Classifying Matter Reflectivity Hardness Magnetic Forces Target 5th Grade Hardness Reflectivity Magnetic Forces

Content Topics Reflection Periodic Table Groups Solubility Conductors & Insulators Magnetism Conducting Experiments Creative Commons Image

Reflection Light interacts differently with different materials. How the light interacts with materials depends on 4 properties.   Surface of the material (rough or smooth) Properties of material (e.g., reflective) Angle the light impacts the material Wavelength (color) of the light

When light is reflected, the light bounces from a “surface”. Sometimes the reflected light bounces in one direction, and sometimes it bounces in a variety of directions. Parallel Diffuse Openstax image Image by MJ Levine

Parallel vs Diffuse Source: www.scienceabc.com

Practice Name some materials that exhibit parallel reflection. Name some materials that exhibit diffuse reflection. What is different about the materials that exhibit parallel vs diffuse reflection?

Materials in the Periodic Table Most of the elements in the periodic table are metals. Shiny Opaque Good Conductors Atoms in a vertical column (group) comprise materials with similar physical and chemical properties, because atoms in a group have the same configuration of electrons.

Valence Electrons All atoms in a particular group have the same configuration of electrons, and this causes the similar properties.

Practice Use your periodic table to find the precious metals, gold and silver. In what group are these materials? Name some of the properties of these materials. Group 2 atoms are called the alkali Earth metals. What are some of the properties of these materials?

Solubility Water & Sugar Solubility is a measure of how much of a material will dissolve. The material being dissolved is called the solute The material doing the dissolving is called the solvent Water & Sugar

Water Water is a polar molecule, and polar molecules can break apart (dissolve) other materials. Polar molecules have slightly charged ends that may attract oppositely charged materials and neutral materials.

Dissolving Different Materials The stronger the chemical bonds of the material are, the harder it is to dissolve that material. High temperatures make it easier to dissolve some materials. Different materials (solutes) require different solvents to dissolve the material.

Life Questions Name some materials that are easy to dissolve. Name some materials that are very difficult to dissolve. Can you name particular solvent and solute pairs that result in dissolving?

Conduction Styrofoam Fiberglass Conduction is the transfer of heat energy from one place to another by direct collisions. Insulators slow or impede the rate of conduction. Styrofoam Fiberglass

Thermal Conductivity The conductivity of a material depends on how free the electrons are to move. Creative Commons Video

Practice Name some materials that are good conductors. Describe the observable properties of these materials. What are some “real world” applications of these materials?

Magnetism Some materials are naturally magnetic due to their electron configurations. Materials that are magnetic are surrounded by a magnetic field. Image: Creative Commons

Magnetic Fields Image: OpenStax

Poles of a Magnet All magnets have 2 poles; this is where the magnetic field is the strongest. North seeking and south seeking poles are determined by alignment of the electron configurations. The ends of a magnet are not charged! Stock Image

Magnetic Interactions Some materials may change their electron configurations temporarily when in the presence of a natural magnet. Ferromagnetic Some materials have electron configurations that cannot be altered by a magnet; these materials are not attracted to magnets.

Practice Which poles of a magnet are attracted to each other? Which repel? If a magnet is cut in half, will each half be a different pole? Explain. Are magnets attracted to all metals?

Video by Minute Physics https://www.youtube.com/watch?v=hFAOXdXZ5TM&feature=youtu.be Video by Minute Physics

Magnetic Domains The intrinsic magnetic moments of electrons align in a magnetic material, creating magnetic regions called domains. Magnetic Material domains not aligned Magnet domains aligned Non-Magnetic Material no domains Image Credit: http://montessorimuddle.org

Practice How will you explain what makes a material magnetic? Can you think of a physical movement activity that would demonstrate magnetism?

Experiments Accuracy is a measure of how close data is to a correct value. Calculating an average may result in a value that is more correct than individual data. Multiple trials allow an average to be calculated which may remove some of the error from data. Precision is a measure of sameness of data values.

Multiple Trials Example: Three people are asked to measure the width of a standard piece of paper. Who obtained the most accurate value? Who measured very precisely? Teresa Alexes Krystina 8.5 10.9 8.6 11.0 10.8 8.4 8.0 10.0 11.1

Comparisons Comparison of values shows by what factor the values are different. Example: Alexes Average = 9.4 = 1.1 Teresa Average 8.5 1

Questions What is the minimum number of trials you plan to have your students record? Why? What are some other data comparisons that could be used?

NGSS Standard 5-PS1-3 Make observations and measurements to identify materials based on their properties. [Clarification Statement: Examples of materials to be identified could include baking soda and other powders, metal, minerals, and liquids. Examples of properties could include color, hardness, reflectivity, electrical conductivity, thermal conductivity, response to magnetic forces, and solubility; density is not intended as an identifiable property.]