Science

Force - define force / what is a force?

Contact (direct - physical contact required) / non-contact (indirect - no physical contact required / can act at a distance) forces

Examples of forces (e.g. gravity, normal force, applied force, electrostatic force, magnetic force, air resistance)

Balanced and unbalanced forces

Net forces and how to calculate

Measuring forces (using spring balances, measuring in Newtons)

Free body diagrams - including predicting direction of movement

Forces experiment - using spring balances, using simple machines, calculating averages, constructing column graphs

How to Construct a Perfect Column Graph

To make sure your graph gets top marks in science, you need to follow the steps below.

1. Title

Always give your graph a clear, descriptive title at the top.

Example: "Graph showing the favorite sports of Year 7 students."

2. Axes (with a Ruler!)

X-axis (Horizontal): Goes across the bottom. This is where you put your categories (Independent Variable).

Y-axis (Vertical): Goes up the side. This is where you put your numbers (Dependent Variable).

3. Labels & Units

Clearly label both the X and Y axes so the reader knows what they are looking at.

If you are measuring something like height or time, always include the units in brackets, like Height (cm) or Time (seconds).

4. Scale

Your numbers on the Y-axis must go up by the same amount every time (e.g., counting by 2s, 5s, or 10s).

Start your scale at 0 at the bottom corner.

Space your numbers out evenly along the grid lines.

5. Gaps

Draw your columns with equal widths.

Leave equal gaps between your columns. In science, the columns should not touch each other!

Top Tips:

Always draw your graphs in pencil first so you can erase mistakes.

Always use a ruler for your axes and your columns.

Net force

Balanced and unbalanced forces

Spring balances

Newtons (as a unit of measurement)

Direct (contact) and indirect (non-contact) forces

Accuracy:

What it means: How close a measurement is to the true or actual value.

In the lab: Accuracy depends on using high-quality equipment properly.

Example: If a liquid is exactly 20°C, and you use a digital thermometer to measure it at 20.0°C, your data is accurate. If you use a cheap plastic thermometer and read it as 24°C, it is inaccurate.

Reliability:

What it means: How consistent and repeatable the experimental results are.

In the lab: Reliability is about checking if your results were a fluke. You achieve it by repeating the experiment multiple times (doing trials) and checking if the data is similar.

Example: If you roll a marble down a ramp three times and it takes 1.5 seconds, 1.6 seconds, and 1.5 seconds, your results are reliable because they are consistent.

Validity:

What it means: Whether the experiment is a fair test that properly investigates the aim.

In the lab: An experiment is valid if you have successfully controlled all variables except for the one thing you are intentionally changing.

Example: If you want to find out which fertilizer makes plants grow tallest, every plant must get the exact same amount of water, soil, and sunlight. If one plant gets more sunlight than the others, your experiment is invalid because it is no longer a fair test.