Chapters 1-3


Scientific Method

1. Identify Problem

2. Gather Data

3. Form Hypothesis

4. Perform Experiment

5. Analyze Data

6. Conclusion

Reaction in a Bag

This is the lab where substance A and B are put on two corners of a plastic bag, then mixed together after student places a red liquid in the bag.

Students found that substance A provides heat and some color, but substance be turns cold and gives a light pink color.


Observation- Information obtained by the sense, often by direct measurement.

Inference- A conclusion based upon known observations.

Hypothesis- A purposed solution to a scientific problem.

Control Group- The group in the lab that is left alone for comparison to the experimental group.

Experimental Group- The group in the lab that is tested on and receives the variable being tested.

Control Factors- Variables that are held constant. They are the same for both the control group and the experimental group. (ex: how much you stir a liquid in a tube)

Indicator- A substance used to show the presence of another substance

Volume- the amount of substance that something takes up.

Volume Displacement Technique- quick and easy way to determine the volume of a solid or gas. Used many for things that have holes in them (Ex: rock).

Mass- the amount of matter in a substance. ( true of solids, liquids, and gasses)

Meniscus- the curved bottom of the graduated cylinder. Used to measure the liquid in the graduated cylinder. Must read at eye-level.

Baking Soda

This is the lab where students heated up a graduated cylinder with baking soda in it, and compared it to a control group of a cylinder with the same substances in it, but is not heated. Afterwards, students poured tea in both cylinders to spot the difference.


The glass at the bottom of the tube was burning, not the actual baking soda. Also, there is condensation at the top of the tube, because the outside air is much cooler than the inside of the test tube. The control group was the unheated baking soda, experimental group was the heated baking soda, and the indicator was the tea.

Control Factors:

-amount of baking soda

-amount of tea

-same type of tea

-amount of stirring time.

The condensation on the top of the cylinder is less than the amount of baking soda, because the condensation comes from the baking soda, therefore it cannot become greater than the baking soda. Carbon Dioxide is the gas that comes out of the baking soda.

Experimental Errors:

1. A hole in rubber tubing

2. Stomper isn't on tight enough.

3. Tubing is not on the top of the bottle.

4. The burner is capped too early.

Baking Soda makes things rise when heated. Therefore that is why it's used during cooking. It is Sodium Bicarbonate.

1.2 Volume Notes

To find the volume of a solid that cannot get wet, do length x width x height, or a x b x c. There are 100 centimeters in one meter.

If a graduated cylinder is more taller and less wider, it has more spaced out increments because there is less surface.

Single Pan Balance Notes

1. Always check that the pan is clean and dry.

2. Always zero the balance before each massing.

3. Never switch pans between balances.

4. Pick up balance by red bar only.

5. Return riders to zero when done.

1.4 Lab The Use of the Water Displacement Technique

This is the lab where the students first used the water displacement technique using sand. Students poured a certain amount of water in the graduated cylinder, then poured the sand into the cylinder. The change of volume is the volume of the sand without the air. Students found the volume first with the sand and air. To find the fraction of sand that is air, divide air by the dry sand.


Volume of Dry Sand: 56

Volume of Water: 42

Volume of Sand and Water: 94

Volume of sand alone: 52

Volume of Air: 4

% of dry sand that is sand: is/of = sand alone divided by dry sand= 93%

% of dry sand that is air: is/of= air divided by dry sand= 7%

Volume of water that fills the air space: (basically what is the air space) 4

Volume of water doesn't fill air space: (water minus air) 38

Experimental Errors:

- Sand sticks to the side of the wet cylinder

- Record sand level not H2O level

- Pour H20 into sand (volume of sand plus water increases)

- Sand gets stuck in the funnel

- Pour sand too fast, it overflows

1.8 Sensitivity of A Balance Lab

This is the lab where students find the sensitivity of each balance. Also, students found that if you mass the same object, will you get the same mass? The mass will not be the same, but extremely close. Divide the number of changes of mass by the change of mass, and you will get the sensitivity of the balance.

The sensitivity of balance is the margin of error your balance has when massing an object.



Histogram- a bar graph that shows the number of times a value is represented for a large sampling group.

Conservation of Mass- In all changes, mass is exactly conserved, provided nothing is added or allowed to escape. Must be a closed system! Not true for volume though.

Laws of Nature- Guesses generalization based on many experiments. Can be adjusted when necessary to account for any changes in the limitations of a law.

2.1 Lab: Mass of Dissolved Salt

This is the lab where the students discovered that if salt dissolves in water, will it lose its mass? The answer is yes, but a small change.

Experimental Errors:

- Cleaning pan btwn Mi and Mf

- Salt spills from cap to bottle

- Remove cap before the Mf

- Not shaking long enough

- Cap isn't on tight enough ( the H2O spills out)

- Not drying the cap (salt starts to dissolve)

- Bottle wet on outside of Mi

( Most of these lead to decrease in mass )

Remember that if you leave water with dissolved salt in it in the sun, the water will evaporate and the salt will still be there.

2.4 Lab Ice Ice Baby ;)

This is the lab where students put an ice cube in a cup to see if the mass will be lost when it melts. Students discovered that mass is lost, but only a little. Although, there really should be no change because of the law of conservation of mass. There is condensation on the outside of the bottle, because it is a lot cooler in the inside of the bottle than the room temperature.

Experimental Errors:

- Shaking the bottle

- Leaving the condensation droplets on the bottle

- Not letting the ice melt all the way

- Not drying off the bottle

- Opened the cap off the bottle

2.5 Lab: The Mass of Copper and Sulfur

This is the lab where students tested if copper and sulfur would lose mass when heated together. Students discovered that the mass barley changed.

Experimental Errors:

- shaking test tube

- hole in rubber sheet

- sheet is not on tightly

- capping the burner too early

2.6 Lab: The Mass of a Gas

This is the lab where students tested to see if when a solid and liquid produce a gas, will the mass change. They discovered that there should be no change because of the law of conservation of mass.

Experimental Errors:

- cap wasn't on tight enough

- not drying the outside of the bottle

- not drying the cap

- Removing cap

- water splashes out when loosening cap

2.7 Law of Conservation of Mass

In a closed system mass will remain constant, regardless of the actions of the processes inside the closed system. Mass is always conserved, however, in a nuclear reaction some mass is lost. The energy released in a nuclear reaction will be absorbed into surrounding material, adding mass to it. So the mass is not really "lost".



Density- Mass per unit volume of any substance. Unit of measure is g/cm3


Property of a object: describes the object itself

Property of substance: identify what the object is made of

3.2 Mass and Volume

This is the lab where students tested if the mass of a object will depend on its shape or the substance it's made of. Students discovered that the shape depends on its volume, but the same substance will have around the same density

Experimental Errors:

- re-mass same cylinder

- cylinder is still wet

- not enough water in cylinder

- H2O splashes out of graduated cylinder

Mass & Volume Notes

- Objects that are made of the same substance that have the same volume will have the same mass

- The mass of an object will double if the volume doubles

- Objects that have the same volume but are made of different substances will not have the same mass.

3.3 Density

Remember: g/cm3

M/V= D

3.5 Lab : The Density of Solids

This is the lab where students compared 3 metal objects to see if they are made of the same substance. They also used the water displacement technique to find the volume of a rock. The students discovered that the only 2 of the metal objects are of the same substance, while the second cube is most likely made of a different substance, even though it looks and feels the same as the other cubes. The rock is a sedimentary rock which means there are different substances being compressed inside the rock.

Experimental Errors:

- Massing the rock after finding the volume

- Mixes up cubes

- Measuring a side of a cube/slab twice

- Measure from end of ruler not 0

3.6 The Density of Liquids

This is the lab where students used density to compare 2 liquids to see if they are made of the same substance. They discovered that the two liquids are made of the same substance. Substance A and B were Magnesium Sulfate, or Epsom Salt.

Experimental Errors:

- Student did not dry cylinder before massing

- Liquids sticks to inside wall of cylinder

- Dry out cylinder after its massed

3.7 Density of a Gas

This is the lab where the students produced and collected a gas to find the density of the gas. This lab used the 10 x cm-3 technique.

Experimental Errors:

- Hand not tightly on the cap of bottle when pulling it out of the water

- Spill water when finding the volume in the bottle

- Break tablet after Mi

- Hole in tubing or stopper falls off

- Air bubble in bottle

- Did not put foil on the pan

Density of the Air in Classroom

The density of air is 1.2 x 10^-3

The formula is:

d/g/cm3 times m/volume

Dimensions: 12m x 9m x 4m

V= 1200 x 900 x 400 ( they are meters, and they need to be centimeters. It doesn't fit on a calculator, so you need to do this): The answer is 432000000, so it would need to be 4.3 x 10 ^8

You then could do 1.2 x 10^-3 times 4.3 x 10^8.

Answer: 5.2 x 10^3

Practice Questions

1. Why is Baking Soda Used in Cooking?

- It makes things rise

2. How many kilograms are in a gram?

- 1,000

3. How many centimeters are in a meter?

- 100