Sink Float Suspend Challenge Challenge: Make the film canister float, make the film canister sink, Then make the canister stay suspended in the middle Safety: Keep water at the sinks Clean up any spills Act in a responsible manner

Sink Float Suspend Challenge Did the mass change? Did the volume change? How does a sub work? What other objects sink? What other objects float? What determines if something can sink or float? Sub: https://www.youtube.com/watch?v=yb3e4IegeJ0

If volume> mass it will float If mass>volume it will sink If mass=volume it will be suspended

Ask a question: What is happening? Why?

Why do these float?

Floating and Sinking Orange Demo What will an orange do in water?

Explain this??? Why does an orange with a peel float, but without its peel, it sinks? How did its mass change? How did its volume change? What determines if something can sink or float? Its mass? Its volume? Both?

Density

What is density? Density is a ratio of how much matter there is in a certain amount of space. A measure of how many particles are packed into a certain area.

More dense = more particles in a space Less dense = less particles in a space

How do I find density? I need to find out how much stuff (mass) is in a certain amount of space (volume)

What instruments do I need? To find the volume of the object Ruler or graduated cylinder Units are cm3 or mL To find the mass of an object Triple Beam Balance Units are g

How do I calculate density? Density = mass OR mass ÷ volume. volume Units for density: g/cm3 or g/mL ALWAYS REMEMBER UNITS!

Does the sample size affect the density of an object? Do all these pieces of gold have the same density?

Does the sample size affect the density of an object? In other words, if I break off a piece of this cube, will it have a different density than the whole piece? NO!!!

Density is based on total mass divided by total volume. When one changes, the other also changes, so the density (which is a ratio) stays the same!!! https://www.youtube.com/watch?v=ijj58xD5fDI

Which one is more dense? Which table group is most dense in the classroom? How about this: Which square is more dense?

Density of Water Water has a density of 1g/mL If an object has a density greater than 1g/mL, it will sink in water If an object has a density of less than 1g/mL, it will float in water.

What do we know about the density of diet coke vs. coke vs. water?

Do liquids have different densities? Yes! So what happens when you mix them? They form layers with the most dense liquid falling to the bottom. Alcohol = .80 g/ml Vegetable Oil = .90 g/ml Water = 1.0 g/ml Salt Water = 1.2 g/ml

The density of the liquid affects how you float too! Denser liquids help you float more easily. That is why it is easier to float in the ocean, than in a freshwater lake.

Illustrating Density

Metals have different densities Lead 11.3 g/cm3 Aluminum 2.7 g/cm3 These are all over 1.0 g/ml and most ships are made of metal. So how do boats float?

Explain why one bowling ball floats and one sinks http://www.youtube.com/watch?v=NqNGW0oOXE4

Density affects many of Earth’s processes

Density helps create ocean currents

Density helps move melted rocks under Earth’s crust mantle core Hot material rises, cooler material sinks, creating a current, called a Convection Current

Solid Land has different densities Continental Plates – lighter, thicker, (less dense) made of granite Oceanic Plates – heavier, thinner, (more dense) made of basalt

Convergent Boundary Plates move toward each other The more dense oceanic plate subducts under the less dense continental plate

Normal and Low bone densities Low density bones break more easily.

Temperature can affect density Remember. . . Warm air rises. So this means warm air is less dense than cold air and it rises

Density causes your attic to be hot in the summer

Try it! Follow the directions for the ice experiment and see if you can explain what is happening Safety: Wear your goggles! Clean up spills. Follow all directions. No eating or drinking during lab.

Step 1 50 mL isopropyl alcohol 50 mL water 4 ice cubes

Step 1. Observations Make observations about: Ask Questions State of matter Color Odor Temperature Clear/opaque Other Ask Questions

Step 2 50 mL isopropyl alcohol 50 mL water 4 ice cubes

Step 3- after 5 minutes 50 mL isopropyl alcohol 50 mL water 4 ice cubes

Explain what happened? Density of known substances Water 1g/ml Ice 0.9167 g/ml alcohol 0.786g/ml What do the ice cubes do in water? Why? What do the ice cubes do in alcohol? Why? What do the ice cubes do in alcohol after 5 mins? Explain why using data to support your conclusion.

Where would an ice cube go if I dropped it in this container?

Materials denser than water sink Materials less dense than water float

Identifying matter using Density What material is this block made of? How can I figure it out? Find its mass (135g), find its volume (15mL), calculate its density. 135g/15mL = ? Then compare your answer with the known substances to identify it.