What does Density measure? Density: Measure of how compact (close) the molecules of a substance are.

Density Equation Density is a measure of the objects mass in a particular volume. Density = Mass D = M Volume V

Example mass = 200 g D = m Volume = 25 mL V Density = ? D = 200 g D = 8 g/ml

Density Triangle 1. Cover what you are looking for with your finger. M D 1. Cover what you are looking for with your finger. 2. The remaining letters tell you what mathematical function to perform. M D V M = V = DV

If I cut a block of wood in half what happens to the density of the wood?

Stays the Same! Why? Cutting it in half does not change the arrangement of the molecules inside.

IMPORTANT! The density of a substance will stay the same regardless of the size of the sample! We can identify the substance by its density.

Density Table Material Acrylic Aluminum Brass Copper Oak Pine Polypropylene PVC Steel g/cm3 1.1-1.2 2.70 8.4-8.8 8.96 0.6-0.9 0.35-0.50 0.91-0.94 1.39-1.42 7.9

Comparing Density We can estimate the density of an object by comparing it to another object with a known density.

WATER Density of Water = 1 g/ml If an object floats what can you say about its density? If an object sinks what can you say about its density?

Density is < 1 g/ml Density = 1 g/ml Density is > 1 g/ml http://www.onr.navy.mil/focus/blowballast/animation/sub/bouyancy1.swf

Eyepiece (10X) Body tube arm aperture Stage clips stage nosepiece arm Medium power Objective lens aperture high power Objective lens Stage clips Course adjustment stage Fine adjustment Light diaphragm Base

Rules for Microscope 1. Turn on the ___________. 2. Always begin with the _______________. 3. Focus with __________________. 4. Center the object before turning to __________________. 5. Never use the ______________ with the high power objective lens. Low power objective lens light Course adjustment knob High power Course adjustment

100x Center the object scan with low power

400x Then Zoom In

What is “Field of View”? Measurement of the area that can be seen

Is the field of view larger or smaller under high power? Explain.

How do we know how wide the field of view is? We have to measure it while looking through the microscope. 4mm 4mm

2 mm

How many boxes wide is the field of view? 3.5mm

How did you figure out the size of the objects? 4mm 1mm

4mm 1mm How big is the Paramecium? When you place the grid on the stage and look at it under 40x, this is what you see. When you look at a paramecium under 40 x, this is what you see How big is the Paramecium? 1mm

The protist is about 2.5 mm. 5mm

One Volvox = about one third of the FOV 1.6 mm Low Power FOV = 1.6 mm One Volvox = about one third of the FOV = 0.53 mm

Paramecium 0.4 mm High Power FOV = 0.4mm Paramecium= 0.2mm

Amoeba 0.4 mm High Power FOV= 0.4 mm Amoeba = about 0.3 mm

Number that can fit across Size of Object Size of object = Field of View Number that can fit across

9mm

Field of view Number that can fit 3mm 3mm 3mm 9mm 3 = 3mm 9mm

Field of view Number that can fit 3mm 5 0.6 mm 3mm

DO NOW: How wide is the Amoeba? 1 mm

How wide is the euglena? 2 mm 4 0.5 mm

4mm 1mm How big is the Paramecium? When you place the grid on the stage and look at it under 40x, this is what you see. When you look at a paramecium under 40 x, this is what you see How big is the Paramecium? 1mm