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.

Nitrogen is found throughout the soils and atmosphere in many different, organic and inorganic, forms. The Nitrogen Cycle is the process by which atmospheric nitrogen  enters the soil, is transformed by microbes, and re-enters the atmosphere (volatilization) and plants (assimilation).

How Does Nitrogen Enter the Soil?

Before nitrogen can be used by plants, it must enter the soil.  Atmospheric nitrogen is forced to the ground by rainfall. Also, urine, solid and liquid waste from living organisms and living organisms that have died are deomposed by bacteria and fungi.  The nitrogen from these sources then enter the soil. Commercial fertilizers are another source of nitrogen.

What Happens to Nitrogen in the Soil?

Plants cannot use organic nitrogen. Bacteria and fungi are needed to transform this unusable organic nitrogen into a usable form.  Although most nitrogen fixation is completed by bacteria, some is accomplished through lightning strikes. Since ammonia is fatal to most plants, bacteria convert this ammonia (NH4) into nitrates (NO3) and nitrites (NO2). At this time, the nitrogen can be assimilated into the plant, leached into the ground water or be transformed into a gas and re-enter the air.

In very wet soils, the oxygen content is low. The bacteria in these soils take the oxygen out of the nitrates (NO3) and produce nitrogen gas. This process is call denitrification.  Through a process called volatilization, the gas re-enters the atmosphere.

Dissecting owl pellets is a fun and educational method of analyzing predator / prey relationships and for learning basic dissection techniques.

What is an Owl Pellet?

An owl pellet is the portion of an owl’s prey that has not been digested. Owl’s swallow their prey whole (they don’t have teeth to chew) and the feather’s, fur, bones and other undigestible parts are regurgitated by the owl.

How Does the Owl Pellet Form?

When the prey is swallowed, it travels through the esophagus and into the first part of the stomach, the proventriculus. Unlike other birds, the owl does not have a crop to store the food. As a result, the prey enters directly into the digestive tract. This part of the stomach has enzymes and acids (like our stomachs) to aid in digestion. From the proventriculus, the food travels to the second part of the stomach, the gizzard. The gizzard is a muscular organ that grinds the food and ”filters” undigestible parts from traveling into the intestines.

The pellet is formed from the hair, bones or feathers that are left in the gizzard. The pellet will take several hours to form and several more before it is regurgitated. The owl cannot eat again until this pellet is expelled.

Does the Regurgitation of the Pellet Benefit the Owl?

Yes.  Many scientists believe that this regurgitation of the pellet keeps the upper digestive tract clean.

See the Oxygen molecules bubble and the indicator turn pink

Hydrolysis Water Splitting
Using a 9V battery, 2 electrodes and small gauge wire, you can split water into its component parts. This process is called hydrolysis. We add a small amount of salt to increase the conductivity of the water and an acid/base indicator to visualize the reaction.

The chemical formula of water is H2O. When the electrical current, produced by the battery, passes through the water,  the water will split and the two electrodes will bubble. Hydrogen will appear at the cathode and the oxygen at the anode. The acid base indicator around the cathode will turn blue (because the free OH molecules raise the pH) and the area around the anode will turn pink (because the free hydrogen molecules lower the pH).

Looking at the formula for water, there are twice as many hydrogen atoms as oxygen. When hydrolysis occurs, twice as many hydrogen bubbles will be released as oxygen. You can visually see extra bubbles at the point where hydrogen is being released.

Hydrolysis experiments can be quantitative (how much hydrogen and oxygen are released?) or qualitative (can I visually see the reaction taking place?)

Keep the lid over your plate to prevent contamination.

All living organisms require energy. They can get their energy from multiple sources: organic chemicals(carbon containing compounds), inorganic chemicals and light. Bacteria use organic chemicals, such as, sugars, starch, protiens and fats to grow. Bacteria are called heterotrophs.

Most bacteria grow best at normal, human body temperature (98-99 degrees F). When growing the bacteria, incubate at a temperature as close to this as possible. The bacteria will grow slower at lower temperatures.

Aseptic technique is the process of growing and transferring bacteria without contaminating the culture by touching or breathing on the sample.

Nutrient agar is a general purpose prepared media and grows many types of bacteria and fungi. If you have a specific bacteria culture, you can spread the bacteria on the plate using a sterile swab or innoculating loop. The bacteria will grow and become visible in 24-48 hrs. If you would like to determine the types of bacteria growing on a sink, chair, table or other areas, a sterile swab can be used to rub across the area you would like to test. After the sample is taken, you can transfer the bacteria to the nutrient agar plate by swiping the swab across the surface of the agar plate. After 24-48 hrs, you may find many, different looking colonies growing on the nutrient agar plate. Each type of bacteria look a little different (color, shape, size) when they grow.

Bacteria can be differentiated based on how they react to a a procedure of dying cells called Gram stain. Bacteria are divided into a group that turns purple (gram positive) and a group that turns red (gram negative). Bacteria that are gram (+) include Staphylococcs, Streptococcus, Bacillus and Micrococcus. Gram (-) bacteria include E.coli and Salmonella. The Gram staining procedure is as follows:

Gram Staining Bacteria Procedure
1.Place a drop of distilled water on a slide and, using a swab or inoculating loop, mix the bacteria with the water an smear the mixture on the slide. The mixture will appear cloudy. Using a flame, heat fix the bacteria to the slide (pass the slide through the flame a few times to “dry” the bacteria and affix it to the slide).

2. Using a dropper, add crystal violet to the slide. Let stand for 1 minute.

3. Add iodine to the slide. Let stand for 3 minutes.

4. Decolorize the sample with alcohol. Let stand for 30 seconds.

5. Counter stain the sample with safranin. Let stand 1-2 minutes. Using a dropper, rinse with distilled water.
Gram Staining Results
Gram positive bacteria will appear purple under the microscope. They have a single, thick cell wall. The crystal violet and iodine combine to attach to this wall. The decolorizer (alcohol) dehydrates the cell wall, causing the pores to close, trapping the stain inside. the safranin added in the final step, does not penetrate the wall.

Gram negative bacteria will appear red. The have a cell wall and additional thin layers of fatty sugars. The decolorizer easily penetrates these thin sugar layers, washing away the crystal violet – iodine chemical (purple color). The safranin in the last step attaches to these layers and appears red.

This post takes a look at the Hydro-Splitter Kit offered by Heath Scientific. The Hydro-Splitter Kit is a science fair project for kids that educates them about electricity and the electrolysis of water.

Other projects similar to the Hydro-Splitter are also available from the Heath Scientific website. The website offers science supplies as well as other science projects cover a wide range of topics from carbon to light and optics kits. These kits offer a cost effective way for parents to enrich their children’s minds while having fun at the same time.

General Information

Water is made up of twice as many hydrogen molecules as oxygen molecules; this is why the chemical formula is H2O. Electricity breaks this formula down when introduced into water. The molecules split with hydrogen appearing at the cathode and the oxygen will mix with one hydrogen molecule making hydroxide.

Supplies Needed

- 1 Beaker
- 2 Carbon Rod Electrodes
- 1 Acid/Base Indicator
- 3 Alligator Clip Wires
- Salt
- 2 Droppers
- 9 Volt Battery- not included in the Hydro-Splitter Kit

Experiment Procedure

The carbon rod electrodes are connected to the battery with the alligator clip wires. Fill the beaker with 200 milliliters of water along with 25 drops of acid/base indicator and a pinch of salt. Adding a second 9 Volt battery can increase the speed of the reaction.

Results

There will be more hydrogen molecules than oxygen in the water and the electrode that the hydrogen is drawn to will have more bubbles. The water around this electrode will be blue; the water around the other electrode where the oxygen is drawn will be pink. This kit allows for a cost effective way to explain the concepts of electricity and voltage.

Founded by Pat and Heath Nichols, Heath Scientific is a provider of educational supplies located in Cedar Hill, Texas. Major suppliers of Heath Scientific include AntWorks, Thames & Kosmos, Uncle Milton, and Can You Imagine. If you are interested in hosting a school fundraiser, or obtaining science related educational tools, contact Heath Nichols at Heath Scientific by email at heath@heathscientific.net or by phone at (972) 291-4223.