Properties of matter Objects: *Describe the two properties of matter *Identify the unites used to measure volume and mass *Compare mass and weight *Explain the relationship between mass and inertia

What is matter? Everything that takes up space and has mass is matter. Matter can be solid, liquid, or gas. All matters have properties that you can observe and compare. Two properties of matter are: Volume and mass.

Volume Feel your desk, your desk takes up space, pour some milk into a glass, the milk takes up space, blow air into a balloon, the air takes place. The amount of space that matter occupies is called volume.

Volume of a liquid Volume of a liquid can be measured by a graduated cylinder. When a liquid is poured into it, the surface of liquid is curved. The curve at the surface of liquid is called meniscus.

We must look at the bottom of the meniscus in order to measure any volume of any liquid. Liquid volume is measured in liters(L) and milliliters(ml).

Volume of a regular shaped solid objects Two unites are used to measure the volume of any solid object; cubic centimeter ( cm 3 ) and cubic meter ( m3 ). There are formulas to find the volume of a regular solid object.

To find the volume of this box, we use the following formula. Volume: Length * Width * Height

Find the volume of this cube

Answer: Volume=Length * Width * Height Volume= 5 cm * 5 cm * 5 cm Volume= 125 cm 3

Volume of an irregular solid object Imagine you want to measure the volume of a rock. it wouldn’t be easy to use a ruler because rocks have so many different shapes. Instead, you use a method called water displacement. Follow these procedures to find the volume of an irregular shaped object using water displacement.

Start with a known amount of water and record the volume. Place the object in the water and record the new volume of the water. Subtract the first volume from the second volume and that will give you the volume of the object.

Example

You might have noticed that the graduated cylinders are measuring in cm3. It actually doesn't make a difference because 1 cm3 is equal to 1 mL The cylinder starts with 200 cm3 of water. When the rock is dropped in, the volume goes to approximately 270 cm3. If you subtract 200 mL from 270 cm3 you get 70 cm3. So the volume of the rock is 70 cm3.

What is mass? Another property of matter that can be measured is mass. Mass is the amount of matter that is in an object. all matter including you has mass.

Mass does not change when location changes. Your mass is the same on earth, on moon or on mass. We use a balance to measure mass Mass is expressed in kilograms (Kg), grams (g) and milligrams (mg).

What is weight Weight refers to the gravitational force experienced by an object due to gravity The more mass an object has, the greater the gravitational force on the object and the greater the object’s weight. An object’s weight differs according to the gravity Example: an object would weigh less on the moon than it does on Earth because the moon has less gravitational force that Earth does.

Open your books page 41 and observe Figure 5, the difference between mass and weight.

Calculating wight Weight is measured in Newton (N) 1 Newton is equal to the weight of an object that has a mass of 100g on Earth 1N=100g

A student has a mass of 45,000 g. How much does this student weigh in newtons? Step 1: Write the information given to you. 45,000g Step 2: Write the conversion factor to change grams into newtons. 1 N= 100g Step 3: Write the equations so that grams will cancel. 45,000g * (1N/100g) = 450N

What is inertia? Objects tend to keep doing what they’re doing. If they are moving they will keep moving with the same speed unless something acts on the object to stop it or change its speed or direction. This tendency of an object to resist a change in motion is called inertia. Mass is a measure of inertia. The more mass an object has, the more inertia it has.

For example, imagine you are going to push a grocery cart that has only one potato in it. Pushing this cart is easy because the mass and inertia are small. But suppose the grocery cart is full with potatoes, now the total mass and the inertia of the cart is much greater. Thus it will be harder to get the cart moving and once the cat is moving, stopping the cart will be harder.

Home work: page 43, questions 3,4,5,6,7,8,9 and 11.