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Fierce Fifth Graders
Material World
1. Atoms and Molecules
2. Periodic Table of the Elements
3. Changes in Matter
4. Properties of Matter
1. Understand, Matter Atoms and Molecules
All matter is made up of atoms.
An atom is the smallest unit of matter and consists of a dense, central, positively charged nucleus surrounded by a complex system of electron orbitals. Atoms are not divisible by ordinary chemical or physical means.
Atoms have three basic components:
Proton: has a positive (+) charge
Neutron has no charge
Electron has a negative (-) charge
Protons and neutrons make up the nucleaus (center) of an atom. Electrons are found in complex orbitals that form the electon shells. The electrons are constantly in motion around the nucleus. An atom has the same number of proton and electron.
An element is a substance consisting of atoms which all have the same number of protons. Elements are represented by chemical symbol. All the elements found so far are presented on the Periodic Table of The Elements.
An atom of hydrogen has one proton in its nucleus, whereas helium has two protons in its nucleus. The number of protons in a particular atom determines the atom’s identity and, therefore, is always the same.
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2. Periodic Table of the Elements
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3. Changes in Matter
Click here to acess a great website with a video and a quiz to test your knowledge!
Physical Changes
Occur when objects or substances undergo a change that does not change their chemical composition
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Easily reversed
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No new product
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Often just a state change
(liquid to gas, solid to liquid, …)
Ex: ice melting
Chemical Changes
Occur when a substance combines with another to form a new substance.
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Not easily reversed
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New product(s) is(are) formed
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often, heat light, sound fizzing occurs
Ex: wood burning
4. Properties of Matter
Click here to acess a great website with a video and a quiz to test your knowledge!
All elements have properties that we can use to identify them. For example we can identify a person by their face, their voice, height, finger prints, DNA etc. The more of these properties we can identify, the better we know the person. In a similar way matter has properties - and there are many of them.
There are two kinds of properties: physical and chemical.
Physical properties of matter are usually those that can be observed using our senses. Examples of physical properties are:
Mass
Mass is the amount of matter that makes up an object. It is measured with a balance unit is grams (g).
Memory trick: mass and matter begin with the same 2 letters.
Volume
Volume is the amount of space an object takes up. It is measured with a ruler for cubes and rectangular prisms (length x width x height) or using water displacement for odd-shaped objects. The units used are centimeters cubed (cm3) or milliliters (mL)
Magnetism
Magnetism is property of attracting certain metals, just like a magnet.
Density
Density depends on the mass of a substance per unit volume. It determines whether an object sinks or floats. Styrofoam is less dense than water– so it floats. A rock is denser than water – so it sinks.
Solubility
Solubility means that matter can dissolve in a liquid.
Salt is soluble. When it is put in the water it seems to disappear, but it’s still there.
Insolubility
Insolubility means that matter CAN’T dissolve in a liquid. Oil is not soluble, so we call it insoluble.
Conductivity
Conductivity is the ability to conduct heat or electricity. Metals are the best conductors.
Insulation
Insulation means that matter that DOES NOT allow heat or electricity to travel through it. Styrofoam is a great insulator.
Color
Color is the light that is reflected or absorbed by matter.
The leaf takes in red, but reflects blue and yellow (which makes green). That’s why we see it as green.
Texture
Texture the roughness or softness of a surface. Sandpaper is made to have a rough texture.
Flexibility
Flexibility means that solid matter bends without breaking when force is applied.
5. Buoyancy
Buoyancy – Ability to float or rise to the top of a liquid.
One of the factors that explain why objects float or sink is density.
Density – How closely packed together the molecules of a substance are.
There are two things that have an impact on density:
· The mass the material (in kg).
· The volume or amount of space the material takes up.
Density is a measurement of how solid something is. Specifically it is the mass (how much matter of ‘stuff’) per unit volume of a substance. If you have two objects of the exact same size (volume), the more dense object will weigh more than the less dense object.
Ex : Imagine you have a golf ball and a ping pong ball of the same size. Which object will float and witch one will sink?
An object will float if the density of the object is smaller than the density of the water displaced. An object will float if the density of the object is higher that the density of the water displaced.
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