PhysSci 3.4

A tool is something that helps you accomplish a task. Scientists use many different tools to observe and conduct experiments. Examples of these tools include:

• Stopwatch: Measures time

• Meterstick: Measures length

• Thermometer: Measures temperature

• Balance: Measures mass

• Spring Scale: Measures force

By making measurements, scientists gather important information, also known as data. For instance, you can use a stopwatch to measure how long something takes or a spring scale to measure how heavy an object is.

The metric system is also known as the International System of Units (SI).

It is a simple system that every country could use to compare measurements.. except the United States

SI is considered to be simple because the units are written in multiples of 10. Which makes it easy to change from one unit to another.

An Olympic-sized swimming pool is measured in meters (m). A meter is the main unit used in the metric system to measure length.

There are other units of length in the metric system that are either
larger or smaller than a meter. They are based on multiples of 10. For example:

-1 millimeter (mm) is one-thousandth of a meter.

This means that if you divide 1 meter into
1,000 equal parts, each part is 1 millimeter.

Mass tells us how much matter is in an object. The basic unit of mass in the metric system is the kilogram (kg). We use kilograms to measure larger objects, like people. For smaller objects, like apples, we use grams (g).

It's important to remember:

• 1 kilogram is equal to 1,000 grams.

This means that when you have a kilogram,
it is the same as having a thousand grams!

Volume is the amount of space that an object takes up. When we talk about liquid volume, we measure it in liters (L).

-One liter is related to meters.

-One cubic meter is equal to 1,000 liters (L).

This means that 1,000 liters of liquid can fit perfectly into a box that measures 1 meter on all sides.

The volume of large solid objects is measured in cubic meters (m ).

The volume of smaller solid objects is measured in cubic centimeters (cm ).

This makes it easier to understand how much space different objects occupy!

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Density is how much stuff (matter) is packed into a certain amount of space (volume).


You can't measure density by itself. Instead, it's a special measurement that you find by using other measurements you already know.

The temperature of a substance is the measurement

of how hot (or cold) it is.


The kelvin (K, without a degree

sign) is the SI unit for temperature. Degrees Fahrenheit (°F) and degrees Celsius (°C) are also used.

Science is exciting and fun, but it can be dangerous.

There are many safety rules that you must follow when-

ever you do an experiment.

• Always listen to your teacher’s instructions.

• Don’t take shortcuts.

• Read lab directions carefully.

• Pay attention to safety information.