Lubricants are substances added between two surfaces to reduce the friction between them.

In a fair test, only the variable being tested is changed, so any differences in results can only be due to that variable.

Anomalous results are ones that do not fit the pattern we see for other measurements.

A repeat measurement is when you make a measurement again to check the result.

A mean combines repeat measurements into a single result.

Reducing friction: practical

Science

What forces do

The different kinds of force

Measuring forces

Using force arrows

Balanced and unbalanced forces

Friction

Reducing friction: analysis

Energy

Transferring energy

In the Hidden forces unit, they will build on this knowledge to learn about turning forces, forces that hold objects on a surface, and those that make some objects float.

In primary science, pupils learnt that air resistance, water resistance and friction push back against moving objects. 

This unit focuses on quantifying and comparing energy transfers in different processes, such as motion changes, electrical circuits, and fuel burning. It examines forces as interactions between objects, using diagrams and measurements, including contact and non-contact forces.

Forces

Physical activity and equipment requiring safe use

A lubricant is a substance added to a surface to reduce the ...

A result that doesn't fit with other results.

A result that is very similar to other results.

A scientist slides a mass across a desk three times, in the same way each time. The distances travelled by the mass were 20, 24 and 25 cm. Calculate the mean result. Mean result = {{}} cm.

A scientist slides a mass across a desk four times, in the same way each time, to check for mistakes. The distances travelled by the mass were 22, 19, 23, and 46 cm. Which result is anomalous?

So we can be sure that different results are caused by the one thing we changed.

Which is the correct reason why, in a fair test, the only thing we change is the variable we are testing, and everything we are not testing has to be kept the same?

A scientist slides a mass across a desk four times, in the same way each time. The distances travelled by the mass were 70, 73, 34 and 69 cm. Calculate the mean result. Mean result = {{}} cm.

An object is set sliding across a surface. The greater the friction, the {{}} the distance the object will slide, before it stops.

For a fair test, nothing can be changed between each test.

For a fair test, only one thing can be changed between each test.

For a fair test, only two things can be changed between each test.

For an experiment to be a fair test, how many things can be changed between each test?

They always have another scientist watching the experiment too.

They set up their equipment really carefully.

How do scientists check for mistakes in their results during the experiment?

A scientist slides a mass across a desk four times, in the same way each time. The distances travelled by the mass each time were 34, 37, 55 and 35 cm. Which result is probably a mistake?

Which of the following statements are examples of lubricants (substances added to reduce friction)? 

A scientist slides a mass across a desk four times, in the same way each time. The distances travelled by the mass each time were 54, 57, 54, and 55 cm. What should be used as the final result?

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