- What is Mass?
- The mass of an object is NOT dependent upon the value of the acceleration of gravity.
- The standard metric unit of mass is the kilogram.
- Mass depends on how much stuff (matter) is present in an object.
- The mass of an object is NOT variable and DOES NOT dependent upon its location.
- An object would have the same mass on Mount Everest as it would have in the middle of Lake Michigan.
- People in on diets are really concerned about their mass. They really want to loose mass and not weight.
- The mass of an object IS NOT measured in pounds. Pounds is a measure of force. Mass is measured in grams or kilograms.
- It takes more force to accelerate an object with a greater mass than an object with lesser mass.
- If all other variables are equal, then it would require less exerted force to stop a less massive object than to stop a more massive object.
- The mass of an object is mathematically related to the weight of the object.
- What does viscosity mean?
Viscosity is a measure of how resistant a fluid is to substances moving through them.
The simplest answer is that viscosity is a measure of how thick a fluid is. The greater the viscosity the thicker is the fluid.
Water is considered a thin or low viscosity liquid in comparison to honey, which is a thick or high viscosity fluid.
Viscosity is also a measure of how easily a fluid flows. Water, being a low viscosity liquid flows faster than honey, which is a high viscosity liquid.
To understand viscosity, you need to understand fluids, which are liquids and gases.
Properties of Newtonian (common) fluids (gases or liquids)
1. Have no fixed shape, instead they take the shape of their container.
2. Easily yield to external pressure. This means that fluids move out of the way, allowing something to move through them.
3. Free-flowing substances. This means the molecules making up a fluid can move past each other.
- What is the difference between dyes and pigments?
Dyes and pigments are considered colorants, meaning they are substances that impart coloring to a material.
Dyes are soluble coloring material. Dyes are absorbed into the material to which they are applied. Dyes are transparent. While dyes bring about color changes in wood the molecular size of the dye particles is so small that light is able to pass through.
Pigments are insoluble coloring material.
Paint is a mixture of fine particles of coloring material in a solvent. When applied to a material, the pigments form a thin layer on the surface of the material and actually bond with the surface.
Stains are basically very dilute paints made up of pigment, a carrier and a binder.
- How can I prove that gas is a phase of matter?
Matter is anything that takes up space and has mass. Gases are one state of matter.
Physical Properties of Gases
Gases are neither close together nor fixed in place. This means that the shape and volume of a gas depends on the shape and volume of its container.
Air is the mixture of gases in earth’s atmosphere. By volume, air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. Air also contains water vapor. The average amount of water vapor at sea level is about 1%. Considering the entire atmosphere surrounding earth, there is about 0.4% water vapor.
Water Vapor is water in its gas state at a temperature below its boiling point.
Humidity is the amount of water vapor in the air for a specific region.
Activity: Gas takes up space.
Purpose: To demonstrate that air takes up space, thus it is an example of matter.
Use an empty plastic see-through bag. With the end open, swish the bag through the air, then squeeze the opening closed. The bag is filled with air. Air in the room is not visible nor is the air in the bag visible. The air molecules in the bag are pressing against the inside of the bag, thus there is a shape. You might change the shape some if you press against the bag, but basically the volume and shape of the gas inside the bag remains constant.
Gases are a state of matter because they have mass and take up space.
Stuff a balloon inside an “empty” plastic bottle. Strectch the mouth of the balloon over the mouth of the bottle.
Make a Prediction: Can the balloon be inflated inside the bottle? Explain your answer.
Investigate: Hold the bottle and blow into the mouth of the balloon. Note: The balloon’s mouth must remain over the top of the bottle so that the boottle’s mouth is sealed.
What happened? Can you explain the results with the knowledge you have about gases?
- Can crystals be grown without heat?
Crystals grown by the evaporation method are generally larger and better formed. This method is slower but the results are worth the wait. Basically a solution is made with water and a crystalline solid, such as copper sulfate or potassium aluminum sulfate (alum). Copper sulfate and alum crystals grow best with the evaporation method.
1. Use a very clean container and work in as dust free environment as possible.
2. Make a saturated solution using distilled water as the solvent.
A saturated solution is made by adding a solute until no more will dissolve.
Use the Wikapedia Solubility Table to decide the mass of solute that will dissolve in 100 mL of water atambient (room) temperature. http://en.wikipedia.org/wiki/Solubility_table
- How to make a saturated copper sulfate solution.
At room temperature, about 32 g of copper sulfate will dissolve in 100 ml of water. Dissolve copper sulfate in distilled water until this solute stops dissolving. At this point there will be crystals of copper sulfate that settle to the bottom of the container and no amount of stirring will cause these crystals to dissolve.
Caution: Adult supervision is required when handling copper sulfate because it is toxic. Copper sulfate is used to kill roots in drains. Do use special precautions when working with this toxic chemical. Toxic means poisonous; Wear gloves, an apron, and goggles. Alum is not toxic. But you do not want to get it in your eyes. So wear goggles and an apron is always suggested.
- Pour the saturated solution through filter paper to remove any undissolved solute. The diagram shows a funnel lined with filter paper. You can use a coffee filter or even a paper towel instead of filter paper. Keep the filtrate (liquid that passes through the filter). This is the saturated solution.The solid copper sulfate left in the filter can be dried and saved for future use.
- How to make a saturated of alum (hydrated potassium aluminium sulfate with the formula KAl(SO 4)₂·12H 2O.)
At room temperature dissolve about 10 grams of alum in 100 ml of water.
3. Cover the container with piece of paper and insert a craft stem through the center of the paper and down into the solution.
You want the solvent (water) to evaporate slowly at ambient temperature (room temperature). As the water evaporates the solution becomes more concentrated, meaning the ratio of solute to solvent increases. You now have a supersaturated solution. This means that there is more solute dissolved in the water than normal at ambient temperature (room temperature).
Supersaturated solution are unstable, which means the excess solute dissolved in the water tends to precipitate (fall out of solution). Some crystals that participate attach to the craft stem. These are called seed crystals, which provides a surface for other precipitating crystals to attach to. The size of the crystals continues to grow as more solute falls out of solution and sticks to the crystals.
- How to make a saturated copper sulfate solution.