UNIT 7: MACHINES

UNIT 7: MACHINES

2.- Simple machines

Simple machines have few parts. They are very easy to use but there are many types of simple machines, they are only variations of the three more important ones: inclined planes, levers and pulleys.

2.1.-INCLINED PLANES

It is a ramp that let us raise and lower objects. It has three main parts:

- Lenght: It is the distance from the beginning to the end of the ramp.

- Height. It is the distance from the tallest part of the ramp to the ground

- Angle: It is the shape the ramp makes against the ground.

2.2.- LEVERS

It is a rigid bar that let us to exert (aplicar) force on a point of support and lift objects. Levers have got three parts:

-        Point of support (fulcrum) : it is where we place the rigid bar acting as a lever.

-        Force: the effort that we exert on the lever.

-        Resistance (load): It is the force made by the object we want to move.

Depending on when these parts are, levers can be first class, second class or third class.

2.3.- PULLEYS

A pulley is a wheel that turns on an axis with a rope that goes around a groove. We use it to raise and lower objects. Pulleys have three main parts

-        Axle. It is the centre part of a pulley. It has a hole that is the axis of the pulley when it turns.

-        Channel. It is the groove the groove the rope is in.

-        Hub. It is the main body of the wheel that joins the axle and groove.

Actvities Unit 7:     Simple Machines

1.- Complete the sentences.

_______________ , _________________ and _____________________________  are the most common simple machines.

2.-  Which parts can you find in a lever?

________________________________________________________ .

3.- Complete these sentences using the following words

            raise                high                bar               move               support

-          A lever is a rigid _________  that moves at a point of _______________.

-          An inclined plane lets you ______________ heavy things up to ___________ places.

-          A pulley lets you  _______________ objects easily.

4.-  Draw an inclined plane  and label its parts.

5.- Draw the three types of  lever and label their parts

6.-  Draw a pulley in your notebook and label the parts

UNIT 6: MATTER

  UNIT 6: MATTER

 

1.3 STATES OF MATTER

Matter has three different states: solid, liquid and gas.

-         Solids. They have a fixed volume and a fixed shape. In some cases we can change the shape of certain solid, for example a block of clay or plasticine.

-         Liquids. They have a fixed volume but they can change shape depending on the container they are in.

-         Gasses. They can change shape and volume. For example we can reduce the volume of gas if we compress it.

     2. MATTER CHANGES

2.1. TYPES OF CHANGES IN MATTER

Matter changes constantly and does not always stay the same. There are two types of changes:

-         Physical changes. This is when the composition of matter does not change. The size, shape, temperature can be different.

-         Chemical changes. This is when matter changes and creates a new substance.

2.2. PHYSICAL CHANGES

 There are two types:

-         Irreversible. This is when matter cannot go back to its original state. It   is permanent. For example:

When you cook an egg, The egg changes.

When you burn a piece of wood, you get ash.

-         Reversible. This is when matter can go back to its original state. It is not permanent. For example:

When you heat chocolate, it melts. When it cools, you get solid chocolate again.

When you mix salt and water, if you evaporate the water,   you can separate the salt and water.

VOCABULARY

To go back: volver

To burn: quemar

Wood: madera

Ash: ceniza

To heat:calentar

To melt: derretir

To cool: enfriar

To mix: mezclar

2.3. CHANGES OF STATE

The main changes of state are fusion, evaporation, condensation and solidification.

-         Fusion/Melting.  This is when a solid becomes a liquid.

-         Evaporation. This is when a liquid becomes a gas.

-         Condensation: This is when a gas becomes a liquid.

-         Solidification: This is when a liquid becomes a solid.

ACTIVITIES

1.-  How many types of changes do you know?

_______________________________________________________________ .

2.-  Complete the sentences.

- Evaporation is the change from ___________  to  ___________  state.

- Fusion is the change  from ___________ to ________________    state.

- Condensation is the change from ___________ to ___________ state.

- Solidification is the change from _____________ to __________ state.

 

3.- Name the changes of state and explain what they are.

FEBRUARY SONG: OPEN UP by LAURIE ANDERSON