W9 l1

Post on 03-Jul-2015

73 views 1 download

description

.

transcript

Conduction. What is it again?

Conduction. It’s the transmission of heat to another object.

Conduction. It’s the transmission of heat to another object.

If a hotter object touches a cooler object, the heat will jump to the cooler object, keeping

it warm and comfortable.

Conduction. It’s the transmission of heat to another object.

If a hotter object touches a cooler object, the heat will jump to the cooler object, keeping

it warm and comfortable.

Metals (and diamonds) are GOOD conductors, Non-metals are not so good…

What is it?

What is it?

Let’s read page 56

What is it?

So, convection is the movement of heat through fluids.

What is it?

So, convection is the movement of heat through fluids.

It is the process that makes hot fluids rise to the top, and cold fluids fall to the bottom.

What is a fluid?

A fluid is a substance that has no fixed shape.

What is a fluid?

A fluid is a substance that has no fixed shape.

What are two types of fluids?

What is a fluid?

A fluid is a substance that has no fixed shape.

What are two types of fluids?

Liquids and Gases

When you heat a teapot full of water, the fire is at the bottom. The water at the bottom gets hot and rises to the top.

Because the rising heat is going away from the hot fire, it cools down.

Cooler water will then fall to the bottom and get hotter.

This will go around and around forever until:

A) _____________?B) _____________?

This will go around and around forever until:

A) You stop the heatB) _____________?

This will go around and around forever until:

A) You stop the heatB) The water evaporates

You can watch the movement of convection with barley seeds.

The water that gets hotter expands – gets bigger.

If it gets bigger, it is less dense.

If it gets bigger, it is less dense.

Close together and small.

If it gets bigger, it is less dense.

Far apart and bigger

If they are more spread out, they weigh less, and rise to the top

Far apart and bigger

If they are more spread out, they weigh less, and rise to the top

Light and floating

Heavy and sinking

Let’s read page 57

So we can see convection in every day life. But you can also see it happen in many

other places:

http://www.youtube.com/watch?v=_OUM7x7iT38#t=7

Here you can see a fluid heating and cooling, rising and falling, in high speed.

http://www.youtube.com/watch?v=aLvk2cbsvzM

Here you can even see convection Moving the skies and the clouds

http://www.youtube.com/watch?v=aLvk2cbsvzM

The warmer clouds are rising upwards, and then spreading out on the top. They

cool down and fall below again.

http://www.youtube.com/watch?v=p0dWF_3PYh4

Here you can even see convection

http://www.youtube.com/watch?v=p0dWF_3PYh4

The lava inside the earth is so hot, it rises upwards. As it spreads across the top, it

pushes the land around, cools down, and falls below again. Just like the clouds!

Draw a three-step process of convection from daily life. Think about these:

1

1 – Heat the fluid

2

2 – Fluid rises up

3

3 – Fluid falls down

3

3 – Fluid falls down

Draw a picture here

Write the sentence here