Matter Notes

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Matter Notes : 

Matter Notes These will be available online.

Atoms are too small to be seen so how do we know about them? : 

Atoms are too small to be seen so how do we know about them? Observations are made during experiments and then we infer things about atoms based on our observations.

Atoms combine to make molecules : 

Atoms combine to make molecules Molecules are made up of two or more atoms.

How and why has our model changed? : 

How and why has our model changed? How? It has changed from being the same throughout to being made of smaller charged particles to having a nucleus. Why? We’ve done more experiments with better technology and learned new things.

Current model of the atom : 

Current model of the atom Protons (+) Neutrons (neutral) Electrons (-)

What are the limitations of our model of the atom? : 

What are the limitations of our model of the atom? The electrons are really far away from the nucleus. If the nucleus were the size of an orange, the electrons would be as far away as the size of the school. The movement of the electrons is not in specific paths.

Density : 

Density How do we find the mass of an object? Scale – (Triple beam balance) How do we find the volume of an object? If it is a rectangular solid Length ∙ width ∙ height If it is irregularly shaped use displacement Use a graduated cylinder and see how high the water moves up when the object is put in.

You can tell by observation which object is more dense : 

You can tell by observation which object is more dense The less dense substance will float and the more dense substance will sink. Examples: Warm air rises because it is less dense. Warm water rises because it is less dense. Ocean in a bottle – denatured alcohol sinks and paint thinner floats. Eggs float in salt water but not fresh water because salt water is more dense.

Examples : 

Examples Warm water rises

What evidence do we have that particles of matter are in motion? : 

What evidence do we have that particles of matter are in motion? Air freshener spreads out to every part of a room. Vanilla escapes from a balloon. Food coloring spreads out in water.

Temperature affects how fast particles of matter are moving : 

Temperature affects how fast particles of matter are moving When particles are heated up they will speed up and spread apart and become less dense. When particles are cooled down they will slow down and get closer and become more dense.

Examples : 

Examples http://www.miamisci.org/af/sln/phases/index.html

Substances expand when they heat up and contract when they cool down. : 

Substances expand when they heat up and contract when they cool down. Cracks in the sidewalk are made so that they can expand in the hot summer sun and not crack. The liquid in a thermometer expands and moves up when it heats up.

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