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What is a model?
Represents a system for the purposes of analyzing and understanding that system
Can test to see if it meets expectations i.e. stream table
Explanatory ideas that are expressed in words and mathematics that are used instead of physical models because of time, distance and scale.
- Earth-centered model
- Ptolemy's model of the universe was geocentric. Planets orbited the Earth.
- Sun-Centered Model
- Copernicus' model of the universe was heliocentric. Planets orbit the sun.
What is a black box?
Any system that can't be observed or touched directly and can't be completely understood. i.e. the Earth's core
It Takes All Sorts Activity and Creature Features Worksheet
Sorting once, then once again until each is in their own group. Teaches sorting and organizing.
What is the purpose of teaching students to classify and sort objects?
Teaches students how to organize. Organization is used in decision making and contributes to the ease of remembering things.
What is a dichotomous group?
A group that is divided into two sharply distinguished parts or classifications.
Taxonomic Hierarchy System
Why is it important to understand vertical alignment of the TEKS in content areas?
Each year builds on the previous year
Metric System Conversions
- Kilo - 103 - King
- Deka - 101 - Died
- Deci - 10-1 - Drinking
- Centi - 10-2 - Chocolate
- Milli - 10-3 - Milk
What are the 4 metric units we use every day and what does each one measure?
- Meter - to measure length
- Kilogram - to measure mass and/or weight
- Degree Celsius (Kelvin) - to measure temperature
- Second - to measure time
What are the 3 metric units used in scientific applications?
- Ampere - to measure electric current
- Candela - to measure luminous intensity
- Mole - to measure amount of substance
What metric unit is used to measure volume?
Liter - measures liquid
the amount of space an object takes up
What is the formula for finding the volume of a cube?
What is the formula for finding a solid rectangle?
Length x Width x Heigth
What unit is used to report volume?
Cubic cm = cm3 = cc = mL
How can you find the volume of an irregularly shaped solid?
- Use the displacement method and an overflow can
- Water Displacement Method - measure > put object in (just under water if floating) > measure > take difference
Bottom of curved surface
the property of a body that causes it to have weight in a gravitational field
Gravitational force exerted on an object by Earth
a metric unit of weight equal to 1/1000 of a kilogram
- the study of how size effects the relationship between weight, strength and surface
- think ants carrying 10x's their body weight
anything that has mass and volume, made up of atoms and molecules
What are the physical properties of matter?
- Chemical - you can see when the substance undergoes a chemical change, think rust
- Physical - can observe or measure, no change in composition
measure of how much matter is squeezed into a given space
What is the formula for finding density?
Density = mass/volume = gram/cm3
Smokestack Jar Activity Results and Conclusions
Hot water is less dense and rises or floats on the more dense cool water. This movement of heat energy is by a natural convection.
Floaters and Sinkers Activity - Results and Conclusions
- Why sink or float?
- Gravity - the mutual attraction between bodies that is proportional to the masses of the bodies and the distance between them
- Density - comparing 2 densities, take into account mass and volume
- Buoyancy - an upward force (push or pull) acting on all objects in fluids whether they are floating or submerged. Upward force is call buoyant force, which works against the downward force of gravity. As long as buoyant force is greater than downward pull of gravity the object will float.
Why do diet drinks float?
The reason the diet drinks float and the regular drinks sink is directly related to the density of the liquid in each can. The difference between a can that floats and a can that sinks is the amount of sugar in the drink. Sugar is much more dense than water, and corn syrup is also heavier than water.
Density Activity - Results and Conclusions
Measuring the density of a small piece of glass, metal, plastic and wood by the water displacement method, it was found that the higher the mass the higher the density. If the material has a density of less than 1 (pure water) it will float.
The Floating Egg Activity - Results and Conclusions
Testing the differences in the density of fresh water and salt water. The egg will sink in the fresh water and will float in the salt water. The egg's density is greater than the fresh water causing it to sink but the salt water's density is greater than the egg causing the egg to float.
The Dancing Raisin Activity - Results and Conclusions
The raisins will float to the top because CO2 bubbles from the Alca-Seltzer attach to the raising and raise it up. When the raisins reach the top, the bubbles break and they sink. Raisins and CO2 work as a system - the combination is less dense than water.
The Cartesian Diver Activity - Results and Conclusions
Demonstrate Archimedes principle and show that pressure works in all directions. The eye dropper fills up with water and sinks to the bottom when the bottle is squeezed. When the pressure is let go, the eye dropper releases the extra water and floats back to the top. The pressure on the bottle forces water up the eye dropper. Since the eye dropper becomes heavier it drops. Squeezing anywhere on the bottle produces the same results so it can be concluded that pressure works in all directions.
Liquid Density Activity
Every liquid has its own density, the liquid with the greatest density will layer at the bottom of the cup, and with every liquid poured in, a layer will form with its layer placement based on the liquid's density.
What is the density of pure water?
Density of Pure Water = 1.00
Why does ice float?
- Density of Pure Water = 1.00
- Density of Ice = 0.92
- Ice density is less than water density, therefore it floats
an upward force (push or pull) acting on all objects in fluids whether they are floating or submerged
Define Buoyant Force
Upward force of an object in liquid
What is Archimedes Principle?
The buoyant force exerted on an object in a fluid (gas or liquid) is equal to the weight of the fluid displaced by the object NOT the weight of the object itself.
Clay Boat Activity
- Why does the boat float when flat, but the ball of clay does not? The boat is a clay-air system.
- Density of the boat is less than the density of the water because of the air. Clay ball is greater than the buoyant force of the water.
Floating Soap Bubble Activity
- Alka-Seltzer Test (gas and buoyancy)
- Alka-Seltzer dissolved in water > bubbles will float on the CO2 gas that the Alka-Seltzer produces