great product for teaching wind power concepts is the Basic Turbine. The Basic Turbine is a great start for teaching about wind energy in the classroom. Visit www.heathscientific.net to purchase this item. This is the most affordable and robust wind turbine kit on the market. Design blades and test your power output with a multimeter, LED bulbs, or an ultra capacitor.

The instructions that are included will show you how to build this PVC turbine, how to make blades for your wind turbine, how to use a multimeter to record electrical data and will discuss some basic wind energy science.

Fundraising for the Science Classroom

In School Science Store

With the reduction in state funds, the need to raise money through other methods has become even more important. Science is a subject that can’t be fully appreciated when limited to text books and worksheets. One of the keys to teaching young students is camoflage. When the student is engaged, enjoying the activity, creating and problem solving, they forget that they are supposed to be learning. These instances are where some of the greatest lessons are learned.

When approached properly, science is easy to make interesting……but it isn’t free. The students benefit greatly from using real science equipment, beakers….graduated cylinders…microscopes….live animals…pipets and test tubes. As educators, one goal should be to create young scientists and prepare them for the world they will find.

I often hear that “My school can’t afford these items.” With some hard work, outfitting a science lab can be achieved. Heath Scientific has been providing fundraising options to teachers, PTO’s and school organizations for 10 years. Create excitement and interest in your science program by setting up an Exploration Fair. Your school will ask volunteers (parents are great resources) to help run a retail store for a week. The store has science experiments, rocks, fossils and educational toys that excite the students and raise funds for your school.

Set up an online store at error and encourage students and parents to visit the site for birthday and christmas presents or for science fair projects. The items are shipped directly to the customer and you do not have to distribute any merchandise. Your organization receives a percentage of all sales.

Heath Scientific also provides bulk packages that allows your organization to make up to 80% profits. Use the profits earned to buy real science equipment that can be used for many years.

Don’t let money stop you from providing your students a top notch science classroom.

Glacial Heat – Teaching Supersaturated and Supercooled Solutions

Glacial Heat

Glacial Heat

What’s Happening?

Inside the Glacial Heat exists a supersaturated and super-cooled (below its freezing point) solution of sodium acetate and water.This supersaturated solution was created by mixing the salt (sodium acetate) in hot water. Hot liquid will dissolve more salt than a cold one. When this solution is cooled slowly, the salt stays in solution.

CH3COONa.3H2O + Heat -> CH3COO-(aq) + Na+(aq)+3H2O
(Solid) (Liquid)
A small, stainless steel, metal chip provides the “spark”. When the chip is squeezed, a small, single, solid salt molecule is created. This is the seed ,on which, the other salt crystals begin to form. The normal freezing point for sodium acetate is 130 degrees F (54 degrees C). The reaction occurs quickly, with heat being released and the liquid becomes solid (freezes). The heat being released is equal to the freezing point of the solution (54 degrees C). The sodium acetate (a salt) dissolving and freezing in the water is an example of a physical change.

 

How do I Teach With Glacial Heat?

Discuss physical and chemical properties:

Physical properties are observable (color, size, luster and smell) and also include characteristics, such as, freezing point, melting point, malleability, conductivity, volume, mass, weight and length.

Chemical properties are only observable during a chemical reaction and can include flammability or the ability to rust. In each of these examples, a new compound has been formed.

Discuss physical and chemical changes:

Physical changes include ice melting, molding clay, water evaporating, a coke freezing and sugar dissolving in water. In these examples, no chemical changes have occurred and the changes can be reversed.

Chemical changes include metal rusting, lighting a match, milk souring and the stomach digesting food. These changes are not easily reversed. The presence of light, color change, odor, gas production, heat or sound can indicate that a chemical change has taken place.

The Glacial Heat can be boiled (melted) for 7-10 minutes and reused over and over again.

Teaching the Carbon Cycle

The carbon cycle is the process by which carbon enters and exits the earth’s atmosphere. Carbon, in the form of carbon dioxide, and along with other gases, acts as a warming layer for Earth. Without this layer of gases, the Earth would be too cold to sustain life. There are many carbon cycle models and carbon cycle demonstration kits available to assist in the explanation of this process. Below is a basic explanation of the carbon cycle.

The Carbon Cycle

Carbon is released into the environment in many ways. Animals and plants respire, releasing carbon dioxide into the atmosphere. Animals release solid waste products into the soil and water. Also, leaves, roots, wood and dead animals decay. Finally, the burning of fossil fuels and wood release stored carbon into the atmosphere.

The carbon that is released into the environment, is used by many plants and animals. This is the part of the carbon cycle that removes carbon from the atmosphere. Plants and algae take in carbon dioxide during photosynthesis. Many sea creatures take in carbon when making shells and bones. When these animals die and sink to the ocean floor, this carbon is stored for some time.

The Ocean’s Role

The majority of photosynthesis occurs in the oceans by algae and phytoplankton. Also, due to the large surface area of the oceans , carbon dioxide diffuses in and out in an attempt to equalize.