Teaching Parallel Circuits to Your Students


To start, we need to define current and voltage:

  • Current is the rate (or speed) at which the electrons are flowing through the circuit and is measured in amperes (Amps).
  • Voltage is technically the electrical potential difference between the beginning and end of a circuit….or simply, the force at which the current travels through the circuit. Voltage is measured in Volts (joules/coulomb).

We are going to start with the simple circuit we created in a previous post (connect the alligator clip to negative side of battery, then connect to knife switch, knife switch to lamp holder, lamp holder to positive side of battery).

Now let’s make some modifications and create a parallel circuit. In a parallel circuit, the voltage stays constant in each branch of the circuit.

Creating a Parallel Circuit

Using our simple circuit with the knife switch in the upright position, we are going to add another load (light) and create a parallel circuit.

  1. Take a wire with alligator clips and attach to one side of the existing lamp holder.
  2. Using a separate wire, attach one end to the other side of the existing lamp holder (*note: there will be 2 clips attached to each side of the existing lamp holder).
  3. Take the ends of the two wires that are free and clip one to each side of a new lamp holder with light bulb. When the knife switch is closed, both lights illuminate.

In a parallel circuit, the voltage stays constant in each branch of the circuit. So, using a 1.5V battery, both bulbs are receiving 1.5V of electricity. This is the reason both light bulbs have the same brightness. If you measured the current, you will find that the current is divided into each branch. Therefore, if 10 amps of current were flowing through the circuit, each light (or branch of the parallel circuit) would be receiving 5 amps of electricity. Adding the amount of current in each branch together, will give the total amount of current introduced into the circuit.

Heath Scientific has a kit called “Making Circuits Simple.” This kit has all you need to complete this experiment.

Explanation of Color From a Prism

Although no one knows who invented the prism, Sir Isaac Newton was the one who discovered that the rainbows they produced were merely the components of white light that had been separated.

What is White Light?

Usually just called light or “visible light,” white light comes from the sun. It can also be produced by incandescent light bulbs, fires, or anything that gets hot enough to emit visible light.

How White Light becomes a Rainbow

When light shines through a prism it enters at an angle and exits at another angle. Different frequencies (color) of light are refracted at slightly different angles when they enter and exit the prism at an angle. Refraction is the change of direction that occurs when any type of wave goes into a different material at an angle.

Because the diffraction angle is different for different colors, the white light gets separated into different colors as it passes in and out of the prism.

What Colors come from a Prism

Although people can perceive around 10 million colors, prism colors are classified as one of the following seven:

  1.    Red
  2.    Orange
  3.    Yellow
  4.    Green
  5.    Blue
  6.    Indigo
  7.    Violet

How to get a Bigger Colors from a Prism

The further away the prism is from the target surface, the larger but also dimmer the colors will be. If you have a dark room and a bright sun, it will show up beautifully at a distant wall.

The closer to the prism the more brighter and bunched up the colors become. If you get too close to the prism then you will not be able to distinguish the colors anymore.

Color Lessons for Children

Catch the Rainbow.

Younger children love to chase the rainbow along the wall and around the room as you tilt the prism. They will try to catch the rainbow in their hands.

Share observations.

Children of all ages can make observations of the prism’s rainbow. Preschool children, like the 2- and 4-year-old pictured here can describe what they see. Ask if they hear, smell, or feel the rainbow.

For older children, ask if the colors are in separate bands or if they run together. Is each color equally wide, or are some wider than others?

Color what you see.

Have the prism shine onto a table or other solid surface, provide a variety of crayons and have them color what they see or color around it.

Test different light sources.

Try a strand of colored Christmas lights–what colors come out of the prism? What about that yellowish light in the lamp? Or a black light?

If using Sunlight

Keep in mind that the earth is rotating, so if you are using sunlight the color will move and you may have to readjust the prism for maximum color and shape.

Related Products

4″ Prism
Diffraction Gratings

Other Resources

What is White Light
Spectrum from Prism

How to activate and reuse Glacial Heat


Glacial Heat, commonly known as hot ice, is easy to use.
Bend or flex the metal disc in the Glacial Heat pack. Instantly, ice will form on the disc and spread through the pack. You will feel the pack get warm. It should stay warm for at least half an hour.

The pack remains frozen at room temperature until you prepare it for reuse.


To reuse the pack, put it in boiling water for about 10 minutes. I recommend medium heat on your stovetop. You might smell a slight odor of plastic–that’s okay. Flip the pack in the water while heating to avoid melting the rubberized cover.

Take the Glacial Heat pack out of the water after all the crystals are gone and let it cool. Once it cools completely, it is ready for use.

Video instructions

The science

Curious about the science behind the Glacial Heat pack? Check out these links:

Teaching Electricity and Simple Circuits to Elementary Students

Circuits in the elementary classroom

Teaching circuits to students

Electricity can be a complex and imposing topic to present to your students. Before we talk about circuits, let’s go over a few definitions:

  • Load - A device that does work or performs a job (i.e., the light bulb in our circuit).
  • Electrical current - The flow of electrons from an area of high concentration (“a lot”) to an area of lower concentration. *Note: the negative side of the battery has a high concentration of electrons.
  • Electron - A negatively charged particle that orbits the nucleus of an atom.
  • Generator - A device that converts mechanical or chemical energy into electricity. Wind, water or an engine can power a generator.
  • Electrical circuit - An electrical path that is closed (all parts connected), allowing the electricity to return to the original source (the battery).
  • Parallel Circuit - A circuit in which the components are connected like a ladder. This circuit splits the voltage equally to all of the components.

Simple Circuit

Creating a Simple Circuit

  1. Place a “D” cell battery in a battery holder. The battery holder will allow you to attach wires with alligator clips to the positive and negative ends of the battery.
  2. Now, screw a small light bulb (mini lamp) into a lamp holder. Like the battery holder, the lamp holder will allow you to attach alligator clips to the light bulb (your load).
  3. To complete the circuit, you will need two wires with alligator clips. Use one wire to connect the negative side of the battery to the lamp holder. It does not matter which side of the lamp holder the wire is attached. Connect the positive side of the battery to the lamp holder using the second wire. This wire will attach to the opposite side of the lamp holder. The light bulb should be lit.

Remember, the voltage of the battery and light bulb should be similar. If the battery voltage is too much larger than the voltage capacity of your bulb, the bulb will burn out. A “D” cell battery provides 1.5V.

Simple Circuit with Switch

Adding a Knife Switch to a Simple Circuit

We will modify our simple circuit described above to complete this task.

  1. Disconnect the alligator clip that is attached to the negative side of the battery and re-connect it to one side of the knife switch. Make sure the knife switch is in the upright position.
  2. Take a separate wire and connect the negative side of the battery to the knife switch. Notice that the light is off.
  3. Lower the arm on the knife switch to connect the circuit and light the bulb.

The knife switch allows you to discuss breaking the circuit and stopping the flow of electrons.

Heath Scientific provides a kit called “Making Circuits Simple” that includes all of the components described in this article. It’s an easy, all-in-one kit to demonstrate circuits to your students.

Volume Density Experiment for Children

Volume Density Experiment

This is an overview of a density experiment provided by Heath Scientific.

The Dynamic Density Kit is a density experiment used to teach children how to measure volume and introduce the concept of density in an easy and fun experiment.

Density is the amount of mass an object has per unit volume at a specific pressure and temperature. In determining density, it is necessary to calculate mass and volume as well. Mass is the amount of matter in a particular object. It is measured in grams. Volume is the amount of space an object occupies.

Volume is measured by determining how much water an object displaces.

To determine density, mass is divided by volume. Since the purpose of the density experiment is to determine the density of different metals, the experiment will require determining the mass and volume of several objects and using simple arithmetic to determine density. This requires the child to measure the volume as well as the mass of certain objects.


The density experiment is completed using the following supplies that can also be found as a package in the Heath Scientific Volume Density Kit.

  • A spring scale
  • A 50 milliliter graduated cylinder
  • 4 different types metal balls with hooks
  • String
  • Paperclip
  • Pipet

The graduated cylinder is used to measure volume for water as well as the different metal balls. Each line on the cylinder is the equivalent of 1 milliliter. If the water level lies between to lines, simply estimate the decimal place.

The spring scale can be hung from a ring stand or simply held in the hand. The scale measures in both newtons and grams. Since the density experiment requires mass to be determined, grams will be the measurement used. As with the graduated cylinder, if the reading falls between two lines, it is acceptable to estimate the value.

Experiment Procedure

The density experiment is conducted by filling the graduated cylinder with water, using the pipet to ensure the correct amount is in the cylinder. Each metal ball is lowered with the string into the water so the child can easily measure volume. The ball is removed from the water and weighed on the spring scale to calculate the mass. This measurement is combined with the value of volume using the formulas given during the overview. The density experiment is repeated for each metal ball to determine the density of each different metal.

This density experiment allows homeschooling parents to easily explain the concepts of mass, density, and volume without a large investment. Additionally, children are shown how to measure volume and use simple arithmetic to calculate the answer to relatively simple scientific questions.

Science project kits such as the density experiment are available from Heath Scientific’s website. These science projects cover a wide range of topics from volume and density to electricity. They offer a relatively inexpensive way for home schooling parents to enhance their child’s education. Additionally, they offer an easy way for parents to improve their home school curriculum as well take an active role in their child’s education by working the experiments alongside their child.

Where you can get Cylinders for volume measurements